paper under high pressure: spherical glass flotation and

P A P E R

Under High Pressure: Spherical GlassFlotation and Instrument Housingsin Deep Ocean ResearchA U T H O R SSteffen PauschNautilus Marine Service GmbH

Detlef BelowDURAN Group GmbH

Kevin HardyDeepSea Power & Light

A B S T R A C TAll stationary and autonomous instrumentation for observational activities in

ocean research have two things in common, they need pressure-resistant housingsand buoyancy to bring instruments safely back to the surface. The use of glassspheres is attractive in many ways. Glass qualities such as the immense strength–weight ratio, corrosion resistance, and low cost make glass spheres ideal for bothflotation and instrument housings. On the other hand, glass is brittle and hencesubject to damage from impact. The production of glass spheres therefore requireshigh-quality raw material, advanced manufacturing technology and expertise inprocessing. VITROVEX® spheres made of DURAN® borosilicate glass 3.3 are theonly commercially available 17-inch glass spheres with operational ratings to fullocean trench depth. They provide a low-cost option for specialized flotation andinstrument housings.Keywords: Buoyancy, Flotation, Instrument housings, Pressure, Spheres, Trench,VITROVEX®

Introduction

When Jacques Piccard and DonWalsh reached the Marianas Trenchin 1960 and reported shrimp andflounder-like fish, it was proven thatthere is life even in the very deepestparts of the ocean. What started as asimple search for life has become overthe years a search for answers to basicquestions such as the number of spe-cies, their distribution ranges, and thecomposition of the fauna. The discov-ery of swarming snailfish at 7,700m byUniversity of Aberdeen’s (UK) Ocean-lab so far presents the culmination ofthese researches. Although the oceanshave been investigated for a longtime, the deeper depths present a chal-lenge to exploration due to the ex-treme environmental conditions thatexist there. It is totally dark, constantlycold, and the pressure is immense. Ata depth of 1,000 m, the weight onevery square centimeter is 100 kg butincreases to 1,100 kg at 11,000 m.

Still, researchers today have a suite ofstationary and autonomous instrumen-tation available for hadal observation.All these instruments have two funda-mental requirements in common:

(1) they need to have pressure-resistant housings to accommodatesensitive electronics, and (2) they needeither positive buoyancy to bring theinstrument or sampler back to the sur-face for recovery or to establish neutralbuoyancy for manned or remotely op-erated vehicles to dock and lift thepackage (Figure 1).

Advantages andDisadvantagesof Glass Spheres

Because of the compressive force ofwater pressure, the pressure case designand the material selection for buoyancyelements or pressure housings are vital.Like the crew compartment of theTrieste 50 years ago, the ideal shape isa sphere. Because of its geometry withno corners, a sphere distributes the ex-ternal forces of the water evenly over itsstructure, making it the strongest possi-ble shape. The material chosen may besteel or other metals, molded plastic,ceramics, or glass.

The use of glass is attractive in manyways. Glass has an immense strength-to-weight ratio and it is inherently cheap. Itis corrosion resistant and nonpolluting.Additionally, glass spheres are trans-parent, nonmagnetic, and electrically

FIGURE 1

Benthic lander with VITROVEX®flotation

spheres.

Winter 2009 Volume 43, Number 5 105

nonconductive. Command and con-trol of instruments, including upload-ing mission profiles or downloadingdata, may be done through the glasswith hall effect or reed switches, infra-red, or blue tooth. Radio and flash-ing light recovery beacons have beenshown to work effectively housed in-ternally. GPS, ARGOS, or Iridiumtransceivers as well as VHF radio linkspenetrate the glass without problem.Status lights and LCD displays are vis-ible to deck crews before deployment.The high-quality glass may even havebeen polished to create a viewport sec-tion for high-resolution digital camerasor sensors utilizing light. The use of ex-ternal pressure-compensated lithiumpolymer batteries, as described else-where in this issue, means the spheresneed never be opened at sea, and theuse of small vessels of opportunitybecomes more attractive. Indeed, a re-search team from Scripps Institutionof Oceanography/UCSD deployedtwo free vehicles, described below,using 17-inch VITROVEX® spheres to8,400 m (27,500 feet) from a 53-feetboat in November 2006.

As appealing as it is, glass has, how-ever, some drawbacks in that it is diffi-cult to machine accurately, it is brittle,and hence is subject to damage fromimpact and spalling. The glass mayspall when cycled. The bearing stressesunder standard connectors can causespalling at the corner of the spotfaceand the diamond drilled hole. A large4-mm-thick “flat washer” with a largerdiameter o-ring can be used to spreadout the load over a larger area. Theconnector o-ring rests on the top ofthe “flat washer,” which has a smoothfinished o-ring surface. Some under-water connectormanufacturers, includ-ing SubConn and Teledyne Impulse,have created connector bodies thatare specially adapted to glass housings.

Handling spheres at sea can benerve wracking when opening and clos-ing the fragile glass in bumpy seas. Thehemispheres take some practice to feelcomfortable moving and lifting them.A rubber bumper over the exposedglass faces brings some measure of pro-tection, but a system design that pre-cludes the need to open the sphere atsea, as described above, is preferred.The glass sphere housing requiressome skill to seal. The sealing surfacesmust be very well cleaned and free ofany grease, oil, lint, or other foreignmaterial. The low-pressure seal aroundthe equator is made with butyl rubberand wide black tape. A vacuum portis quite useful. A pocket altimetermounted to the interior is easily viewedproviding confidence the sphere issealed and not slowly leaking. Thesphere is protected in a thick wallLDPE hardhat, which also simplifiesmounting.

History of VITROVEX®Glass Flotation andInstrument Housings

All pressure housings depend ongeometry, outside diameter, wall thick-ness, and material to reach their de-sired design depth. VITROVEX® glassspheres of 10- or 13-inch diametercan withstand pressure at 9,000 or7,000 m, respectively. Larger 17-inchspheres are made to reach 6,700 m,and now to 9,000 m and 11,000 m.The flotation spheres and instrumenthousings are composed of two matedglass hemispheres that are evacuatedand locked into position by a sealantand protective tape. Once the spheresare sealed, the two hemispheres arekept together by the atmosphericpressure on land and the pressureof the water column when deployed.VITROVEX® spheres are made of

borosilicate glass 3.3 with standardizedphysical, chemical, electrical, and op-tical properties, also well known asDURAN®. This kind of glass was firstdeveloped by the German glassmakerOtto Schott in the late 19th century.Borosilicate glass is created by addingboron to the traditional glassmaker’sfrit of silicate sand, soda, and groundlime. Borosilicate glass has a very highphysical strength and very low thermalexpansion coefficient, about one thirdthat of ordinary glass. This reduces ma-terial stresses caused by pressure andtemperature gradients, thus making itmore resistant to breaking. Borosilicateglass is commonly used in ovenware,where it is known by its commercialname of “Pyrex®” (Figure 2).

As a result, VITROVEX® flota-tion spheres and instrument housingsshow very little deviation in shape evenunder the high pressure found in oceantrenches. Since two hemispheres haveto be put together to form one sphere,matching the geometries is critical. Inaddition to precision molding of theright type of glass, skilled craftsmanshipdirects the pressing of each hemisphereto exactly the same dimensions, outer

FIGURE 2

Production of VITROVEX® hemispheres re-quires high-quality raw material, precisionmolds, advanced manufacturing technology,and processing expertise to meet the challengeof ocean trenches.

106 Marine Technology Society Journal

diameter, inner diameter and wallthickness, as all the others of that size.The mating surfaces require a triplegrinding process: milling with diamondtools, manual smoothing, and manualpolishing to ensure the parting planesealing faces are honed to a precise flat-ness and finish. The congruous surfacesare so closely matched that when twohemispheres are set together, with nobutyl and tape at the parting line, anda hard vacuum is pulled, it takes a dayfor the vacuum to bleed down moleculeby molecule. Place the butyl rubber andtape on the seam, and it might takeforever. As a result of precision form-ing, VITROVEX® hemispheres of thesame outside diameter and wall thick-ness are completely interchangeableand can be replaced individually. Dur-ing assembly, they are aligned alongthe outer circumference only; there isno need to rotate the hemispheres tofind matching alignment markers. Thisis a very valuable feature when it comesto instrument housings.

Spheres can be made with a varietyof drill holes to accommodate connec-tors, feedthroughs, and a vacuum portfor connection to electronics and bat-teries inside, or releases, sensors orother packages on the outside. Withthe ability to exchange a single hemi-sphere, one can easily be exchangedby another with a different arrange-ment of drill holes.

Different sizes of glass spheres andeven cylinders provide high-pressureflotation and instrument housings op-tions to meet design requirements upto full ocean depth (Figure 3).

Further Development ofVITROVEX® Glass Spheresto Full Ocean Depth

Nautilus Marine Service successfullydeveloped 13- and 17-inch spheres with

7,000 and 6,700 m pressure rating inthe early 1990s. So it was in the natureof things to face the challenge of goingdeeper.

This development was driven byvarious scientific institutions such asScripps Institution of Oceanography/UCSD (Kevin Hardy, 2000, in col-laboration with Emory Kristof, Na-tional Geographic Society), and later,the Oceanlab from the University ofAberdeen.

“Our initial plan,” said Hardy, “wasto use the 7 km VITROVEX® spheressimply as self-buoyant housings, withexterior lights and a camera. The planchanged instantly when the deliveredspheres appeared to be high enoughquality to polish a viewport in theglass and place our camera inside. Ourfinal design placed the camera, flash,control electronics, release system, bat-teries, and recovery beacons inside asingle sphere, making deployment andrecovery a simple matter from virtuallyany size vessel. Hardy and Nautilus’Gerald Abich discussed means to mod-ify the VITROVEX® tooling to thickenthe walls for 11 km trench depths. See-ing the first of the new thicker wallglass spheres, bathyscaph TriestePilot, Don Walsh, who personallylooked out a porthole at the floorof the Mariana Trench, exclaimed,“Deep and Cheap. I like it!”

The first camera pod, DOV MaryCarol, was used successfully in theAleut ian Trench, Puer to Rico

Trench, and even modified to func-tion as a towed camera in the Sea ofCortez to confirm the presence ofbacterial mats (Figures 4 and 5)(Hardy et al., 2002).

To create these thicker wall var-iants of glass hemispheres with thesame desired precision, all productionparameters had to be redefined. Themajor challenge for the project team

FIGURE 3

Examples of VITROVEX® glass products.

FIGURE 4

Deep Ocean vehicle DOV Mary Carol, built froma single VITROVEX® 17-inch sphere, is recov-ered on the stern of Scripps Institution ofOceanography/UCSD’s R/V Sproul by Scrippsengineer Kevin Hardy in August 2003. (Photoby Emory Kristof.)


was to adjust the relation of glass tem-perature, molding, and cooling preciselyin order to keep the massive amountof DURAN® glass in the desired ge-ometry. Due to very close cooperationwith its long-time partner DURANGroup GmbH, a specialist in borosili-cate glass 3.3, Nautilus Marine Servicesuccessfully accomplished this project.

As a consequence, a new type ofVITROVEX® self-buoyant spherewith a depth rating of 12,000 m anda wall thickness of 21 mm was madefor those who want to explore eventhe deepest parts of the oceans. Amore lighter weight version with pres-sure rating of 9,000 m also becameavailable.

Use of Deep WaterVITROVEX® Spheresin Oceanography

Over the recent years, deep waterVITROVEX® spheres have becomecomponent parts of many deep oceanexplorations. The 12,000-m spherewith a wall thickness of 21 mm (Fig-ure 6) was part of the ascent systemfor Oceanlab’s Hadal-lander. A more

detailed description about this applica-tion is given by Alan J. Jamieson in aseparate article in this journal.

Elsewhere, a team of deep oceanbiologists from Scripps Institutionof Oceanography/UCSD directed byDr. Douglas Bartlett tested a 17-inchVITROVEX® 9,000 m rated spherewith multiple feedthroughs in Deep-Sea Power & Light’s 20-inch pressurechamber in June 2009. The sphere wasbeing qualified for operation in thePuerto Rico Trench, where depthscan reach 8,400 m. The sphere was suc-cessfully taken to 12,750 psi, equiva-lent to 8,750 m. The sphere is partof a two-sphere free vehicle that gath-ers 60-L water samples from the ben-thic boundary layer 2 m above thetrench floor layer along the axis of anocean trench. A sediment sampler de-ployed from the lander collects surfacesediments for other microbial studies.“The test was particularly useful inconfirming the integrity of the spherewhich experienced someminor spallingduring its deployment to 8,400 m lastyear,” said the researchers (DeepSeaPower & Light, 2009) (Figure 7).

The French Company SERCELuses the VITROVEX® 9,000m spheresfor their MicrOBS_Plus (Figure 8)Ocean Bottom Seismometer (OBS).An OBS is designed to record seismicwaves in the seafloor generated by

earthquakes, or artificial sources, bymeans of hydrophones and geophones.An OBS is deployed from a ship andfree falls through the water column,

FIGURE 5

This image is taken through a viewport polishedinto the 7-km sphere of DOV Mary Carol at adepth of 1.4 km off San Diego, CA, June2003. Similar quality images have been ac-quired with thicker 12 km spheres in oceantrenches.

FIGURE 6

VITROVEX® hemisphere for full ocean depthwith all wall thickness of 21 mm.

FIGURE 7

Double VITROVEX® spheres provide lift for afree vehicle ocean trench water sampler builtby Scripps Institution of Oceanography/UCSDin 2006. (Photo by Kevin Hardy, Scripps In-stitution of Oceanography/UCSD).

FIGURE 8

MicrOBS_Plus OBS from Sercel.


landing on the seafloor. Upon comple-tion of the mission, an acoustic signal issent to the instrument to release an an-chor weight. The OBS then floats tothe surface and recorded data canbe uploaded. In such applications, theVITROVEX® sphere provides buoy-ancy as well as pressure protection atonce.

ConclusionGlass spheres are indispensable in

underwater research for both flotationand instrument housings. They maybecome even more important in thefuture. Ongoing analysis at DOERMarine in the United States, with theaid of VITROVEX® glass, provide aglimpse into the future where humanoccupants may utilize a fully spherical,glass-hulled manned submersible witha panoramic view. That is probablysomething Jacques Piccard and DonWalsh would have liked to have seen50 years ago.

ReferencesDeepSea Power & Light. 2009. 17-inch glass

sphere tested in DeepSea’s 20-inch Pressure

Chamber. The DeepSea Scrolls, 2(4).

Hardy, K., Olsson, M., Yayanos, A. A., Prsha,

J., Hagey, W. 2002. Deep Ocean Visualization

Experimenter (DOVE): Low-cost 10 km

Camera and Instrument Platform, Oceans 2002

Conference Proceedings, MTS/IEEE-OES,

Washington, DC.


P A P E R

Flotation in Ocean Trenches Using HollowCeramic SpheresA U T H O R SSteve WestonMark OlssonRay MerewetherJohn SandersonDeepSea Power & Light

A B S T R A C TSpherical flotation units of 99.9% Al2O3 ceramic have been successfully pro-

duced by DeepSea Power & Light for application to ocean trench systems, suchas the Woods Hole Oceanographic Institution (WHOI) hybrid remotely operatedvehicle (HROV) Nereus and other high-performance systems requiring maximumbuoyancy with minimum air weight. WHOI successfully operated their HROV in theMariana Trench Challenger Deep in Summer 2009, scooting across the trench floorfor a total of 11 h at 36,000 feet (11,000 m). More than 1,750 3.6-inch (91.45 mm),OD seamless hollow ceramic spheres, each generating 0.6 lb (272 g) of lift, providedNereus its buoyancy. The spheres, with a 0.34 weight/displacement ratio, withstoodproof testing to 30,000 psi (207 MPa), 1,000 h of sustained pressurization to25,000 psi and 10,000 pressure cycles to 20,000 psi (138 MPa). In addition, eachof theWHOI spheres withstood 15 h at 18 ksi static pressure hold.When encased in a0.2-inch thick buoyant elastomeric boot, they withstood impact on a concrete floorfrom a 6-foot elevation. An extensive quality assurance (QA) procedure is applied to100% of manufactured spheres, with strict adherence to tight dimensional and thick-ness specifications as well as pressure test acoustic emission criteria (Figure 1).

DeepSea Power & Light has additionally demonstrated the process for castinglarger alumina ceramic spheres with an 8.6-inch (218.4 mm) outside diameter forthe whole range of ocean depths from 10,000 feet (3000 m) to 36,000 feet(11,000 m). The larger spheres were successfully used offshore by Scripps Insti-tution of Oceanography/UCSD in summer 2005 in an experimental free vehiclesediment sampler that impacted the seafloor at 2 m/s at a water depth of2,200 m, dropped a weight, then rebounded to the surface with its cargo ofsediment.

Background

To lift a payload while submerged,all underwater vehicles require buoy-ancy provided either by the pressurehull, flotation units attached to thehull, or both. Flotation for deep sub-mergence vehicles has traditionallybeen made from syntactic foam,glass, or ceramic spheres or, in thecase of the bathyscaph Trieste, lighter-than-water aviation gasoline. Syntac-tic foam, a composite of plastic andglass microspheres, produces buoy-ancy from the displacement of themyriad glass microspheres embeddedin a plastic matrix. The buoyancy ofthe foam is a function of the wallthickness of the glass spheres andof their packing density in the plasticmatrix. By screening the glass spheresfor size and wall thickness, manufac-turers can tailor the pressure resistanceof the syntactic foam. Utilizing thisprocess, industry has developed syn-tactic foams for the whole range ofocean depths. The factor limitingtheir buoyancy is ultimately the pack-ing density of microspheres in theplastic matrix since the plastic binderdoes not provide any buoyancy.

Glass or ceramic macrospheres maybe held in place in a framework madeof lighter than water plastic. The sizes

of spheres and their pressure re-sistance can be tailored to the require-ment of the vehicle. The crucial itemsin maximizing their pressure resis-tance are material with high compres-sive strength, absence of joints, andminimum deviation from perfectsphericity and uniform thickness.

The presence of joints introduceslocal tensile stresses causing glass or ce-ramic spheres to fail under long-term,and/or cyclic pressurizations at a lowerpressure than it would in the absenceof joints (Stachiw et al., 1993). The

lack of a fabrication processes thatwould deliver seamless spheres withuniform sphericity and shell thicknesswas a major stumbling block to achiev-ing maximum buoyancy of ceramicspheres of utmost reliability.

A solution was found in 1964 atCOORS PORCELAIN with the de-velopment of a casting procedure toallow production of seamless hol-low 10 inch spheres with a nominaldepth rating of 20,000 feet (Reardon,1969). However, because of the largevariation in structural performance


between individual spheres, they wereconsidered too risky for application onmanned submersibles. As a result, theirshare of the market decreased to thepoint where the fabrication costs be-came unprofitable and by the late1960s COORS PORCELAIN closedtheir production for good.

It required the appearance ofROV ’s and AUV ’s for deep ocean ex-ploration to renew the demand for ce-ramic floats with buoyancy at depthsuperior to any syntactic foam avail-able on the market. Woods HoleOceanographic Institution (WHOI)used its hybrid remotely operated vehi-cle (HROV) vehicle development asa context to push the design limits ofcurrent ocean engineering. Not satis-fied with the buoyancy provided bysyntactic foam for 36,000 feet (11 km)service, WHOI looked to find a sup-

plier capable of manufacturing ceramicseamless spheres for 36,000 feet(11 km) service. This paper focuseson the design, fabrication, structuralperformance, and quality control(QC) of 3.6-inchOD spheres suppliedto WHOI by DeepSea Power & Light(DSPL).

IntroductionBefore the spheres could be incor-

porated into the 11-km HROV underconstruction by WHOI, several issueshad to be resolved satisfactorily topreclude implosion in service. Implo-sion even of a single sphere may initi-ate sympathetic implosions of otherspheres on the vehicle and the result-ing loss of buoyancy would sink thevehicle. To preclude implosion in ser-vice, sufficient care had to be exercisedover the design, fabrication procedure,quality inspection, and performancetesting. With proper attention to de-tails, the ceramic spheres should beas reliable in service as are the acrylicplastic spheres serving as the pressurehulls on manned submersibles.

DesignThe design criterion selected for

the 3.6-inch OD spheres was a safetyfactor of two based on the 16,500-psi(113.8-MPa) pressure specified byWHOI for its 11 km HROV with36,000 feet (11,000 m) service depth.The same safety margin had to applyboth to the magnitude of stresses aswell as elastic stability at critical pres-sure. To achieve the 100% safetymargin, the average shell thickness ofthe spheres was calculated to be0.060 inches (1.5 mm) using Equa-tion 1 for prediction of material failure(Roark, 1965) and Equation 2 for pre-

diction of buckling (Roark, 1965;Krenzke and Charles, 1963):

EQ 1 : pcr ¼ δðRo3 − Ri3Þ 1:5×ðRo3Þ

EQ 2 : pcr ¼ K × E×ðt2=Ro2Þ

Where E = 56,000,000 psi, modulusof elasticity, δ = 550,000 psi, compres-sive strength of 99.9% Al2O3, and K =0.56 has been derived by Dr. Stachiwfrom destructive testing of over thirty10-inch OD ceramic seamless spheresfabricated by COORS PORCELAINfor the Naval Ship Research and De-velopment Center in 1969 (Reardon,1969).

The calculated critical pressures of34,844 psi by buckling and 35,209 psiby material failure were high enoughto allow +0.01-inch variation in localwall thickness without reduction ofcalculated critical pressures below33,000 psi mandated by the SF = 2requirement.

Validation ofDesign Criteria

It has been experimentally shownthat the implosion pressure underlong-term and/or cyclic pressurizationsis significantly less than under short-term pressurization because ceramicunder tensile strain exhibits time de-pendent failure. Although the loadingon the spheres under hydrostatic pres-sure is compressive, some tensile strainsare always present at microscopic dis-continuities in the material causing itto fracture under time dependant staticor cyclic load application.

The selected SF = 2 based on short-term destructive testing is more thanadequate to provide a safety marginfor a single service dive to design pres-sure. Whether it is adequate to providea safety margin for long-term and/or

FIGURE 1

Engineers at WHOI demonstrate the tough-ness of DSPL’s jacketed hollow ceramicspheres they use to provide lift at extremepressures for their deep diving HROV, Nereus.(Photo by Tom Kleindinst, WHOI).


cyclic pressurizations to design pres-sure, typical of ROV and AUVs, wasto be experimentally validated.

The validation of the 100% short-term safety margin focused on generat-ing experimental data on the static andcyclic fatigue of DSPL’s 3.6-inch OD99.9% Al2O3 spheres.

A minimum operational require-ment of the ROV/AUV is assumedto be 10,000 h of static and 1,000 cy-clic pressurizations to service depth of36,000 feet (11 km). The intention ofthis testing is to validate whether thestatic and cyclic fatigue life of the3.6-inch OD spheres with 0.06-inchwall thickness could meet this criteria.

The classic approach to generationof this data set is to subject severalspheres to sustained design pressureloading until they implode. The aver-age length of time to implosion wouldbe considered their static fatigue life.By the same token, their cyclic fa-tigue life can be formulated by pres-sure cycling several spheres to designpressure loading until they fail. Thenumber of cycles prior to implosionwould be considered their cyclic fa-tigue life.

Because the classical approach re-quires the utilization of pressure vesselsfor thousands of hours, it is not utilizedfrequently. Instead, the spheres aretested at pressures above design pres-sure, substituting the pressure differ-ential above design pressure for time.When the durations of sustained load-ing prior to implosion of pressureabove the 16,500 psi (113.8 MPa) de-sign pressure are analyzed, one can ex-trapolate from it the static fatigue lifeat 16,500 psi (36,000 feet/11 km inservice depth). [8] This was the ap-proach taken by DSPL for predictionof static and cyclic fatigue life for the3.6-inch OD spheres with 0.06-inchwall thickness.

Discussion of DesignValidation Results

The test results generated duringthe experimental design validationphase fall into three categories: criticalpressures under short-term pressuriza-tion, sustained pressurization, and cy-clic pressurization. Each one of thesetest categories plays a different role inthe validation of chosen sphere de-sign, that is, thickness of shell selectedfor the 16,500 psi (113.8 MPa) designpressure.

It is an accepted practice in the in-dustry to rely solely on short-termnon-destructive proof tests to qualifya flotation unit for a given pressurerating. In the opinion of the authors,this is not sufficient, unless a pressuretest program utilizing destructiveshort-term, sustained pressure and cy-clic pressurizations has already vali-dated the design of the sphere. Onlyafter such a design validation programhas been successfully completed cannon-destructive short-term pressuriza-tion serve as QC and QA acceptancetests.

The objective of short-term destruc-tive tests in the design validation pro-gram is twofold; it serves as a checkon the calculated magnitude of criticalpressure based on Equations 1 and 2for prediction of implosion either bymaterial failure, or elastic instability,and as a QC tool on the uniformityof structural performance of mass pro-duced spheres. For the spheres de-signed on the basis of 100% safetymargin, the short-term critical pressurewas expected to be 35,200 psi if theimplosion was caused by material fail-ure at 550,000 psi compressive stresslevel and 38,400 psi if the implosionwas triggered by elastic instability. Un-fortunately, pressure vessels were avail-able only with 30,000 psi capabilityand thus all the short-term pressuriza-

tions were conducted only to 30,000 psilevel. However, by extrapolating thestatic critical pressures of spheres withweight <139 g, the critical pressureof 139 g spheres has been predictedto be >35,000 psi. Since testing to30,000 psi stresses the material onlyto 85% of the calculated materialshort-term strength and 78% of buck-ling pressure, any failure of a sphere at30,000 psi would be an indication thatthe structural performance is inade-quate caused either by shortcomingsin material quality or shell construc-tion. In either case, it would not be arepresentative example for long-termor cyclic pressure testing. All spheresmeeting the technical specification re-quirements of weight, minimum shellthickness, and sphericity passed short-term (<2 s) pressurization to 30,000 psi.It can therefore be concluded that theirstructural performance exceeds 85%of design strength.

The objective of long-term destruc-tive tests in the design validation pro-gram is to establish by experimentalmeans the static fatigue life of thespheres at 16,500 psi design pressure.This was to be established by extrapo-lation of sustained pressure test resultsat 30,000 and 25,000 psi. Pressureshigher than the design pressure werechosen to accelerate the implosionof spheres under sustained loading.Some tests were also conducted atother pressures in pressure vessels ofopportunity.

The number of tests was not suffi-ciently large to provide an adequatenumber of data for statistical analysis.It was, however, large enough to estab-lish confidence in the safe performanceof spheres at design depth during amission of the WHOI 11-km HROVunder extended duration. The results in-dicate that at 16,500 psi (11-km depth)design pressure, the static fatigue life is


in excess of 10,000 h, providing ade-quate time for more than 400 missionsof 24-hour duration (Weston et al.,2005).

The objective of cyclic pressurizationdestructive tests is to establish the cyclicfatigue life of the spheres under designpressure. Since the spheres are of seam-less construction there was no op-portunity to develop cracks at theequatorial joint, typical of spheres as-sembled from hemispheres. It isknown from other studies conductedon ceramic and glass specimens thatthe intrinsic cyclic fatigue life of thosematerials under cyclic compressiveloading is large enough to be beyondthe engineering design scope of flota-tion units and housings for oceano-graphic service.

Only if mechanical joints are pres-ent in ceramic pressure vessels for anoceanographic applications does thecyclic fatigue life become the control-ling factor of their service life.

The cyclic pressure testing con-ducted on the seamless spheres has,on the other hand, demonstrated thattheir cyclic fatigue life at compressivemembrane stress of 478,000 psi is>5000 cycles and under compressivestress of 337,000 psi is >15,000 cycles.Needless to say, at design stress of256,000 psi generated by 36,000 feetdesign depth, the cyclic fatigue life ofspheres with 0.06-inch thick wall willexceed the above values by a factor ofat least 2.

The service fatigue life requirementfor 11 km HROV is less than 1000dives to 36,000 feet design depth.This generates 256,000 psi membranestress in the shell of the sphere. The ex-perimentally demonstrated cyclic fa-tigue life is in excess of 5000 cycleswith 478,000 psi membrane stress.This surpasses by a wide margin thespecified service fatigue life require-

ment for the 11 kmHROV. Althoughthe typical duration of the pressure testcycle was less than 4 s and the durationof a service dive is on the order of 10 to20 h, the effect on the cyclic fatigue lifeis the same. Published data indicatethat it is the cumulative time underload rather than the number of cyclesthat define the cyclic fatigue life ofbrittle materials (Shand, 1958). Sincethe demonstrated 6 × 104 s cumulativeduration of 15,000 pressure cycles at337,500 psi membrane stress is lessthan the demonstrated static fatiguelife of 36 × 104 s at the same pressureon ceramic spheres, the effect of cyclingcan be disregarded so long as the staticfatigue life at design depth exceeds thecumulative time under pressure duringpressure cycling.

FabricationThe seamless spheres were fabricated

by roto-molding in spherical moldsassembled from well-fitted plasterhemispheres to meet the technical spec-ification developed by Dr. Jerry Stachiwfor 3.6-inch OD ceramic spheres with16,500 psi pressure rating.

QA ProgramTo minimize departure in struc-

tural performance from the test datagenerated during validation of design,a strict QA program was applied to theproduction of 3.6-inch OD ceramicspheres for service on theWHOI vehi-cle. Main features of the QA programincludea. checking of weight for confor-

mance to technical specification;b. checking for minimum thickness

for conformance to specification;c. checking of diameter and diamet-

rical run-out for conformance totechnical specifications;

d. visual inspection for surface flawsand other anomalies; and

e. weeding out unacceptable struc-tural deviations by subjectingeach sphere to two pressure cycles,first to 30,000 psi, followed bya second one to 20,000 psiwhile monitoring for acousticemissions.The acoustical testing was accom-

plished by the use of a custom-builtpressure chamber acoustically instru-mented to detect sounds emanatingfrom within.

Discussion of QAProgram Results

A group of spheres was made to theTechnical Specifications (Table 1).A sample batch of 20 spheres wasthen selected and subjected to thisQA program. Of the 20 samples,2 were rejected because of surfaceflaws, providing an overall 90% passrate in the visual screening. With thepotential for sympathetic implosion,however, any failures are unaccept-able and DSPL acoustically tests100% of its spheres. This proof testsubjects each sphere to 30,000 psiwhile monitoring acoustic emissions.On average, an additional 25% of ce-ramic spheres do not pass acousticemission testing.

FindingsDSPL’s 3.6-inch alumina ceramic

spheres with a 0.06-inch wall meetthe design and service requirementsof flotation for 36,000 feet (11 km)service; they do not implode un-der short-term proof pressure to36,000 psi (207 MPa) and 10,000dives of 10,000 h cumulative dura-tion to 35,000 feet (11 km) designdepth.


The QA program developed forthe production of these spheres as-sures that the spheres delivered tothe customer for mounting on theocean trench vehicles will perform inthe same manner as the spheres testedin the design validation program.This is accomplished by checkingeach sphere for conformance to theTechnical Specification (i.e., weight,

diameter, thickness of shell) andstructural performance requirements(i.e., proof testing twice to 30,000 psiwhile monitoring acoustic emissions)(Figure 2).

ConclusionDSPL has succeeded in developing

an economical mass production pro-cess for roto-molding alumina ceramicspheres whose dimensions and struc-tural performance are repeatable,making them interchangeable in appli-cation. At the present time the produc-tion process is being applied only to3.6-inch OD spheres with 0.06-inchwall thickness and their perfor-mance experimentally verified for36,000 feet (11 km) service. Sphereswith 3.6-inch OD but lesser wallthickness are also being produced bythe same manufacturing process andequipment for structural evaluation.

ReferencesKrenzke, M. Charles, R. 1963, September.

The Elastic Buckling Strength of Spherical

Glass Shells. David Taylor Model Basin Re-

port 1759.

Reardon, E. 1969, April. Exploratory Tests of

Alumina Spheres under External Pressure.

Naval Ship Research and Development Center

Report 3013.

Roark, R. J. 1965. Formulas for Stress and

Strain. New York: McGraw Hill Book Co.

Shand, E. 1958. Glass Engineering Hand-

book. New York: McGraw Hill Book Co.

Stachiw, J. D., Kurkchubasche, R. R.

Johnson, R. 1993, August. Structural Perfor-

mance of Cylindrical Pressure Housings of

Different Ceramic Compositions Under

External Pressure Loading: Part I. Isostatically

Pressed Alumina Ceramic, NOSC Technical

Report 1590.

Weston, S., Stachiw, J., Merewether, R.,

Olsson, M., Jemmott, G. 2005, September.

Alumina Ceramic 3.6-in Flotation Spheres for

11 km ROV/AUV Systems. Oceans 2005

Conference, Washington, DC. Available

online at: http://deepsea.com/pdf/articles/

Alumina%20Ceramic%20Spheres.pdf.

FIGURE 2

After four years of design and construction,Nereus took its first plunge in deeper watersduring a test cruise in December 2007 off theWaianae coast of Oahu, Hawaii. Because Nereuswas a little tail heavy, additional spheres wereadded in red mesh bags for trim. The one-of-a-kind vehicle can operate either as an auton-omous, free-swimming robot for wide-areasurveys, or as a tethered vehicle for close-upinvestigation and sampling of seafloor rocksand organisms. (Photo by Robert Elder,WHOI).

TABLE 1

Technical specifications.

a. Slurry composition: 99.9% Al2O3

b. Weight: 140 ± 1 g

c. Minimum thickness: 0.06 ± 0.01 inches

d. Outside diameter: 3.60 ± 0.05 inches

e. Diameter variation on each sphere: ±0.03 inch max

Typical Characteristics of Roto-molded 3.6 in Ceramic Spheres for 11-km Service

Maximum Minimum Average

Weight (g) 140.761 139.128 139.901

Diameter (in) 3.629 3.565 3.597

Thickness (in) 0.065 0.052 0.058


P A P E R

Modular Design of Li-Ion and Li-PolymerBatteries for Undersea EnvironmentsA U T H O RDavid A. WhiteSouthwest Electronic Energy Group

A B S T R A C TLi-Ion chemistry is ideal for undersea environments. The cells are sealed and

do not outgas, and the polymer versions can withstand pressures greater than10,000 psi. This combination results in a battery that is easier and safer to useand one that does not require heavy, expensive pressure vessels.

Recent advances in electronic control of the Li-Ion battery and new modular de-sign concepts for construction of complex battery systems have resulted in batterysystems that are more robust, more flexible, longer lived, easier to charge andmain-tain, and safer than their lower density counterparts. These new Li-Ion battery sys-tems can be designed to deliver this energy at high voltages and high currents.Electronic charge control within the battery system allows charging by direct con-nection to power supplies or constant power sources such as fuel cells and solarpanels.

The modular design concept for Li-Ion and Li-Polymer battery systems are pre-sented with an emphasis on construction for undersea applications. Key to themod-ular battery system design concept is the ability to electronically balance all the cellswithin the battery system automatically without operator intervention. Two differentmethods are described, which show how electronic balancing of all the cells withinthe battery system is accomplished. Examples of production battery systems al-ready in service are shown, and systems under development are provided.Keywords: Modular Lithium-Ion Undersea Batteries

The battery industry is on the vergeof a significant growth cycle in large for-mat lithium-ion (Li-Ion) battery systemsdue to expected demand for electric landvehicles. Important to this growth iswhat was once thought of as a detrimentof the Li-Ion chemistry—that it requiresmonitoring and control electronics forsafety and for reliability. Engineers areturning this detriment into an advantageby using intelligent electronics to makebattery systems that have capabilitiesthat would not be practical, or even pos-sible, without these electronic tools.While the land version of these batterysystems is not necessarily suited for un-dersea environments, the same batterychemistry and electronics can be adaptedfor hadal zone regions deeper than 6 km.This article will show how a new conceptof modularly designed Li-Ion and Li-Polymer batteries can be incorporatedinto marine vehicles that are not in thehigh production mainstream and thathave the unique performance require-ments of operation in a freezing and hor-rendously high pressure environment.This new battery system developmentmethodology utilizes battery modulesto construct complex battery systems.

Challenges of HighPressure on Batteriesand Electronics

People familiar with undersea bat-teries using the conventional lead-

acid or nickel-cadmium chemistriesknow that even though the name ofthe cell or battery may contain theterm “sealed,” these chemistries arenot really sealed. They have to breath,and when they are being fully chargedthey have the nasty characteristic ofgiving off highly flammable and ex-plosive gases. Therefore, dischargecan be done in a sealed environmentbut full capacity charging can onlysafely be done in an unsealed and avented environment. Where thesecells cannot be vented (as in operationin an oil bath), it is possible to under-charge them to prevent outgassing,but this is at the expense of reducedlife. The consequence, for safety rea-sons and when housed in a pressure

vessel, is these batteries require thepressure vessel to be unsealed andvented during charge and resealedfor use, with the nagging knowledgethat multiple unseal and reseal cyclescan result in leaks (Figure 1).

Thus, a restriction on underseamissions using conventional recharge-able batteries is that the battery cannotbe charged during the subsurface mis-sion. This limits mission time to theenergy capacity that can be carried onthe exploration vehicle. If the batterycould be charged, a low current tethercould be used to maintain capacity ofthe battery system assuming its energyoutput is a mixture of low power ob-servation current and high power cur-rent bursts for vehicle transient and


positioning. Depending on the mis-sion, this could significantly extendmission time while keeping batterypayload at a reasonable level. Theproblem of needing a significantlyhigher energy density battery and oflonger or potentially continuousmissions (manned or unmanned) is asevere restriction for conventional re-chargeable battery chemistries.

Rechargeable lithium-ion (Li-Ion)cells and batteries, introduced in the1990s, have matured and promise re-duction or even removal of the re-strictions of conventional batterychemistries. The rechargeable Li-Ioncell is not only two to four timesmore energy dense than other re-chargeable chemistries, it is also trulysealed and can be charged and dis-charged without outgassing. The onlyproblem is that the chemistry is very

sensitive to any contamination. If thecell’s seal is broken, foreign materialsuch as water or oils render the cell in-operative and may actually cause it tooutgas just prior to failure. For this rea-son, cylindrical Li-Ion cells that workfine within a pressure vessel cannotwork at hadal zone pressures in oil sub-mersion because there are air pocketswithin the metal encased cells. Highoutside pressure can therefore deformcylindrical cell cases and burst cellseals with resulting oil contaminationand cell damage. However, as theLi-Ion technology maturity has contin-ued, a new packaged form of the samechemistry cell has been developed,called Lithium-Polymer (Li-Polymer).The Li-Polymer cell contains a Li-Ionchemistry that is housed within asealed foil pouch. The pouch is vacuumsealed, which removes almost all airpockets.When this cell is correctly con-structed, it can be submerged in oil orflexible potting material. Charge anddischarge cycling of cells has been testedat and above hadal zone pressures of10,000 psi. The cell does expand andcontract during charge and dischargecycling. Expansion and contraction vol-ume changes are limited to 1% to 3%and, like hadal zone amphipods, inter-nal and external pressure equalizationallows this normal “breathing” functionwithout damage to the cell. The diffi-culty presented by these new Li-Ionchemistries is that they require sophisti-cated electronics for monitoring, forcharge control, for discharge control,and for balancing functions. Can thesenecessary electronics survive hadal zonepressures?

The majority of electronic compo-nents and integrated circuits usedtoday are encapsulated in epoxy. Thisencapsulation typically allows thesedense, complex electronics to be sub-merged in oil and exposed to crushing

hadal zone pressures. However, not alltypes of electronic components can beused; for instance, any electronic com-ponents that contain air pockets suchas electrolytic capacitors can be dam-aged by hadal zone pressures. Interest-ingly, the integrated circuits thatconform to stringent military specsand that have traditionally been usedin very high reliability military applica-tions are almost exclusively housed insealed ceramic chip carriers. These ce-ramic chip carriers contain air pocketsunder thin metal lids that will collapseat high pressures and therefore are dis-allowed for hadal zone environments.In fact, any sealed electronic compo-nent is suspect since sealed or pottedcomponents can contain trapped airor vacuum spaces. Since electronicscomponents are almost never specifiedfor operation at pressure extremes, it isgood practice to test finished circuit as-semblies at pressure extremes to verifythere are no component problems.

Having designed the electronicscircuits and the cell assembly, ameans to uniformly distribute externalpressure to the assembly must be ac-complished. Oil encapsulation is anideal way to uniformly distribute exter-nal pressure and to fill air spacesbetween components and cells. How-ever, oil can allow movement of thesubmerged parts that may be damagedby differing orientation or ship-boardshock and vibration. Semi-firm pot-ting tends to be more resistant to un-controlled orientation, shock, andvibration. However, if componentsare potted, much care is required to se-lect flexible potting and to guaranteethat the potting fills all potential airpockets. This results in componentorientation during the potting process,and the potting process itself, becom-ing critical. Finally, with oil or pottingencapsulation, there is a necessity to

FIGURE 1

Trieste’s pressure compensated batteries areseen in two of the four external battery boxeswith the lids removed. Batteries are overfilledwith electrolyte in riser pipes, then the boxesare filled with oil. A compensating system pro-vides additional fluid to the interior as pressureincreases. Also seen are two of Trieste’s fivepressure compensated propulsion motors,plus the emergency ballast hopper release.(Photo: U.S. Navy, courtesy John Michel).


seal the battery and the electronicsaway from salt water. This is typicallyachieved using housings, which con-tain flexible bladder seals that allowfor the finite compressibility of oilsand potting materials at the extremehadal zone pressures.

Li-Ion Safety IssuesA high hurdle to overcome in a lith-

ium chemistry battery system, wherethe battery energy density is manytimes higher than with previous chem-istries, is safety. Designing a safe Li-Ionbattery requires experience and a sig-nificant design effort. Safety is associ-ated not only with use of the batterybut also in transportation of the battery.When the design effort is completed,its safety must be tested. Two organi-zation types are involved in regulatingsafety of lithium chemistry batteries:transportation regulation organiza-tions and military organizations.

The transportation regulations aresomething of a moving target becausethey are changing almost continuously.However, most countries, includingthe U.S. Department Of Transporta-tion (DOT), have settled on a com-mon test requirement for lithiumchemistry batteries transported viaair, land, or sea. This common test re-quirement is the UN Manual of Testsand Criteria commonly known as T1through T8 tests. The UN tests forbattery assemblies containing multi-ple battery cells require 16 to 24 com-pleted battery assemblies. The teststypically irreversibly damage or destroyabout half of these batteries and stressor use a portion of the cycle life in theother half. If the battery is large and ex-pensive, these tests can result in enor-mous capital expenditures both forlabor and for material. If the quantityof batteries produced is not very high,

the cost of these tests can kill lithiumbattery development projects.

The military regulating organiza-tion for undersea battery systems in theUnited States is the U.S. Navy. TheU.S. Navy has developed a safety hand-book, NAVSEA S9310-AQ-SAF-010,which defines both assessment methodsand destructive tests that must be per-formed on all lithium chemistry bat-teries used in, or transported on, U.S.Navy vessels. The assessment requirescalculation and screening by safety en-gineer experts. The tests are designedto cause the destruction of the batteryby high heat to determine the extent ofpotential damage that can result fromthe battery releasing its energy via eitherextended or violent battery disassem-bly. A safety determination is made byboth the assessment and the destructivetests as to the potential for endangeringpersonnel and the estimated cost of po-tential property damage. Fortunately,the destructive test does not require alarge quantity of test batteries. Never-theless, both assessment and destructivetesting are a significant expense for alarge battery system especially whereproduction quantities are not large.

Battery Size Versus Safety,Reliability, Availability,and Maintenance

How to resolve the safety problemthat can result from the high energypotential of a large battery systemand the safety testing expense of alarge battery system is a significant hur-dle. However, this is not the only hur-dle. A large battery system that mustoperate in an extreme undersea envi-ronment can be particularly unforgiv-ing should there be a componentfailure. Personnel danger, propertyloss, down time, mission failure, andsignificant maintenance expense are

real risks in a large battery system.The system designmust provide for re-duction of personnel danger, propertyloss, down time, mission failure, andmaintenance expenses.

Personnel danger can be reduced ifsafety is increased by using smaller bat-teries. Battery safety test costs are lowerif the battery is smaller. Property loss isalso reduced if the battery is smaller.Mission failure is reduced if the batterysystem has built in redundancy. Main-tenance expenses and down time arereduced if failed components are smaller,less expensive, and easy to replace.

It is evident that the challenge ishow to build a large battery systemusing small, identical, easily replace-able component parts that work in acoordinated fashion, that can be indi-vidually safety tested, and that are con-structed in situ in an arrangement thatis inherently redundant. This is a tallorder. However, there is a design con-cept for a Li-Ion battery that haspotential for meeting all of theserequirements—battery modularity.

Battery ModularityConcept

Battery modularity design method-ology is the construction of a complexrechargeable battery system using se-ries and parallel combinations of iden-tical, independent battery modules.Each battery module is a separable,self-contained, rechargeable battery of aconvenient size for on-site constructionof multiple battery system applicationsand for meeting DOT requirementsfor transport safety.

A predecessor to modular batteryconstruction concept is shown inFigure 2. Figure 2 is a photograph ofa large, 25.9 V, 356Ah Li-Ion battery.This battery, constructed for AppliedResearch Labs, utilized 36 battery


modules. Fourmodules were built intoa cylindrical layer and nine layers werestacked on top of one another. Themodules each had simple pack-protectcircuits to prevent overcharge, over-discharge, and overcurrent. The mod-ules were not separable, did notcontain cell balancing or module bal-ancing, and did not contain built incharge control. The battery had to becharged using a specially designedLi-Ion charger. Since this battery wasconstructed using cylindrical cells, ithad to be installed in a pressure vesselto maintain it at a nominal 1 atmo-

sphere pressure during use at depth.The battery did not have to be un-sealed during charging. Charging wasdone on the surface with the batterysealed within its pressure vessel.

Today’s modularity design method-ology utilizes much more sophisticatedmodule electronics. It does not requireunique chargers for the battery system.Instead, it relies on the battery modulehaving a means of internal charge con-trol that allows it to be charged frommultiple energy sources such as powersupplies, solar panels, fuel cells, or com-binations of these. A battery systemconstructed from these modules hasthe capability of using these multipleenergy sources to charge the whole bat-tery system while deployed.

Figure 3 is a smaller battery packconstructed using Li-Polymer cells.This battery pack, built for FMCTechnologies, Inc., utilizes a four-battery module section housed in aquarter cylinder case. Each one of thesequarter sections is potted. The batterysystem contains eight of these sections.Although the four modules are notseparable, the battery sections are sep-arable. Each section is mounted into asmall pressure equalization housingcontaining pressure equalization fluidand a pressure equalization bladder.

The system has a low current powertether that is capable of slow chargingthe battery pack to maintain it for con-tinuous mission utilization. This bat-tery system has been tested at 10,000 psiwhile performing low current chargeand high current discharge.

Figure 4 is a schema of a proposednew battery system for the Alvinmannedsubmarine at Wood’s Hole Oceano-graphic Institute. This battery system isa large 47.2- to 56.6-kWh battery systemconstructed from 64 rechargeable andreplaceable battery modules. Eight mod-ules are series connected into an eight-series section of modules that areseparated from one another by idealOr’ing diodes. The Or’ing diodes pre-vent the failure of a battery section fromaffecting other battery sections, thusproviding redundancy of each section.

The system shown can be charged at32 kW and discharged at 64 kW. TheAlvin is not tethered; therefore, the bat-tery system is surface charged prior to thesubsurfacemission. Full recharge time inthis instance is as fast as 2–4 h or can beslower depending on the constant volt-age, constant current power supplyused. Since the Alvin power require-ments are 48 kW, this system can runat full powerwith asmany as two 8-seriessections (16modules) disabled. The bat-tery system is sized so that two of the bat-tery systems shown can be attached tothe Alvin for a total capacity of wellover 100 kWh. Not shown is anRS-485, Modbus computer interfaceinto each module. The computer in-terface will be utilized by the Alvin tomonitor and control each battery mod-ule and the whole battery system.

Battery ModuleAdvantage Summary

Advantages of constructing largebattery systems using battery modulesinclude:

FIGURE 2

Early version of a modularly constructed bat-tery pack.

FIGURE 3

Illustration of a Li-Polymer battery pack con-taining four battery modules.


1. extreme flexibility of battery sys-tem design,

2. fast development,3. cost reduced DOT testing,4. increased safety in handling and

shipping,5. lower assembly costs,6. lower repair and replacement costs,7. lower inventory costs, and8. improved time to repair and system

availability.

Battery ModuleRequirements

Construction of dissimilar batterysystems using a multiplicity of thesame battery module requires consid-erable foresight into the battery mod-ule design. The following is a list oftypical requirements:1. fast and easy maintenance;

2. battery module replacement at anystate of charge;

3. internal charge control;4. configurable for distinctly different

applications;5. high battery module reliability;6. programmable architecture;7. support for centralized status mon-

itoring and remote control;8. support for display of state of

health, capacity, charge status,etc.;

9. chemistry agnostic; and10. the key requirement: a means to

balance all cells and all batterymodules in the battery system.

Why Balancing Isthe Key Requirement

Modern Li-Ion cell chemistries areremarkably robust in their ability to

maintain balance. Nevertheless, fieldreturn data on high series count bat-teries support the need for a robust bal-ancing capability for complex batterysystems. For high cell count batterysystems, battery pack unbalance is thenumber one reason for pack failure.To understand why, consider thefollowing:1. The likelihood of imbalance in-

creases with the number of seriesconnected cells.

2. A larger battery pack has a greaterlikelihood of portions of the packbeing at different temperatures.

3. Pack imbalance can be caused bydifferential leakage currents exter-nal to the cell such as:a) differential leakage currentswithin

the pack-protect circuit itself,b) differences in the insulation re-

sistance between cells, andc) humidity and condensation on

the pack-protect circuit boardand on the cell insulators.

4. Pack imbalance can be caused byintermodule or intramodule capac-ity differences due to:a) different lots of same cell,b) differences in module age, andc) cell electrolyte leakage, contami-

nation, or other damage.5. Replacement of battery modules

typically requires a system rebal-ance due to:a) the replacement module’s capac-

ity being different from othermodules or

b) the replacement module’s stateof charge being different fromother modules.

The resultant requirement is thata robust balancing capability mustbe designed into the whole batterysystem. In the instance where themodule design concept is utilized,this means intra- and intermodulebalancing.

FIGURE 4

High-energy battery system constructed from battery modules.


Example Implementationof Intra- and IntermoduleBalancing

Electronic cell balancing is notnew. Two common intramodule bal-ancing methods are discharge balanc-ing and charge transfer balancing.

Discharge balancing is balancingby discharging higher capacity cellsuntil they match the capacity of thelowest capacity cells.

Charge transfer balancing is balanc-ing cells by transferring charge fromthe higher capacity cells into the lowestcapacity cells until the cell capacitiesare equalized.

Both methods can theoretically bedone at any time and in any battery op-erating mode. Neither method will re-duce the usable capacity of a batterypack from what it was prior to beingbalanced.

These two intramodule balancingmethods are commonly only describedfor balancing across a complete, inflex-ible, battery system using centralizedcontrol. For highly configurablebattery systems constructed from inde-pendent, rechargeable battery modulesthere is an unmet need for an inter-module balancing method. The fol-lowing two methods, developed bySouthwest Electronic Energy Group,meet this need1.

Zener DiodeIntermodule Balancing

A simplified schematic of two,4-series Li-Ion battery modules thatutilize Zener Diode Intermodule Bal-ancing is shown in Figure 5. Assumed,but not shown, are the pack-protect cir-

cuits associated with each of the mod-ules. The two modules in the figure areunbalanced and are in the process ofbeing charged. The first module has at-tained full charge status and its chargeField Effect Transistor (FET) (shown as asimple switch) has opened. The othermodule is at a lower relative state ofcharge and has not yet attained fullcharge status. Charge current is by-passing the fully charged module via theZener diode and current limiting resistorand is charging the module at the lowerstate of charge. The charge current willcontinueuntil bothmodules are balanced

at which time the 2nd module’s pack-protect circuit will open its chargeFETs.

Figure 6 illustrates how ZenerDiode Intermodule Balancing works.Each module in the example has inter-nal charge control. Module 2 is at ahigher state of charge than Module 1.At the beginning of the data set, Mod-ule 2 is near its end-of-charge cycle andhas begun pulse charging—allowingcharge current to flow into bothmodulesin a pulsed fashion. When Module 2is at full charge, it stops pulsingand opens its charge FET. Module 1

FIGURE 5

Zener diode intermodule balancing circuit.

FIGURE 6

Zener diode intermodule balancing example.

1The methods in this article are protected by US pa-tents 7,609,031 B2; 7,279,867 B2; and other US andinternational patents already granted or pending.


completes its charge using the bypassZener diode current. When Module 1has reached full charge status, it alsoopens its charge FET. Both modulesare now balanced and charge currentstops going through the modules.Some small amount of quiescent currentwill bypass both modules as long asthe charging power source is attached.

Discharge Intra- andIntermodule Balancing

A simplified schematic of a four-series battery module that includesthe Li-Ion cells and the protect circuitis shown in Figure 7. The circuit in thefigure is capable of intramodule and in-termodule discharge balancing. Thecircuit is constructed using off-the-shelf parts including a microprocessor,an AD converter, an Analog Front Endcircuit, external balancing switches,and external discharge balancing resis-tors. An 8-Amp implementation of thepack-protect circuit in Figure 7 will fitonto a 2.5 × 0.75-inch printed circuitassembly.

As in the previous example, con-sider a battery system made from two,Figure 7 modules connected in series.Each Figure 7 module is able to bal-ance the cells it is connected to usingthe external FET switches and the25-Ω, 3/4-W discharge resistors. Thisis conventional intramodule balanc-ing. What may not be obvious is thateach Figure 7 module, under appropri-ate internal software control, is also ca-pable of intermodule balancing withthe other module connected in serieswith it without any control communi-cation between the modules.

Figure 8 illustrates how dischargeintermodule balancing using two, Fig-ure 7 modules connected in series, isaccomplished. The two modules are

programmed for intramodule chargecontrol to 80% capacity as might be re-quired in a battery back-up appli-cation. There are no control signalsconnecting these modules; the batterymodules’ external connections are onlyPACK+ and PACK−. A description ofthe action taking place in Figure 8follows.

Prior to being balanced, Module 2is at a higher state of charge thanModule 1—they are unbalanced. A34-V, current limited power supply isconnected across the two modules as acharge source. Module 1 has its chargeFETs constantly on but Module 2 isclose to being fully charged so it pulsesits charge FETs reducing average

FIGURE 7

Discharge intra- and intermodule balancing circuit.

FIGURE 8

Discharge module balancing example.


charge current. The pulsed charge cur-rent from Module 2 charges bothModule 2 and Module 1 until Mod-ule 2 reaches 81.5% capacity, opens itscharge FET, and stops pulse charging.Between charge pulses, Module 2 dis-charges itself down to 80% capacity byenabling all four of its balancing resis-tors. Module 1 does not discharge itselfduring this time because it has notreached 81.5% capacity. When Mod-ule 2 discharges down to 80% capacityit begins pulse charging once againuntil it again reaches 81.5% capacityand opens its charge FET. Thus,Mod-ule 2 charges and discharges itself be-tween 80% and 81.5% capacitywhile Module 1 only charges withoutdischarging. This continues untilModule 1 attains the same 81.5% ca-pacity at which time the two modulesbecome balanced. Once balance is at-tained, both modules continue to per-form 1.5% capacity charge—dischargemini-cycles. Pulse charge current rangeis approximately 2.2 to 3 Amps due to0.44-Ω resistor in series with the34-V charge source. Charging and dis-charging mini-cycles of 1.5% at about80% capacity is not stressful on thecells. Cycle rate is about 0.8 cyclesper hour, 19.2 cycles a day, and7,008 cycles a year. If end of life of acell is set at 80% of its full charge ca-pacity, an obvious question is howmany of these mini-cycles does it taketo cause the cells to reach end of life?Some NASA studies indicate thisnumber may be in the 10s to 100sof thousands. Thus, it is expectedthat continuous mini-cycles such asthis do not appreciably affect batterymodule life. Nevertheless, if mini-cycles are objectionable, it is possi-ble to lengthen them or to causethem to stop altogether once balanceis attained.

ConclusionsThe lithium-ion polymer version of

lithium-ion cells have been successfullytested for both charge and dischargeat pressures experienced in hadal zoneregions. Since the energy capacity oflithium-ion cells is two to four timesthat of conventional chemistry cells,operation at depth is significantly ex-tended when using these cells. TheLi-Ion chemistry does not outgas dur-ing charge or discharge and can there-fore be safely housed within sealedcontainers without the necessity of un-sealing and ventilating the containerduring charging. This feature allowsfaster, safer, andmore reliable redeploy-ment of lithium-ion powered marinesystems. It also allows the potential forcontinuous operation at depth when acharging umbilical is used.

Electronic balancing is a require-ment for large lithium-ion battery sys-tems because the chemistry does notprovide for overcharge balancing asdo previous rechargeable chemistries.Engineers, having to live with thisrestriction, are discovering that theability to automatically electronicallybalance all parts of a complex batterysystem leads to new paradigms in bat-tery systemdesign, use, andmaintenancethat are only recently becoming evi-dent. Among these are the following:1. use of battery modules to enhance

safety and reliability and to reducecosts;

2. applying electronic balancing toother non Li-Ion rechargeablechemistries;

3. increased number of series connec-tions in a battery;

4. increased flexibility in modularityand replaceable unit concepts;

5. smarter battery systems;6. more flexible charge control;7. multiple charger energy sources;

8. potential for multi-energy sourcehybridization; and

9. potential for construction of multi-voltage, multicapacity battery sys-tems each having intramodule andintermodule balancing capabilityand each constructed using thesame type of battery modules ineach system.


T E C H N I C A L N O T E

Pressure Testing: Best PracticesA U T H O R SKevin HardyDeepSea Power & Light

Matt JamesSouthwest Research

A B S T R A C TSuccess below the seas comes from careful preparation topside. Pressure test-

ing remains one of the most useful tools designers have available to assure theirsystems function as intended, whether a company chooses to have in-house pres-sure test capability or to work with a commercial test facility.

Capt. Don Walsh, pilot of the bathyscaph Trieste on its historic two-man dive tothe floor of the Challenger Deep in the Mariana Trench, said with a grin, “Successfuloperations depend upon a Skill-to-Luck ratio. While luck is important, you alwayswant skill to be more than 50%.”

Given the limited availability of ship time, the danger to personnel in close quar-ters onboard ship or in a submersible, the high cost of ship operations and equip-ment, and the long lead time of grant and project funding, pressure testing makessense to validate system integrity before deployment. Simply put, equipment shouldnot see pressure for the first time on its first operational deployment. Pressure test-ing is a vital environmental check of mechanical integrity, analogous to electronicsand software burn-in. Ideally, pressure testing will simulate the actual conditions ofdeployment and operation. A solid test provides the operator and deck crew confi-dence in the system being deployed.

While pressure testing will appear to add time and cost, in practice it saves bothby eliminating failure modes, some potentially catastrophic, while offshore.

This technical note is intended to summarize current best practices in pressuretesting for engineers and programs managers new to the field, including tips forcoordinating work with pressure test facilities. The lessons are based on theauthors' combined experience as users and operators of pressure test facilities.

Advantages

There are distinct advantages topressure testing. Pressure testing isthe best means to validate housing in-tegrity before expensive electronics areplaced inside, exposing hidden me-chanical flaws in extruded tubing orwelded seams or flaws in castings orforgings. Testing and developmentof pressure compensated systems canbe done faster at lower cost in thecontrolled conditions of the pressuretest laboratory, with far more accessto the system under study than inthe open ocean. Testing of any com-ponent exposed to pressure, even softrubber molded cable terminationsand urethane overmolds, is good prac-tice. Black rubber terminations havebeen known to have interior airvoids that show up only under pres-sure when the void collapses andwires short out. The bulk modulusof plastic may cause a part to shrinkto unacceptable dimensions and notfunction when needed most. Backon the surface, the part operates as ex-pected, and thoughts turn to deep seamythical creatures to explain the lackof data or recovered sample. In one case,a professor had a double o-ring seal on asliding piston. The small volume be-tween the o-rings caused the o-rings toseat and seize the piston. The trap didnot catch animals as expected. Carefulstudy and testing in a pressure chamber

revealed the problem. A pressure reliefport between the two seals in theopen position ended the problemand it worked fine thereafter.

While pressure testing can appearto be time consuming, and does addcost, in practice it saves time andadds confidence for a successful opera-tion by eliminating failure modes,some potentially catastrophic. Youwill get the best value by communicat-ing with the test facility as early as pos-sible. They have a lot of experience thatthey are delighted to share.

Pressure testing is useful at threekey junctures of development: (1)component validation, (2) system val-idation, and (3) proof testing.

Component validation qualifies apart or a subset of parts for integrationinto a system.

System validation tests the full as-sembly to the maximum defined staticpressure of the “design depth” andshould include cyclic testing to be certainthematerial can survive repeated deploy-ment. A test to “crush depth” confirmsfailuremode. If it is a new and critical ap-plication, or safety margins are beingtrimmed pretty close, it may be wise totest at least one article of the housingto implosion. This may be a costly testbut important information can begleaned by analyzing the failure modeand comparing calculated versus actualimplosion pressure and mode.


Proof testing is an in-process qualitycontrol test to “rated depth” after man-ufacture or overhaul.

Testing protocols may vary for thegeneral end user need: research, gov-ernment, military, or commercial.

Should a part fail in a chamber, it iseasy to pick up the pieces for forensicengineering. Feedthroughs allow datalogging and external power supplies.You can get in and out of a chamberfaster than you can access the deep sea,and for far less money. Pressure cham-bers are run by knowledgeable and expe-rienced technicianswho can often see theearly signs of leak or failure, and end thetest before things get out of hand.

LimitationsThere are limitations to pressure

chambers. While some chambers arelarge enough to fit the smaller workclass submersibles, like Deep Rover,there are times the ocean is the onlyplace large enough to pressure test afully assembled system. Jacques-YvesCousteau confirmed the integrity ofhis new two-man diving saucers bylowering them into the MediterraneanSea, unmanned, on a winch line with aweight below.

Tests of sympathetic implosion re-quire the “infinite volume” of the sea aspressure chambers rapidly loose pres-sure with the loss of any amount of vol-ume due to the largely incompressiblenature of water. The chamber wallsmay also artificially cause interactionswhich could dampen or amplify ashock wave.

Computer-AidedEngineering

Computer-aided engineering pro-grams, such as DeepSea Power &Light’s freeware “UnderPressure,” pro-

vide designers a first-order analysis ofsimple housing integrity against the af-fects of external pressure. Advancedusers will want to study the programfor opportunities to modify defaultmaterial properties to match theiractual material. Other simulationprograms, such as COMSOL 3.5(COMSOL, Inc., Burlington, MA)and SolidWorks COSMOS (Solid-Works Corporation, Concord, MA),provide motion, stress, or thermalmodels but are costly and not routinelyavailable to the average designer.

Common Typesof Pressure Vessels

Many pressure test vessels are inoperation today, and odds are there isone that has the size, pressure rating,and kind of feedthroughs you need(Figure 1).

Test vessel closures often incorpo-rate feedthroughs for power, signal,hydraulic power, or displacement.

Pressure ratings for pressure testvessels widely vary and are often de-pendent on size. Vessels with ratingsof 12,000 psi with a working diam-eter of 12 feet exist, but more com-mon chambers are 6 to 9 inches insidediameter.

Commercial enterprises may havechambers constructed to meet testingrequirements particular for theirneeds. Construction of test chamberscan be costly; in-house testing versuscontract testing must be consideredwhen deciding on new construction.

The most common type of high-pressure pumps is a piston pump.These are pneumatically driven, high-pressure liquid pumps, such as madeby Haskel Pumps (http://www.haskel.com). A large piston is powered bycompressed air, driving a small pistonthat alternately draws fluid into achamber through one check valve,then out through another checkvalve, providing a direct multi-plication of force in the ratio of thetwo piston areas. They are a simpledesign with few parts, easy to fieldstrip and repair, and reasonablyinexpensive. The action is reciprocal,and pressure is added in incrementalstep increases.

Other pumps include plungerpumps, hand pumps, and gear pumps.

The Test PlanCareful consideration should be

given to the test plan. Whether the testis a simple hydrostatic proof test, or acomplicated operational test with dataacquisition, adequate prior planning in-sures success. The goals of the particulartest as well as the capabilities of the testfacility should be given thought.

FIGURE 1

This new ASME-certified 20-inch chamber atDSPL can operate to 20 ksi and includes mul-tiple feedthrough ports. A 17-inch glasssphere from Vitrovex is shown being loweredinto the chamber for testing to a pressureequivalent to 8.4 km, the deepest trench inthe Atlantic Ocean.


Pressure testing should simulate theactual conditions of operation as well asthe extreme conditions expected in op-eration. Both deep and shallow depthsshould be considered in the test plan,and real-world situations need to bemodeled. For example, dwell time atthe surface before a dive may producea low-pressure leak that seals with in-creased pressure. This weakness maybe masked by a rapid transition tohigh pressure in a chamber.

The function of o-ring seals may bemarginal at lowpressure, but not at highpressure, under certain conditions. Tounderstand this requires some insightas to how o-rings function. There aretwo basic kinds of o-ring seals: staticand dynamic. A static seal is betweentwo parts that do not move; a dynamicseal has to accommodate some motionof parts, perhaps linear or rotary move-ment. Static seals, however, share somecharacteristics with dynamic seals inthat the o-ring itself moves, slidinginto sealing position in compliancewith increasing pressure. Thus, theremaybe low-pressure conditions wherethe movement of the o-ring is compro-mised, perhaps because of use of a highdurometer rubber, improper surfacefinish, or even too much grease. Alow-pressure test, even a soak test in atub of water, can reveal this problem.A rush to push the test sample to highpressuremay cause the engineer to over-look this potential seal failure mode.

An autonomous undersea vehicle or awire lowered conductivity-temperature-depth instrument package will see cy-clic pressure stresses. Plastics may creepor compress under long-term exposureto high pressure.

Testing Best PracticesWhen working with a testing

house, it is important to define the

test plan in writing. The act of writingwill help clarify your thinking. Theplan should be offered to the testingfacility with enough time for themto carefully review and comment onthe testing. They have lots of experi-ence, which can be quite helpful. In-clude the proposed test dates toensure your desired window fits withintheir availability.

The test plan should consider thefollowing, if relevant:1. Purpose: Define what constitutes

“pass/fail.” That may simply be “Isit dry inside?” The question may bedefined by whether the test is forcomponent validation, system vali-dation, or proof testing as definedabove.

2. Standards and certifications: If thetesting is to meet specific standards,such as American Bureau of Ship-ping, Underwriters Laboratories,or U.S. Government Specification(MilSpec), be sure to inform thetest facility of what they may needto provide in terms of gauge cali-brations or other data. It will beyou that is responsible for definingthe test protocols and submittingthe results to the certifying agency.

3. Safety factor: Discuss with the pres-sure facility what are the design lim-its, including safety factor, and howthey were determined.

4. Use blocking. If this is the first timean empty housing is being taken tothe design depth, the interior im-plodable volume should be filled to90% or better with an incompress-ible material to limit the amount ofenergy released by a catastrophic im-plosion. A 98% fill may be requiredif the system is being taken in-tentionally to failure. If practical, awater-filled interior vented throughthe end cap to atmospheric pressureis a good choice. Another good prac-

tice is the use of polypropylene plas-tic injection molding pellets whichfloat if spilled, making them easy toclean up. These are also good energyabsorbers if an implosion occurs.

5. Measurement techniques: The testmay look to simply confirm that noseals leak. Other tests may measurevolumetric displacement, straingauge deflection, voltages, systemfunction, video, or count pressurecycles. Define what test equipmentwill be needed and where it willcome from. Consider asking thetest facility what equipment theymight have or to suggest wherethey might rent it.

6. Calibrations: Pressure facilities typ-ically have a yearly schedule for re-calibrating their gauges, meters,and other measurement devices.

7. Environmental simulation: Definerate of pressurization and depres-surization, number of cycles, holdtimes at pressure and at sea level,water temperature, fresh or saltwater,and maximum test pressure. Not alltest facilities can offer this great anarray of options, but some do.

8. Electrical interface: Specify thevoltage and current requirementsfor any power-on testing, as maybe required. Specify the requiredconnectors and cables your projectuses. Ask the test facility if theyhave an adapter for the thread sizeof your bulkhead. If one has to befabricated, it is better to know soonerthan later. This may incur additionalcosts and preparation time. Send theadapter to checkfit. It is your respon-sibility to bring the connectors anddummies you need.

9. Pressure compensation systems: Ifthere is oil, specify how will it bemanaged during fill, and if anyleaks or spills. Provide the Ma-terial Safety Data Sheet to the test


facility. If the compensation sys-tem is compressed air, specify theventing plan intended duringdepressurization.

10. Hazards: If the housing fails andwater gets inside, specify if therematerials, like primary lithiumbatteries, that will react vigorouslywith water. If a seal fails, and theinterior becomes positively pres-surized, specify if there a way torelieve the interior pressure safely,such as a PRV.

11. Specify howmany tests are neededfor the statistical sample size.

12. SchedulingA. Schedule with the facility as

early as possible so they knowto have the gauges you want,and not be out for recalibration.

B. Communicate well in advancewith the pressure test facility,giving them a detailed plan aminimum of 2 weeks beforeyou show up. They cannotquote costs unless they knowwhat you want to do and whatyou expect from them.

C. Ship ahead. UPS is great, butallow a day or two extra soyou do not sweat it.

D. Allow adequate time for setupand breakdown.

13. Come prepared. If you need feed-throughs, or an extra tech, let themknow what to plan for. Make cer-tain you have everything you needbefore you ship your gear. Do adry-run setup and think it through.Checklists are always helpful. Talkwith your colleagues to be sure youhave all the right connectors, cables,test equipment, and gizmos youwill require.

Use of this checklist will help yoube ready when the clock starts running(Figure 2).

Rules of Thumb

1. Provide a well-written plan, includ-ing materials and checklists. If youare not going to be present, reviewthe plan with the pressure test facil-ity before the test day to prevent aneedless delay while the operatortries to contact you to determine ex-actly what was intended. Considerlow-pressure and low-temperaturecases as well and high pressure.

2. Allow time for setup and break-down, easily a half day on eachend, depending on system and testcomplexity. If you need more timethan this, let the pressure facilityknow and they will be able to setyou up with appropriate work space.

3. Leaks or implosion may happen,that is why we pressure test things.Have a plan to cope with the loss. Ifexpensive components do not needto be inside the housing for the ini-tial test, save yourself the grief. Con-sider the possibility that the interiorof a pressure case that leaked mayhold high interior pressure whenhandling. Perhaps you can releasepressure by loosening connectors.

4. Handling:A. If there is something that should

not be touched, like a sensor, orneeds extra attention, like a plasticconnector, let the operator know.They really do appreciate youspeaking up. It is really desirablefor the owner of the equipmentto be present to operate theirdata logging equipment or simplyobserve the test. Simple pressuretesting may be dropped off andpicked up later, but the basic pro-tocol of going through the bestpractices noted above with theoperator should never be shortcut.

B. Wet things can be slippery. Usegloves that maximize gr ipstrength. Pay attention whenand where you grab something.The use of pressure facilities is atyour own risk. Operators do notassume any liability for damage toyou or your equipment.

C. Facilitymanagers do not generallyallow clients to load and unloadchambers or operate the pressuresystem controls. However, mostopenly welcome your participa-tion on site in giving detailed di-rection to testing your system.You are welcome to discuss train-ing and experience of the pressuresystem operators.

5. Agree on payment terms before com-ing to the facility. Review any liabilitywaivers for clarity. Understand thatmost quotes for pressure testing areestimates based on the test plan pro-vided. Delays are inevitable as proce-dures get more complex.

Future FundingFederal agencies that provide block

funding for ship days to research orga-

FIGURE 2

Southwest Research Institute prepares a sub-mersible for hydrostatic test. Southwest Re-search Institute operates ocean simulationchambers with diameters up to 90 inchesand pressures to 30,000 lb per square inch.


nizations would do well to also con-sider pressure testing block funding.Researchers will have greater successat sea and stretch research dollars bytesting their equipment before they go.

ConclusionPressure testing is a critical part of

preparation and a key to success atsea. It is a critical environmental testthat should always be part of routinedesign and manufacturing plans. Pres-sure testing provides the operator, deckcrew, and submersible crew confidencein the system being deployed.

AcknowledgmentsThe authors gratefully recognize les-

sons learned from the U.S. Navy ArcticSubmarine Laboratory (Point Loma,CA) and from the Scripps Institution ofOceanography’s Hydraulics Laboratory(La Jolla, CA). Thanks to Peter Weber,Kymar Subsea, and Steve Weston andJohn Sanderson, DeepSea Power &Light, for their review and valuablecontributions to this article. Thanksto Jesse Ramon, SwRI, and Lee Reis,SwRI, for their valuable knowledgeand continued dedication to subseatest and evaluation.


P A P E R

Microbial Life in the TrenchesA U T H O RDouglas H. BartlettScripps Institution of Oceanography

A B S T R A C TMicrobiologists have been making use of advances in ocean engineering to ex-

plore life in deep-sea trenches for decades, including for many years precedingman’s conquest of the Challenger Deep. This has fostered the development of anunusual branch of microbiology, referred to as high-pressure microbiology. Evi-dence for deep-trench microbes that grow best at elevated hydrostatic pressurewas first obtained in the early 1950s, and isolates were obtained in pure culturesbeginning in the early 1980s. Here I describe some of the history of deep-trenchmicrobiology and the characteristics of microbial life in the trenches.Keywords: Barophile, Challenger Deep, High pressure, Piezophile, Trench

Introduction

I n this article, I focus on the small-est inhabitants of trench ecosystems—the microorganisms, those tiny lifeforms less than one millionth of aninch in length. It is they that accountfor most of the evolution that has oc-curred, it is they that represent thelargest numbers of cells and combinedbiomass on the planet, it is they thatprovide us with the bulk of our biolog-ically derived pharmaceuticals and bio-technology products, and it is they thatdrive the biogeochemical cycles thatsustain our biosphere on spaceshipEarth. During the past half centuryof science, we have learned moreabout both hadal environments andmicrobes than in all the precedingtime periods. Here I discuss the inter-section of these fields.

The opportunity to engage in thescience of deep-sea microbiology hasrelied on those advances in ocean engi-neering of which regularMarine Tech-nology Society Journal readers will bewell aware. Restricting these consid-erations only to the Challenger Deepstill offers many examples of the toolsof the trade. Challenger Deep descentshave been accomplished sporadicallysince the middle of the 20th century.Some of these are well known, likethe dramatic undertaking of themanned bathyscaph Trieste, andsome, such as the benthic sampling op-erations of the former Soviet Union inthis and other trench environments,

have received much less internationalfanfare. These deployments have useddeep trawls and bottom-grab sedimentsamplers, free-falling/ascending vehi-cles, deep conductivity, temperature,depth sensor (CTD) casts, deep cur-rent meter moorings, the remotely op-erated vehicles Kaiko and Kaiko7000,and most recently the hybrid remotelyoperated vehicle Nereus. Similar opera-tions have taken place in many othertrenches, most notably the Aleutian,Kermadec, Tonga, Philippine, Japan,and Kuril-Kamchatka trenches in thePacific Ocean, the Java Trench in theIndian Ocean, and the Puerto RicoTrench in the Atlantic Ocean. Readersinterested in a virtual trip to any ofthese locations should downloadGoogle Earth.

Danish and SovietContributions

An examination of the history ofdeep-trench microbiology provideslessons beyond the science itself tothe noble and the brutish that is possi-ble in human society. Voyages of dis-covery often require sacrifice. Thiswas certainly true for the Danish re-

search expedition that took place dur-ing the early 1950s, conducted onboard the Royal Danish Navy shipGalathea. A focus of this research en-terprise was to determine the deepestplaces where life existed. It is a tributeto the people of Denmark that thisgreat undertaking took place at all.The great deep-sea microbiologist,Claude ZoBell, recorded in his mem-oirs that “having been impoverishedduring World War II and its sequelae,the people of Denmark had little tocontribute except an active interest inthe expedition. School children wereorganized to contribute or collectfunds and to sell bananas, coffee, pine-apples, and other coveted commoditiesat black-market prices with official per-mission. American cigarettes alonenetted more then 8 million kroner(about $75,000) for the ExpeditionFund.”

Even greater sacrifice was requiredby certain Soviet scientists of thisperiod (Mishustina, 2003). AnatoliiEvseevich Kriss, a contemporary ofZoBell and another creative forcein marine microbiology, suffered as aresult of political persecution. Krisstook over the leadership of the Depart-


ment of Marine Microbiology at theInstitute of Microbiology (USSRAcademy of Sciences) in 1950. Hemade the astounding claim that inthe depths of the Black Sea, dark fixa-tion of carbon dioxide exceeded thelevels of photosynthesis by plants insurface waters. This claim was decadesahead of the experimental work thatwould one day be corroborated. Itwas also apparently too far ahead forSoviet scientific thinking. He was per-manently criticized for his statementsabout chemosynthesis. Things weremuch worse for G. A. Nadson, Kriss’teacher and founder of the institutewho was arrested and later executed.Kriss survived these ordeals and wenton to explore the bacteria and fungi ofmany marine, including deep-trenchenvironments, and wrote a textbookon marine microbiology, which waswidely read owing to its Englishtranslation.

Claude E. ZoBellThe aforementioned Royal Danish

Navy ship Galathea “Round theWorld” made possible a tremendousamount of deep-sea science, and inparticular the expedition affordedZoBell with the opportunity to exam-ine the microbiology of many exoticdeep-sea sediment samples (ZoBell,1952). He made good use of thismaterial, using it to obtain the first ev-idence of deep-ocean trench high-pressure adapted life.

This discovery highlights the un-usual nature of doing microbiology athigh pressure. It was accomplished byusing as inocula mud that had beencollected from trenches exceeding10,000 meters and incubating at pres-sures of 100 MPa (1,000 atmospheresor ∼15,000 pounds per square inch)and temperatures near freezing. To

do this was no small feat. Once thesediments were hauled on board,ZoBell and his student had to quicklytransfer some of thismaterial into bottleswith culture media, stopper them, andplace these inocula into pressurizablesteel cylinders. This type of microbiol-ogy is a very odd business and is basicallyunchanged in its operation today, in-volving just as much ability in plumb-ing and chemical engineering as steriletechnique and microbial physiol-ogy. The culture apparatus of a deep-sea microbiologist requires that the“soup” containing the microbes to begrown be placed into some sort of apressure-transmitting container. Itcan be a bag that is squeezable, a sealedsyringe (the movement of the plungerrelays the pressure to the cells), or aglass tube with a movable stopper.These containers are then placed insidea pressure vessel of some design andpumped full of water to the desiredpressure. Water (hydrostatic) pressureis generally used and not gas pressurebecause gases can be toxic to microbesand pose an explosion risk to scientists(Figure 1).

A. Aristides Yayanos

Although ZoBell was successful atfinding evidence of piezophilic (for-merly barophil ic; high-pressureadapted) life, he failed to isolate anypiezophilic microbes or indeed tomaintain any cultures of consortia ofpiezophilic bacteria that could bemade available for others to examine.This breakthrough was accomplishedby another microbial oceanographeralso at Scripps Institution of Oceanog-raphy, A. Aristides Yayanos (Yayanoset al., 1982). It required about threemore decades, during which time thevery existence of piezophiles was anissue of active debate. However, in1979, Art Yayanos, through greatcare, patience, and dedication, isolatedthe first piezophilic bacterial strain.Shortly thereafter, in 1981, he ob-tained a piezophilic microbial speciesfrom the Mariana Trench that couldnot grow at atmospheric pressure andhencewas referred to as being obligatelypiezophilic. Yayanos went on to iso-late hundreds of new strains fromthe Aleutian, Kermadec, Mariana,Philippine, and Tonga trenches as wellas other deep-sea locations. These con-tinue to be the gifts that keep on giv-ing as other scientists can now “godeep” so to speak by simply crackingopen a pressure vessel containing oneof Yayanos’ strains (Figure 2).

Part of the reason for Yayanos’ suc-cess may have been his choice of start-ing material. Many of his piezophilescan be traced back to the decaying re-mains of an amphipod. These benthiccrustaceans have two advantages forthe isolation of piezophilic microbes:(1) they harbor large numbers of bac-teria on and in them, and (2) each spe-cies is restricted to a narrow physicalrange, and thus deep-trench amphi-pods must contain a microbial flora

FIGURE 1

The odd business of high-pressure microbiol-ogy. Shown is the great deep-sea microbiolo-gist Claude E. ZoBell with his vessels andhand-operated high-pressure pump. Courtesyof Scripps archives.


that is adapted to high-pressure deep-trench conditions.

Program DEEPSTARSince the initial isolations of piezo-

philes, others have gone on to obtainand to characterize additional trenchmicrobes. Particularly spectacularhave been the activities of the JapanAgency for Marine-Earth Science andTechnology (JAMSTEC), beginningin 1990 with the establishment of theDEEPSTAR program. This organi-zation has placed great emphasis onthe science of the inner space of theoceans, particularly within the Japan,Ryuku, and Mariana trenches.

Advances in ocean engineeringhave preceded many of the JAMSTECaccomplishments in deep-sea microbi-ology. These have included the devel-opment of a series of submersibles andremote-operated vehicles. Another en-gineering marvel is the JAMSTECDEEPBATH system. Although envi-ronmental microbiologists have comeup with ingenious approaches for cul-tivating deep-sea microbes at highpressure, the most sophisticated sys-tem ever developed is undoubtedlyDEEPBATH. This system is used in

conjunctions with specialized pressure-retaining mud samplers that can beused by either manned submersibleor remote-operated vehicle. Once ob-tained, the samples are kept at deep-sea pressures and temperatures untilprocessing time. After delivery of thisun-decompressed material to theDEEPBATH system, it is dilutedunder in situ pressure conditions anddelivered to an isolation devise for ex-tinction to dilution isolation of singlemicrobial species and laser-based auto-mated monitoring of growth. Thenthe individual isolates are pumpedinto a flow-through cultivation vesselwhere they are grown up in sufficientquantities for biochemical or molec-ular biological studies. The entireDEEPBATH operation is monitoredand controlled by a single console.

JAMSTEC microbiologists haveused DEEPBATH to isolate and taxo-nomically characterize a large variety ofdeep-trench microbes that grow underdiverse physical and chemical condi-tions (Kato et al., 1998) (Figure 3).

Microbial InvadersOne of the curious features of

many of the microbes that have beenisolated from deep-sea settings includ-ing trenches is that they do not displayadaptations for growth at either thehigh pressure or the low temperature

from whence they were isolated. Thisseems counterintuitive, after all howcould life exist at depth that cannotgrow under the conditions present atdepth? The answer to this riddle mayrest on the fact that deep-ocean habi-tats are physically connected to theiroverlying surface waters, and a varietyof physical and biological processesexist, which can deliver microbesfrom land, air, and shallow sea todeep-oceanic pelagic and benthic en-vironments. Thus, the nonpiezophilicorganisms present in trenches may rep-resent those immigrants that have sur-vived the lengthy transit from muchshallower locations. Although the con-ditions at depth are extreme, the pre-vailing physical conditions may havethe effect of putting some cells into astate of suspended animation, and theturnover of such nongrowingmicrobesmay be very low. This may be particu-larly true for spores, those dormantstages of some bacterial groups. A re-flection of this phenomenon is thathigh numbers of sewage microbesmay remain viable for years at deep-ocean dump sites, something policy-makers should be aware of whenconsidering deep-ocean locations forwaste disposal.

Deep-Trench MicrobesLove the Big Squeeze andDo Not Get the Bends

There are two common miscon-ceptions about deep-sea piezophilicmicrobes. First they do not generallyblow up (get the bends) during decom-pression. At least this is true for most ofthe microbes present in culture, in-cluding those obtained without de-compression. The reason is becausethey do not typically have gas spacesinside their cells, and so there is no

FIGURE 3

The remote-operated vehicle Kaiko collect-ing mud in the Challenger Deep. Courtesyof Dr. Chiaki Kato, JAMSTEC.

FIGURE 2

Themost important discovery evermade in theMariana Trench. Shown is an electron micro-graph of the high-pressure requiring micro-organism strain MT41, isolated by A. AristidesYayanos and colleagues. The scale bar is equalto 0.5 μm. Courtesy of ASM Press. (Chastainand Yayanos, 1991).


gas expansion during decompression.The most piezophilic microbe everobtained, Yayanos’ first obligate piezo-phile isolated from the MarianaTrench, was obtained with decom-pression during capture and deliveryto surface waters. It does lyse afterdecompression; however, viabilityonly goes down about 2-fold after10 h and about 20-fold after 30 h at at-mospheric pressure. Some cells are notso lucky. The hydrothermal vent mi-crobe Methanocaldococcus jannaschii,which lives off of dissolved gases ofhydrogen and carbon dioxide, un-dergoes extensive cell rupture underthe specialized conditions of rapiddecompression.

The second misconception is thatpiezophiles must have a super thickand tough cell wall, like the hull of asubmarine, to withstand all that pres-sure. The pressure inside a piezophileis pretty much the same as that outsidethe cell. Their adaptations are not a re-flection of mechanical engineering butrather of biochemical adaptation. Theavailability of piezophilic microbes inculture collections at places likeScripps and JAMSTEC has made itpossible to address the biochemicalandmolecular bases of life at high pres-sure (Michiels et al., 2008). Deep-seaorganisms have many biochemicaladaptations for life in the big squeeze.Most seem to possess high levels ofomega-3 polyunsaturated fatty acidsin their membranes, the sort of“heart-healthy” molecules that manyof us consume daily in the form offish oil pills. These function to keepmembranes of deep-sea life from freez-ing up. Other adaptations enable themto make DNA and protein and to bemotile and undergo cell division athigh pressure. It is likely that manyproteins from piezophiles have evolvedstructural changes that maintain their

ability to interact with other proteinsor with substrates required to carryout enzymatic function. Also, becausenutrients tend to be scarce in the deepsea, the microbes there have evolvedabilities to take up and metabolize agreat range of food sources, many ofwhich cannot be used by surface-dwelling bacteria.

In addition to possessing adapta-tions to the dark ocean, piezophileslack adaptations necessary to exist inlighted surface world. They lack en-zymes referred to as photolyases thatare used to repair DNA damaged byexposure to ultraviolet light. We havefound that the addition of a singleshallow-water photolyase gene to adeep-sea microbe may render it10,000× more resistant to ultravioletrays (Bartlett and Lauro; unpublishedresults).

Thank You, Piccardand Walsh

Much of our current knowledge ofthe operation of piezophiles has beenmade possible by advances over thepast decade in genetics and genomics.This has resulted in the identificationof genes important for high-pressuresensing, the control of gene expressionand growth. It is now possible to gofrom the isolation of a deep-trench mi-crobe to the elucidation of its blueprintgenome sequence in less than 1 year.Biophysicists now ponder the role ofspecific membrane-spanning regionsin a hydrostatic pressure-sensing pro-tein that can relay information neededto turn on or to turn off a gene. It isunlikely that this level of detailed anal-ysis was ever contemplated by JacquesPiccard and Donald Walsh or evenClaude ZoBell and Anatolii EvseevichKriss. However, it all traces back totheir legacies.

Lead Author:Douglas H. BartlettMarine Biology Research Division,Center for Marine Biotechnologyand BiomedicineScripps Institution of OceanographyUniversity of California, San DiegoLa Jolla, CA 92093-0202Email: [email protected].: 858-534-5233;Fax: 858-534-7313

ReferencesChastain, R., Yayanos, A. A. 1991. Ultra-

structural changes in an obligately barophilic

marine bacterium after decompression. Appl.

Environ. Microbiol. 57(5):1489-1497.

Kato, C., Li, L., Nogi, Y., Nakamura, Y.,

Tamaoka, J., Horikoshi, K. 1998. Extremely

barophilic bacteria isolated from the Mariana

Trench, Challenger Deep, at a depth of

11,000 meters. Appl. Environ. Microbiol.

64(4):1510-1513.

Michiels, C., Bartlett, D. H., Aertsen, A.,

eds. 2008. High-pressure microbiology.

Washington DC: ASM Press.

Mishustina, I. E. 2003. History of marine

microbiology in Russia (the Soviet Union) in

the second half of the 20th century. Biol. Bull.

30(5):525-529.

Yayanos, A. A., Dietz, A. S., Van Boxtel, R.

1982. Obligately barophilic bacterium from

the Mariana trench. Proc. Natl. Acad. Sci.

U. S. A. 78(8):5212-5215.

ZoBell, C. E. 1952. Bacterial life at the bot-

tom of the Philippine Trench. Science.

115(2993):507-508.


T E C H N I C A L N O T E

Recovery of Live Amphipods at Over102 MPa from the Challenger DeepA U T H O RA. Aristides YayanosScripps Institution of Oceanography,University of California at San Diego

Introduction

I n the early 1970s I began a pro-gram to bring live animals from theMarianas Trench into the laboratory.In one sense, this is the inverse of whatPiccard and Walsh accomplished intheir historic and heroic dive in theBathyscaph Trieste (Piccard andDietz, 1961). That is, just as Walshand Piccard were protected from theknown lethal effects of compressionto view animal inhabitants in the Chal-lenger Deep, these inhabitants wouldneed to be protected from the pre-sumed lethal effects of decompressionto be viewed in our environment.

The essential tasks were first toidentify a trench inhabitant and thento devise a method for catching it.Deep-sea photography provided theclue. E. Newton Harvey may havebeen the first to use an attractant tobring organisms into the field ofview of a deep-sea camera (Harvey,1939). He used a wooden model ofa fish painted with spots of lumines-cent paint and failed to photographany animals. Since he was the leadingpioneer in the study of biolumines-cence, it seems natural for him tohave employed luminescence as an at-tractant. The photographic investi-gation of deep-sea life with the use ofattractants of any kind was apparentlynot resumed in earnest by anyone

until the 1960s with the work ofIsaacs and his colleagues at ScrippsInstitution of Oceanography (Baileyet al., 2007). Their work with baitand cameras (so-called baited cam-eras) yielded pictures showing thepresence of large, mobile mega-faunain the abyssal and hadal ocean (Isaacs,1969; Isaacs and Schwartzlose, 1975).This research brought about a signifi-cant change in our view of deep sea

ecology (Dayton and Hessler, 1972;Haedrich and Rowe, 1977).

In 1972, deep-sea photographsshowed not only that amphipodswere attracted to bait but also thatthey would swim into containerswhere bait had been placed (Hessleret al., 1972). This made them primesubjects for live capture for physiolog-ical studies. The proliferation of baitedcamera and baited trap deploymentsinto the deep sea that began in the1970s led to the conclusion that am-phipods, usually less than 10 cm in

length, are perhaps ubiquitous in thedeep sea, including trenches (Hessleret al., 1978; Yayanos and Nevenzel,1978). Not only are these amphipodsubiquitous but also thousands of themare often caught in a single small trap.This is not surprising based on thenumber of them seen in baited cameraphotographs.

Figure 1 shows a sequence of pic-tures taken for me by Simon Ferreira of

the Isaacs research group on INDOPACExpedition in 1977 in the MarianasTrench at a depth of 10,599 m(11° 21.3′ N 142° 13.8′ E) close toif not in the Trieste Deep (11° 18.5′ N142° 15.5′ E). The number of amphi-pods increases for several hours in thefield of view of the camera in succes-sive photographs taken 5 min apart.Figure 2 is a shipboard photographof an individual amphipod retrievedin a basket trap from the ChallengerDeep of the Marianas Trench. Figure 3is a graph showing the number of

FIGURE 1

Four of 365 time lapse pictures taken at a depth of 10,599 m close to 11° 21.3′ N 142° 13.8′ E in1977. If we assume, frame A was taken at 5 min, B was at 45min, C at 950min, and D at 1,500 min.Almost all of the animals in the 365 photographs were amphipods.


these amphipods approaching baitover time. Parenthetically, fish werenot observed in this sequence of over365 photographs. Failure to observefish does not imply their absence asinhabitants or transient visitors in theChallenger Deep because not enoughis known regarding issues such as suc-cession of scavengers at bait falls, scav-enger food preferences, whether fishfrom shallower depths are only oc-casional visitors and other factors(Jamieson et al., 2009).

In summary, photographic obser-vations and trapping results clearlyshowed that amphipods are excellent

target organisms for retrieval in pres-surized traps. Furthermore, mostamphipods are small enough to becaught in a trap of manageable size,an important consideration for a pres-sure vessel trap.

MethodsFigure 4 shows a pressure-vessel I

designed and had fabricated in 1973for the purpose of trapping and recov-ering live amphipods at high pressurefrom any ocean depth (Yayanos, 1977).The blocks of titanium (the 6Al4Valloy) from which the traps were fab-ricated were acquired at no cost fromU.S. surplus government property.Curiously, I designed the trap basedon the size and shape of this block,as apposed to designing the trap andthen acquiring the block. One essen-

tial feature of the trap is the slidingpiston closure (Figure 4) that allowsclosing the pressure vessel on the bot-tom of the sea with a sliding motion.Macdonald and Gilchrist (1969) alsoused a sliding closure, namely, a ballvalve, in devices that retrieved waterunder pressure to depths of 2,000 mand live amphipods from a depth of2,700 m (Macdonald, 1978). Theyfurther showed that a gas-containingaccumulator was essential for a pressure-vessel sampler to maintain its contentsclose to the pressure at which it closed.An accumulator minimizes the pres-sure drop inside a pressure-vessel trapas the external pressure falls during as-cent from the sea floor causing (1) theseals in the trap move and (2) the trapitself to expand because of metal com-pressibility. An accumulator of ap-propriate size and filled with nitrogengas minimizes these two effects. Forexample, a pressure drop of 20 MPacan be reduced to 2 MPa with anaccumulator.

Figure 4 shows a pressure equil-ibration hole drilled into the pressure-retaining animal trap (PRAT) body.With the trap in an open position,the O-rings on the piston straddlethis hole. Without the hole, the thincylindrical space bounded by theO-rings, the piston wall, and the cyl-inder wall becomes a sealed space atatmospheric pressure at the begin-ning of a deployment. As the externalpressure increases during descent tothe sea floor, the O-rings move towardeach other and the piston cannot bemoved at depth. I established theneed for this equilibration hole byusing a pressure testing facility at theArctic Submarine Lab in San Diego.The pressure equilibration hole keepsthe pressure on both sides of theO-rings the same and allows the pistonto move freely at any depth.

FIGURE 4

This sketch of a PRAT is modified from onepreviously published (Yayanos, 1977). Whendeployed to the sea floor, the top of the pis-ton is below the trap cavity, allowing animalsto enter. The piston slides to seal the cavityalong with any animals in it. As the trap risesfrom the sea floor, the O-rings on the pistonare pushed equally in opposite directionsuntil a seal is formed. Along with an attachedaccumulator, the pressure in the trap cavityremains close to value on the sea floor.

FIGURE 3

The graph shows the number of amphipodssurrounding bait on the sea floor of the Chal-lenger Deep as a function of time after thearrival of bait. The amphipods were countedin a consistently chosen field of view of thecamera in photos such as those in Figure 2.

FIGURE 2

This picture of a specimen (approximately4.5 cm long) of Hirondellea gigas was takenat atmospheric pressure on board ship. Sofar, traps set in the Marianas Trench haverecovered this species exclusively.


Figure 5 shows the first ocean de-ployment of a PRAT over the AleutianTrench in 1974. The overall design ofthe free vehicle in Figure 5 is based onthe designs of others at Scripps Institu-tion of Oceanography (Shutts, 1975).Our free vehicles with their 450 litersof Isopar-M® for buoyancy (Figure 5)are decidedly easier to use on shipswith low freeboard.

Results and DiscussionThe first trial over the Aleutian

Trench failed because of the lack of apressure equilibration hole (Figure 4)and the equipment was almost lostbecause the ballast release timer(Figure 5) did not work. In 1975, werecovered amphipods under pres-sure, but not alive, from the PhilippineTrench. The timed ballast releasemechanism shown in Figure 5 againdid not function properly causing areliance on magnesium releases. This

in turn resulted in unpredictable sur-facing of the free vehicles, in a delayof recovering them, and in the temper-ature of PRATs equilibrating with thatof warm surface waters. In 1977, webegan to use highly reliable timed re-leases (Sessions and Marshall, 1971)and to insulate the PRATs. By 1981,we were using insulation fabricatedfrom 2-inch-thick sheets of Lexan®

(Figure 6). In 1977, we successfully re-covered live animals at 58 MPa froman abyssal depth of 5,800 m (Yayanos,1978).

Not until RAMA Expedition Leg7, to the Philippine Trench and theMarianas Trench, were we successfulin retrieving live animals from hadaldepths. On November 21, 1980, werecovered a PRAT containing live ani-mals at 102.6 MPa. The PRAT hadbeen deployed at 11° 18.7′ N 142°11.6′ E over the Marianas Trench to

a depth of approximately 10,900 m.Observations of amphipods throughthe windows in PRATs (see Fig-ure 7), although rudimentary, pro-vide new information of the potentialof amphipods to migrate vertically(Yayanos, 1981) and of their statusduring confinement in a trap. Amphi-pods have appendages called pleopodsthat serve essential functions such aslocomotion and respiration (Boudrias,2002). Table 1 shows the pleopod beat

FIGURE 5

Panel a, on the left, is from a previous publication (Yayanos, 1980) and shows how a PRATappears during deployment and on the sea floor. The minnow bucket contains bait (panel b onthe right) to attract amphipods and some of these usually enter the trap chamber. The mast andfloats attach to a cable on the body of a PRAT. The expendable ballast, not shown, attaches tothe timed ballast release mechanism via a magnesium back-up release. The tension caused(1) by the weight of the ballast pulling the piston out of the body of the PRAT until it restson the piston stop and (2) by the buoyant force of the floats keeps the trap entrance open.Two springs (one visible in panel b) move the piston to the closed position when this tensiondisappears due to release of ballast. The floats are linear polyethylene jugs filled with Isopar-M®

(Shutts, 1975; Yayanos, 1976).

FIGURE 6

PRATs deployed in the Marianas Trench were inrectangular cases to provide insulation of trappedanimals from the warm temperatures of the sur-face waters. The walls and cover (not shown) ofeach insulation case were made from Lexan®,2-inches thick. The accumulator attached to thepiston side of the PRAT is visible in this photo.

FIGURE 7

Photograph shows a live swimming abyssalamphipod near one of the windows of aPRAT at 58 MPa.


frequencies observed in any of five an-imals randomly selected over severaldays of confinement in the PRAT at102.6 MPa and 2.8°C. The tempera-ture at the bottom of the MarianasTrench is 2.46°C (Mantyla and Reid,1978), very close to that measured inthe Philippine Trench (Bruun andKillerich, 1955). We kept the animalsalive for 5 days by periodically circulat-ing filtered seawater through the trapwith a high pressure seawater circulat-ing system.

Experiments conducted with am-phipods from theMarianas and Philip-pine Trenches show that these animalsmay be capable of a substantial verti-cal migration to depths as shallow as3,800 m. Their tolerance for decom-pression seems greater than that ofamphipods living at 5,800 m. The du-ration of tolerance to shallower depths,however, remains to be determined.In the few experiments conducted,decompression completely to atmo-spheric pressure was lethal, with thenoted absence of activity following re-compression. It remains a possibilitythat if we had employed a different re-compression regime, then the amphi-pods would have recovered. Recentstudies of Tonga Trench amphipodssuggest that their ability to live at shal-lower depths is important in their re-productive biology (Blankenshipet al., 2006). The vertical migrationof Tonga Trench amphipods is wellwithin the limits surmised from ex-periments with Marianas Trench andPhilippine Trench amphipods.

AcknowledgmentsI am indebted either for inspiration

through their work or direct assistanceto many people, among whom areR.H. Hessler, A.G. Macdonald, J.D.

TABLE 1

Pleopod beats per minute at 103 MPa for randomly observed amphipods (5) in PRAT 6. Theamphipods were sealed in the PRAT on the sea floor at 06:30 on November 21, 1980.

Date Time Beats/min

November 21, 1980 06:30

15:36 40.5

20:45 52.5

21:50 61.1

22:40 94.7

23:00 55.6

23:05 100.0

November 22, 1980 18:10 121.6

140.0

65.9

73.0

57.6

69.2

133.3

November 23, 1980 70.2

80.0

7:00 81.1

20:50 70.1

140.0

November 24, 1980 137.6

76.4

83.3

November 25, 1980 14:35 87.0

16:05 77.3

16:07 77.4

20:36 69.4

November 26, 1980 9:15 79.1

16:55 84.5

120.0

68.2

67.9

67.6

November 27, 1980 15:50 120.0

51.1

104.3


Isaacs, R.L. Fisher, M.H. Sessions, M.Monahan, W. Schneider, R. Van Box-tel, R. Wilson, and Captain C. John-son of R /V Thomas Washingtonduring Leg 7 of the RAMA Expedi-tion. This work would not have beenpossible without the generous supportof NASA, NSF, and Sandia NationalLaboratories.

ReferencesBailey, D.M., King, N.J., Priede, I.G. 2007.

Cameras and carcasses: historical and current

methods for using artificial food falls to study

deep-water animals. Mar. Ecol., Prog. Ser.

350:179-191.

Blankenship, L.E., Yayanos, A.A., Cadien,

D.B., Levin, L.A. 2006. Vertical zonation

patterns of scavenging amphipods from the

Hadal zone of the Tonga and Kermadec

Trenches. Deep-Sea Res., Part 1. 53:48-61.

Boudrias, M.A. 2002. Are pleopods just

“more legs”? The functional morphology

of swimming limbs in Eurythenes gryllus

(Amphipoda). J. Crustac. Biol 22(3):581-94.

Bruun, A.F., Killerich, A. 1955. Characteris-

tics of the water-masses of the Philippine,

Kermadec and Tonga Trenches. In Papers in

Marine Biology and Oceanography, Dedicated

to Henry Bryant Bigelow by His Former

Students and Associates on the Occasion of the

Twenty-Fifth Anniversary of the Founding of

the Woods Hole Oceanographic Institution,

418-25. London: Pergamon Press, Ltd.

Dayton, P.K., Hessler, R.R. 1972. Role of

biological disturbance in maintaining diversity

in the deep sea. Deep-Sea Res. 19:199-208.

Haedrich, R.L., Rowe, G.T. 1977. Mega-

faunal biomass in deep-sea. Nature

269(5624):141-2.

Harvey, E.N. 1939. Deep-sea photography.

Science 90:187.

Hessler, R.R., Ingram, C.L., Yayanos, A.A.,

Burnett, B.R. 1978. Scavenging amphipods

from the floor of the Philippine Trench.

Deep-Sea Res. 25:1029-47.

Hessler, R.R., Isaacs, J.D., Mills, E.L. 1972.

Giant amphipod from the Abyssal Pacific

Ocean. Science 175(4022):636-7.

Isaacs, J.D. 1969. Nature of oceanic life. Sci.

Am. 221(3):146-62.

Isaacs, J.D., Schwartzlose, R.A. 1975.

Active animals of deep-sea floor. Sci. Am.

233(4):85-91.

Jamieson, A.J., Fujii, T., Solan, M.,

Matsumoto, A.K., Bagley, P.M., Priede, I.G.

2009. Liparid and macrourid fishes of the

hadal zone: in situ observations of activity

and feeding behaviour. Proc. R. Soc. Lond.,

B Biol. Sci. 276(1659):1037-45.

Macdonald, A.G. 1978. Further studies on

the pressure tolerance of deep-sea crustacea,

with observations using a new high-pressure

trap. Mar. Biol. 45:9-21.

Macdonald, A.G., Gilchrist, I. 1969. Recov-

ery of deep seawater at constant pressure.

Nature 222:71-2.

Mantyla, A.W., Reid, J.L. 1978. Measure-

ments of water characteristics at depths greater

than 10 km in the Marianas Trench.

Deep-Sea Res. 25:169-73.

Piccard, J., Dietz, R.S. 1961. Seven Miles

Down. New York: G.P. Putnam’s Sons.

Sessions, M.H., Marshall, P.M. 1971. A Pre-

cision Deep-Sea Time Release. SIO Reference

Series, 71-5. La Jolla, CA: University of

California, Scripps Institution ofOceanography.

Shutts, R.L. 1975. Unmanned Deep Sea Free

Vehicle System. La Jolla: Scripps Institution of

Oceanography. Marine Life Research Group.

Yayanos, A.A. 1976. Determination of the

pressure–volume–temperature (PVT) surface

of Isopar-M: a quantitative evaluation of its

use to float deep-sea instruments. Deep-Sea

Res. 23:989-93.

Yayanos, A.A. 1977. Simply actuated closure

for a pressure vessel: design for use to trap

deep-sea animals. Rev. Sci. Instrum. 48:786-9.

Yayanos, A.A. 1978. Recovery and mainte-

nance of live amphipods at a pressure of

580 bars from an ocean depth of 5700 meters.

Science 200:1056-9.

Yayanos, A.A. 1980. Measurement and in-

strument needs identified in a case history

of deep-sea amphipod research. In Advanced

Concepts in Ocean Measurements for Marine

Biology, ed. Diemer, F.D., Vernberg, F.J.,

Mirkes, D.Z., 307-18. Columbia, South

Carolina: University of South Carolina Press.

Yayanos, A.A. 1981. Reversible inactivation

of deep-sea amphipods (Paralicella caperesca)

by a decompression from 601 bars to atmo-

spheric pressure. Comp. Biochem. Physiol.

69A:563-5.

Yayanos, A.A., Nevenzel, J.C. 1978. Rising-

particle hypothesis: rapid ascent of matter

from the deep ocean. Naturwissenschaften

65:255-6.


P A P E R

Living Deep: A Synopsis of HadalTrench EcologyA U T H O R SLesley E. Blankenship-WilliamsLife Sciences Division,Palomar College

Lisa A. LevinIntegrative Oceanography Division,Scripps Institution of Oceanography

A B S T R A C TThe ocean’s deepest environments are fraught with extreme conditions, includ-

ing the highest hydrostatic pressures found on earth. The hadal zone, which en-compasses oceanic depths from 6,000 to almost 11,000 m, is located almostexclusively within deep-sea trenches. Fauna inhabiting these hadal trenches repre-sent intriguing yet possibly the least understood communities in our ocean. Wepresent a brief historical account of hadal exploration and a synopsis of the fasci-nating biogeographical trends that have emerged from 60 years of sporadic hadalsampling. Biodiversity and chemosynthesis, two important concepts in deep-seaecology, are also discussed in relation to hadal trenches.Keywords: Amphipod, Biodiversity, Biogeography, Hadal ecology, TrenchHistorical Perspective

The great depths of the oceanwere known to explorers at the timeof the Challenger Expedition (1873–1876); these intrepid scientists tooksoundings up to 8,200 m. Their inci-dental collections of fourteen differentforaminifera shells from soundingtubes suggested that that protistsmight live as deep as 7,220 m, al-though it could be not be determinedif the foraminifera were truly living atthe depth of capture (Brady, 1884).Conclusive evidence of life at depthsbelow 6 km did not occur until morethan a half a century later (Belyaev,1989). In 1948, a Swedish deep-seaexpedition aboard the Albatross recov-ered the first benthic animals (poly-chaetes and holothurians) from depthsbetween 7,625 and 7,900 m in thePuerto Rico Trench (Wolff, 1960;Belyaev, 1989). This enlightening dis-covery spawned a decade of vigoroustrench exploration, resulting in someof the most comprehensive biologicalsurveys of the world’s deep-sea trenchesto date. The Danish Galathea Deep-Sea Expedition (1951–1952) sampledin five trenches and captured animalsat depths slightly greater than 10 km

in the Philippine Trench. Beginningin 1949, many trench sampling expe-ditions were conducted aboard theSoviet vessel Vityaz, resulting in thecapture of benthic animals from10.6 km in the Tonga Trench and10.7 km in the Mariana Trench(Belyaev, 1989). In January 1960,the golden age of trench biologyreached a pinnacle when the bathy-scaph Trieste dived into the Chal-lenger Deep of the Mariana Trench.There, oceanographers Jacques Piccardand Donald Walsh traveled deeper inthe ocean than any human before orsince and observed an unidentifiedbenthic animal, confirming that alloceanic depths are inhabitable. Dur-ing this decade of discovery, it becameincreasingly evident that fauna livingdeeper than 6–7 km were distinctfrom the fauna inhabiting the shal-lower abyssal depths (4–6 km). In1956, A. Bruun first described depthsin excess of 6 km as a unique ecolog-ical realm: the hadal zone.

The hadal zone is almost exclu-sively confined to the ocean’s 37 deep-

sea trenches, the nine deepest ofwhich are located along the westernarc of the Pacific Ocean. The deepest45% of the ocean’s maximal verticalrange (which is 11 km) represents thehadal zone, although these extremedepths comprise only 1% of the sea-floor surface area. The terms hadalbiology and trench biolog y are oftenconsidered synonyms, but there is adistinction. Trench biology includesall depths within a trench, includingdepths shallower than 6 km. Con-versely, a few oceanic depressionsexist outside of trenches that slightlyexceed 6 km in depth. For this article,we discuss the biology of hadal depthswithin deep-sea trenches.

The year 2010 marks the goldenanniversary of the Trieste explorationof the ocean’s deepest depths. Thepast 50 years has brought remarkableand profound advances in almost allfacets of biological oceanography.Yet, hadal biology is still very muchin its infancy. Sending deploymentsto hadal depths is technically challeng-ing and expensive, making it diffi-


cult to collect the biological samplesnecessary to generate a thorough spe-cies list. Manipulative studies (e.g., re-cruitment experiments), so critical tounderstanding ecological function,are yet to be conducted at these depths.Consequently, our current under-standing of hadal ecological structureis akin to extrapolating the pictureprinted on a 500-piece puzzle by view-ing only a few of the puzzle pieces. Inthis sense, trench biology representsmajor frontier in deep-sea studies.

Here, we describe briefly a few ofthe major ecological paradigms thathave emerged from the intermittenthadal sampling efforts conductedover the past 60 years as well as se-lected ecological questions that remainunanswered.

Biogeography ofHadal Fauna

The extreme hydrostatic pressuresthat correlate with hadal depths neces-sitate that hadal organisms adapt bothbiochemically and physiologically tothis cold and extremely high-pressureenvironment. These adaptations areformidable. Consequently, there arecertain deep-sea fauna that appear tobe routinely excluded from invadingtrench environments. For example, or-ganisms with calcium carbonate testsor siliceous skeletons would have diffi-culty adapting to hadal environmentsas these depths exceed both the car-bonate and the opal compensationdepths. At these great depths, calcare-ous and siliceous skeletons either thinout or dissolve (Todo et al., 2005).While some taxa seem precludedfrom these depths, other invertebrateand foraminifera groups appear to tol-erate and adapt readily to extreme pres-sures. Consequently, these fauna arewell represented in most trench sam-

ples and are thought to dominate thehadal communities of the deepesttrenches (Belyaev, 1989). Foraminiferaand nematodes dominate numericallyin benthic environments (Figure 1A)(Danovaro et al., 2002; Gooday et al.,2008). Among the larger taxa, holo-thurians, polychaetes, amphipods,isopods, soft-shelled gastropods, andeven frenulate siboglinids (pogo-nophorans) are taxa typical in trenchsamples and are known to inhabit thedeepest depths. Amphipods in particu-lar are pervasive throughout the entirehadal zone (Figure 1B). Baited traps setin hadal depths can return with thou-sands of individuals of one or morespecies belonging to the Lysianassoideasuperfamily. These consistent findingsimply that the hadal scavenging guildsare absolutely dominated by a singlesuperfamily of Crustacea (Figure 2).Other important deep-sea inverte-brates such as prawns and echinodermsare known to inhabit depths between 6and 8 km but appear to be insignificantor absent at greater depths (Belyaev,1989; Jamieson et al., 2009a).

Recent observations with baitedtraps on landers have expanded ourknowledge of fish depth distribu-tions and behavior in the hadal realm( Jamieson et al., 2009b). Fish wereonce considered to be of little conse-quence to hadal communities, withthe majority of hadal fish known onlyfrom the shallowest hadal depths. In-deed, there are 15 species of fish reportedfrom depths greater than 6000 m,but the majority of these species havebroad bathymetric ranges and are con-sidered vagrants in the hadal zone.However, there are four liparid (snail-fish) species, one each in the Japan,Kurile-Kamchatka, Kermadec, andPeru trenches, that have been reportedfrom hadal depths exclusively; thesespecies are considered trench endemics(Jamieson et al., 2009b). To date, thedeepest record of fish was actuallymade by observations aboard the Ar-chimede bathyscaph in the early1960s. Observers noted the presenceof living fish on the floor of the Izu-Bonin Trench at approximately 9.2 kmand also at 8.3 km in the Puerto Rico

FIGURE 1

Examples of dominant hadal fauna. (A) A multicorer deployment at 9,941m in the Kermadec Trenchin 2001 recovered hundreds of Foraminifera specimens belonging to the genus Hyperammina, butno animals. (B) Uristes chastaini, a small lysianassoid amphipod caught in a baited trap set at7.3 km in the Tonga Trench in 2001. Removal of exoskeleton parts revealed two eggs nestledin the brood pouch (arrow). This was the first recording of hadal lysianassoid females respondingto bait while brooding. Until this discovery, hadal lysianassoid amphipods were thought to pur-posefully avoid carrion during gestation.


Trench (Belyaev, 1989). Unfortu-nately, no photographic evidence ex-ists of these observations; the fishspecies remain unidentified. Recently,the Hadal Environmental Science/Education Program (HADEEP) de-ployed baited landers to hadal depths,capturing excellent images of fish

(Pseudoliparis amblystomopsis) respond-ing to bait at 7703 m in the JapanTrench (video is available at http://www.abdn.ac.uk/mediareleases/release.php?id=1531). This is thedeepest photographic documentationof living fishes to date (Figure 3).Lander observations have revealed

that both fish and large shrimp feedon the abundant scavenging amphi-pod populations and exhibit swim-ming and activity rates surprisinglysimilar to those of their shallow-waterliparid counterparts ( Jamieson et al.,2009b).

Truly hadal fauna (those that live7 km and below) do not readily enteradjacent abyssal or bathyal environ-ments (Belyaev, 1989). The primaryforce of this “abyssal exclusion” ap-pears to be inability of hadal organismsto tolerate lower hydrostatic pressures.Decompression experiments on bothdeep-sea amphipods and bacteria cor-roborate this concept (Yayanos, 1981,1986). Accordingly, the adaptationsthat permit hadal species to inhabitsuch depths conversely prohibit ascen-sion into the adjacent abyssal plains.Since deep-sea trenches (and their re-spective hadal zones) are typicallyseparated from one another by vaststretches of bathyal or abyssal plains,many species appear to be locked intoa specific trench or group of neigh-boring trenches. Confinement of spe-cies into a single trench or a group oftrenches in close proximity undoubtedlyhas consequences for gene flow, specia-tion, and ecological structure of trenchcommunities.

One striking feature is the high de-gree of endemism that is attributed tohadal fauna as a whole and also withineach trench (Wolff, 1960). Belyaev(1989) reports that 56% of the bottom-dwelling hadal species recovered areknown to the hadal environment ex-clusively. Endemism increases withdepth. That is, the abyssal zone sharesfewer fauna with the 8 to 9 km depthgradient compared with the 6 to 7 kmgradient (Belyaev, 1989). In fact, faunafound 10 km deep in the Tonga,Mariana, and Philippine Trenches arenot known in the adjoining abyssal

FIGURE 3

Deepest living fish ever photographed. (A) Individuals of the species Pseudoliparis amblystomopsisswarm over bait placed at the seafloor in the Japan Trench at 7.7 km. (B) An individual specimen ofP. amblystomopsis from the same site. (Photos courtesy of Oceanlab University of Aberdeen).

FIGURE 2

John Isaac’s Monster Camera revealed the vigorous response of lysianassoid amphipods to baitplaced at 10.5 km in the Mariana Trench (1974). Note that the bait itself is not visible. Feedingamphipods have completely covered all surfaces of the bait while hundreds more swarm in theimmediate area. (Photo used with permission of Scripps Institution of Oceanography Archives,UC San Diego Libraries).


environments. A distinctive trend isthat trenches in close proximity (e.g.,the Tonga and the Kermadec Trenches)appear to have more species in com-mon compared with trenches thatare distantly separated. Disjointedtrenches share a very small fraction(less than 5%) of their fauna at thespecies level (Vinogradova, 1997) andthus exhibit considerable endemism(Belyaev, 1989). We note, however,that accurate estimations rely on suffi-cient sampling and most agree thatno trenches have been “sufficiently”sampled.

The origin of hadal organisms isboth a highly interesting and a highlyspeculative question. We know thatthe deep sea was approximately 10°Cwarmer in the Miocene era and ex-perienced a glacier-induced coolingas recently as 16 million years ago(Zachos et al., 2001). This significantcooling probably caused a massiveextinction of deep-sea fauna includ-ing hadal species during this time(Thomas, 2007). Therefore, currenthadal assemblages are probably theoutcome of relatively recent invasionand speciation events.

What is the source of a novel hadalspecies? Three primary repositories —abyssal fauna, other hadal fauna, andpolar fauna— are frequently proposedas source fauna, although the relativecontribution of each source is unclear.Abyssal fauna with the ability to adaptto greater hydrostatic pressures wouldcertainly be one source of new species,and several abyssal species (e.g., thelarge amphipod Eurythenes gryllus)have populations residing in the up-per limits of the hadal zone (Belyaev,1989; Blankenship et al., 2006). Exist-ing hadal fauna are also likely can-didates. If a hadal species somehowemigrated into a different trench, thisnew population would be exposed to

a different array of environmental con-ditions (i.e., nutrient input, bottomtopography, community structure).Adapting to a new environment couldeventually lead to speciation. Today,deep water masses that circulate throughmost of the trenches (especially theWestern Pacific trenches) largely origi-nate at high latitudes. Antarctic BottomWater, for example, most certainlyinfluences trenches in the southernhemisphere; this is evident from tem-perature profiles. Hyperpiezophilic(ultra pressure-loving) bacteria re-cently cultured from the KermadecTrench (located between the 25°Sand the 35°S latitudes) show theclosest relative to be a psychrophile(cold-loving species) identified fromthe shallow waters of Antarctica(Lauro et al., 2007). Interestingly, thetrench with the lowest degree of hadalendemism is the South SandwichTrench at an estimated 37% (Belyaev,1989). This trench is distinguished forits sub-Antarctic positioning and thusproximity to shallow-water Antarcticspecies.

The relatively large degree of trenchendemism (taxa endemic to a singletrench) is reduced to an average of10% when considering genera insteadof species (Belyaev, 1989). Thus, indi-vidual trenches contain unique faunalassemblages at the species level, butnot necessarily at the genus level.This trend hints at relatively recentspeciation of hadal fauna. Yet the ca-pacity for gene flow between trenchesor between a trench and its adjacentabyssal area is unknown. As an example,the Tonga Trench and the KermadecTrench (located in the SW PacificOcean) are connected by a sill that is5.2 km at its deepest point. Thus, ahadal organism migrating betweenthese trenches would need to ascendto at least 5.2 km to traverse the sill

connecting the Tonga and the KermadecTrenches. Both trenches contain ro-bust populations of the mobile scav-enging amphipod Hirondellea dubia;the vertical upper limit for this spe-cies is determined to be approximately7 km based on response to baited traps(Blankenship et al. 2006). To whatextent, then, do these two trench popu-lations mingle? If early life stages arecapable of surviving such an ascent,then gene flow could be quite high. Ex-treme pressure tolerances are knownin larvae of some invertebrates (Mestreet al., 2009) but not others (Young andTyler, 1993). For instance, the juvenilestages of at least two trench amphipodspecies (including H. dubia) exist pri-marily in the shallower depths of the spe-cies’ vertical distribution (Blankenshipet al., 2006). Thus, the younger indi-viduals appear to have greater dis-persal potential compared with matureadults. Yet it is also possible that thetwo trench amphipod populationshave been isolated completely intotheir respective trenches for thousandsof years or more. In the latter scenario,gene flow between the two trencheswould be zero. That we lack the infor-mation to address such questions em-phasizes just how little is known abouthadal ecology.

Biodiversity: High or Low?A single hadal sample typically re-

turns with low diversity and oftenlow biomass if collected from an oligo-trophic area. Indeed, some deep coresamples have returned devoid of a sin-gle animal. It is not surprising that thegeneral perception of the hadal en-vironment is one of exceedingly lowbiodiversity (Grassle, 1989). An ap-preciation for the exclusionary forceof extreme hydrostatic pressures oncertain deep-sea taxa only reinforces


this notion. Cumulatively, however,the trenches represent an importantrealm of speciation andmay contributesignificantly to deep-sea biodiversity.The isolation of species into individualtrenches appears to restrict gene flow,thus facilitating a relatively high rateof speciation as suggested by highrates of endemism. Moreover, the het-erogeneity of habitats in trenches is un-derappreciated. Trench walls are steepand jagged, exposing numerous out-croppings of hard substrate interspersedamong localized pockets where sedi-ment accumulates. Trenches are re-gions of high tectonic activity andtherefore possibly places to supportchemosynthesis where sulfide or meth-ane escape (e.g., the seep communitydiscovered at 7,300 m in the JapanTrench; Fujikura et al., 1999). Theunusual isolation, distribution, andgeomorphology of trenches offer ex-ceptional opportunities to test ecolog-ical and evolutionary theories aboutspeciation, community assembly,and ecosystem function (Levin andDayton, 2009).

To date, most sampling efforts havefocused on the areas that are logisticallyaccessible: the flat and soft benthosthat accumulate in the trench axisand, to a lesser degree, the pelagicfauna in trawls. Technical advance-ments in sampling or observationalapparatus, such as pressure-tolerantcameras (Figure 4), landers, or re-motely operated vehicles capable ofdescending to all hadal depths, may re-veal numerous microhabitats alongwith novel fauna inhabiting these yet-unexplored areas.

The importance of vertical zona-tion, ambient water temperature, andnutritional input are potential butpoorly understood drivers of biodiver-sity ( Jumars and Hessler, 1976;Vinogradova, 1979; Gambi et al.,

2003). Deep-sea trenches are extremelysteep; a relief of thousands of meters(and corresponding changes in phys-ical parameters such as pressure andtemperature) can occur over a fewhorizontal kilometers. In the TongaTrench, four species of scavenginglysianassoid amphipods recoveredfrom the hadal zone vertically partitionthe hadal depths (Blankenship et al.,2006). This vertical partitioning ofhabitat by amphipod species, similarto the zonation patterns observed onseamounts, may be a mechanism to fa-cilitate coexistence of four similar spe-cies, thus increasing the biodiversity ina single trench. Ambient water temper-ature, which ranges from 0 to 4.5°C, isoften ignored in the discussion oftrench community structure and speci-ation. Yet, even temperature changesof a few degrees may factor into an or-ganism’s tolerance for a particular en-vironment and therefore govern itsdistribution (Yayanos, 1986). The in-fluence of temperature on an organism’sdistribution and therefore speciationand biodiversity should not be dis-counted without further studies. Like-wise, productivity in overlying waters

is roughly correlated to benthos biomass,which probably impacts communitystructure and therefore biodiversity.Trenches under highly productivewaters (termed “eutrophic trenches”)receive and concentrate large quanti-ties of organic input (Danovaro et al.,2003). This may be both boone andbane to trench bottom fauna. On onehand, the more abundant and diversefood supply may support a greaterbiomass. For example, beneath theworld’s most productive waters offPeru and Chile, the Atacama Trenchsupports higher densities of meiofaunaat 7800 m than at 1050–1350 m(Danovaro et al., 2003; Gambi et al.,2003). On the other hand, the steepslopes of these trenches serve to con-centrate this matter in what becomesa sediment trap. Tectonic activity cre-ates periodic mudslides off the deepslopes, sending a disproportionatelylarge amount of sediment and organicmaterial into the trench axis. Thesedisturbances are speculated to bea major contributing factor to lowspecies diversity in eutrophic trenchbottom fauna ( Jumars and Hessler,1976; Grassle, 1989). However, the

FIGURE 4

(A) A pressure-tolerant camera system capable of withstanding depths up to 10 km is shown inthe Deep Tank at Scripps Institution of Oceanography (2001). (B) An enlarged view of a pelagicsea spider (Pycnogonida) captured in the distance by the same camera system deployed in theAleutian Trench (2005). Although the particular photo was taken at non-hadal depths duringascent, this revolutionary camera is capable of taking hundreds of quality photographs duringhadal deployments. (Photos courtesy of Georgia Ratcliffe and Kevin Hardy).


true effect of eutrophic input on trenchbiodiversity is still undetermined.

Chemosynthesis inHadal Trenches?

The tectonic events within trenchescan trigger turbidity flows and massiveslope instability. Therefore, it shouldnot be surprising to find methane emis-sions and exposed sulfidic sedimentsalong the rims, walls, and ledges oftrenches. Where this occurs, methaneseeps support dense assemblagesof symbiont-bearing clams that relyon reduced compounds from below(rather than organic matter from sur-face waters) for their nutrition. Thereare large vesicomyid clams reportedfrom the abyssal zone sections of theAleutian Trench (Rathburn et al., 2009)and from Sanriku Escarpment of theJapan Trench at 6437 m (Fujikuraet al., 1999), but at the deepest knownseep in the Japan Trench at a depthof 7326 m, the dominant clams arethyasirids (Fujiwara et al., 2001). Aswith all seeps, biomass appears to bevery high for the depths involved.Common hydrothermal vent taxasuch as mussels and tubeworms arenot reported from trenches. We donot know yet whether methane seepproduction reaches the non-seep (am-bient) trench animals, but mobile taxalike amphipods could possibly use andtransfer this production to the sur-rounding trench ecosystem.

We speculate that seep communi-ties, which are wide spread along Pacificmargins at shallower depths (Levin,2005), will turn out to be very abun-dant at hadal depths in tectonicallyactive trenches. Such environmentsmay host new species not yet describedfrom seeps. However, seep environ-ments are extremely patchy and local-ized at all depths and thus difficult to

locate. Their discovery and explorationwill require use of ship surveys to de-tect methane plumes and systematicautonomous underwater vehicle orcamera sled transects once evidenceof methane is found. If more seepsare found at hadal depths, we may dis-cover novel animal–microbe interac-tions shaped by high pressure.

These Remote DepthsRemain a Mystery

The hadal trenches and the biologyand ecology of the creatures that in-habit them remain one of the least un-derstood marine environments. Eachexpedition greatly adds to our knowl-edge, sometimes shattering old pa-radigms but more often leading tomore questions than answers (see Fig-ure 1b). For example, the multitude ofamphipods that live in the deepestparts of trenches were once thoughtto be obligate scavengers. Throughnew molecular techniques, these am-phipods are now known to be quiteresourceful foragers—feasting on anarray of diet items, including theirfellow amphipods, phytoplankton,other invertebrates, fish, and even adairy cow that somehow made its wayonto a trench bottom (Blankenshipand Levin, 2007). The latter findingdemonstrates that trenches, althoughremote, are not immune to anthropo-genic influence. However, because wehave no baseline to build from, wecannot ascertain how our presence in-fluences trench communities. Truly,we are still in the “exploratory phase”of research in this fascinating realm.

AcknowledgmentsThe authors thank Kevin Hardy

and Monte Priede for providing

photographs for this article and espe-cially Kevin for his boundless enthusi-asm for trenches and his dedication toassembling this special volume. Theyalso thank three anonymous reviewsfor their thoughtful and constructivecomments which improved the manu-script significantly.

ReferencesBelyaev, G.M. 1989. Deep-Sea Ocean

Trenches and Their Fauna. Moscow: Naika

Publishing House, 385pp. (Translated to

English by Scripps Institution of Oceanogra-

phy, USA, 2004).

Blankenship, L.E., Yayanos, A.A., Cadien,

D.B., Levin, L.A. 2006. Vertical zonation

patterns of scavenging amphipods from the

hadal zone of the Tonga and Kermadec

Trenches. Deep-Sea Res., Part 1. 53:48-61.

Blankenship, L.E., Levin, L.A. 2007.

Extreme food webs: foraging strategies and

diets of scavenging amphipods from the

ocean’s deepest 5 kilometers. Limnol.

Oceanogr. 52:1685-1697.

Brady, H.B. 1884. Report on the foraminifera

dredged by H.M.S. Challenger during the

years 1873–1876. Report of the scientific

results of the voyage of H.M.S. Challenger,

1873–1876. Zoology. 9:1-814.

Bruun, A.F. 1956. The abyssal fauna: its

ecology, distribution and origin. Nature.

177:1105-1108.

Danovaro, R., Gambi, C., Della Croce, N.

2002. Meiofauna hotspot in the Atacama

Trench, eastern South Pacific Ocean. Deep-

Sea Res., Part 1. 49:843-857.

Danovaro, R., Della Croce, N., Dell’Anno,

A., Pusceddu, A. 2003. A depocenter of

organic matter at 7800 m depth in SE

Pacific Ocean. Deep-Sea Res., Part 1.

50:1411-1420.

Fujikura, K., Kojima, S., Tamaki, K., Maki,

Y., Hunt, J., Okutani, T. 1999. The deepest

chemosynthesis-based community yet dis-

covered from the hadal zone, 7326 m deep,


in the Japan Trench. Mar. Ecol., Prog. Ser.

190:17-26.

Fujiwara, Y., Dato, C., Masui, N., Fujikura,

K., Kojima, S. 2001. Dual symbiosis in the

cold-seep thyasirid clam Maorithyas hadalis

from the hadal zone in the Japan Trench,

western Pacific. Mar. Ecol., Prog. Ser.

214:151-159.

Gambi, C., Vanreusel, A., Danovaro, R.

2003. Biodiversity of nematode assemblages

from deep-sea sediments of the Atacama Slope

and Trench (south Pacific Ocean). Deep-Sea

Res., Part 1. 50:103-117.

Gooday, A., Todo, Y., Uematsu, K., Kitazato,

H. 2008. New organic-walled Foraminifera

(Protista) from the ocean’s deepest point, the

Challenger Deep (western Pacific Ocean).

Biol. J. Linn. Soc. 153:399-423.

Grassle, J.F. 1989. Species diversity in deep-sea

communities. Trends Ecol. Evol. 4:12-15.

Jamieson, A.J., Fujii, T., Solan,M.,Matsumoto,

A.K., Bagley, P.M., Priede, I.G. 2009a.

First findings of decapod crustacea in the

hadal zone. Deep-Sea Res., Part 1.

56:641-647.

Jamieson, A., Fujii, T., Solan,M.,Matsumoto,

A.K., Bagley, P.M., Priede, I.G. 2009b. Liparid

and macrourid fishes of the hadal zone:

in situ observations of activity and feeding

behavior. Proc. R. Soc. Lond., B Biol. Sci.

276:1037-1045.

Jumars, P.A., Hessler, R.R. 1976. Hadal

community structure: implications from the

Aleutian Trench. J. Mar. Res. 34:547-560.

Lauro, F. M., Chastain, R.A., Blankenship,

L.E., Yayanos, A.A., Bartlett, D.H. 2007. The

unique 16S rRNA genes of piezophiles reflect

both phylogeny and adaptation. Appl. Envi-

ron. Microbiol. 73:838-845.

Levin, L. A. 2005. Ecology of cold seep

sediments: Interactions of fauna with flow,

chemistry, and microbes. Oceanogr. Mar.

Biol. 43:1-46.

Levin, L.A., Dayton, P.K. 2009. Ecological

theory and continental margins: where shallow

meets deep. Trends Ecol. Evol. 24:606-617.

Mestre, N.C., Thatje, S., Tyler, P.A. 2009.

The ocean is not deep enough: pressure

tolerances during early ontogeny of the blue

mussel Mytilus edulis. Proc. R. Soc. Lond.,

B Biol. Sci. 276:717-726.

Rathburn, A.E., Levin, L.A., Tryon, M.,

Gieskes, J.M., Martin, J.B., Pérez, M.E.,

Fodrie, F.J., Neira, C., Mendoza, G.,

McMillan, P.A., Adamic, J., Kluesner, J.,

Ziebis, W. 2009. Geological and biological

heterogeneity of the Aleutian Margin

(1965-4822 m) Progr. In Oceanography,

80:22-50.

Thomas, E. 2007. Cenozoic mass extinctions

in the deep sea; what disturbs the largest

habitat on Earth? In: Large Ecosystem

Perturbations: Causes and Consequences,

Eds., Monechi, S., Coccioni, R., Rampino,

M. Geological Society of America Special

Paper, 424.

Todo, Y., Kitazato, H., Hashimoto, J.,

Gooday, A.J. 2005. Simple foraminifera

flourish at the ocean’s deepest point. Science.

307:689.

Vinogradova, N.G. 1979. The geographical

distribution of the abyssal and hadal (ultra-

abyssal) fauna in relation to the vertical

zonation of the ocean. Sarsia 64:41-50.

Vinogradova, N.G. 1997. Zoogeography of

the abyssal and hadal zones. Adv. Mar. Biol.

32:325-387.

Wolff, T. 1960. The hadal community, an

introduction. Deep-Sea Res. 6:95-124.

Yayanos, A.A. 1981. Reversible inactivation

of deep-sea amphipods (Paralicella capresca) by

decompression from 601 bars to atmospheric

pressure. Comp. Biochem. Physiol., A.

69:563-565.

Yayanos, A.A. 1986. Evolutional and ecolog-

ical implications of the properties of deep-sea

barophilic bacteria. Proc. Natl. Acad. Sci.

U. S. A. 83:9542-9546.

Young, C. M., Tyler, P.A. 1993. Embryos of

the deep-sea echinoid Echinus affinis require

high pressure for development. Limnol.

Oceanogr., 38:178-181.

Zachos, J., Pagani, M., Sloan, L., Thomas, E.,

Billups, K. 2001. Trends, rhythms, and

aberrations in global climate change 65 Ma

to present. Science. 292:686-693.


P A P E R

Deep Sound: A Free-Falling SensorPlatform for Depth-Profiling AmbientNoise in the Deep OceanA U T H O R SDavid R. BarclayFernando SimonetMichael J. BuckinghamMarine Physical Laboratory,Scripps Institution of Oceanography,University of California, San Diego

A B S T R A C TAmbient noise in the deep ocean is traditionally monitored using bottom-

mounted or surface-suspended hydrophone arrays. An alternative approach has re-cently been developed in which an autonomous, untethered instrument platformfree falls under gravity from the surface to a preassigned depth, where a drop weightis released, allowing the system to return to the surface under buoyancy. Referred toas Deep Sound, the instrument records acoustic, environmental, and system datacontinuously during the descent and ascent. The central component of Deep Soundis a Vitrovex glass sphere, formed of two hemispheres, which houses data acqui-sition and storage electronics, along with a microprocessor for system control. Asuite of sensors on Deep Sound continuously monitor the ambient noise, temper-ature, salinity, pressure, and system orientation throughout the round trip from thesurface to the bottom. In particular, several hydrophones return ambient noise timeseries, each with a bandwidth of 30 kHz, from which the noise spectral level, alongwith the vertical and horizontal coherence, are computed as functions of depth. Aftersystem recovery, the raw data are downloaded and the internal lithium ion batteriesare recharged via throughputs in the sphere, which eliminates the need to separatethe hemispheres between deployments. In May 2009, Deep Sound descended to adepth of 6 km in the Philippine Sea and successfully returned to the surface, bring-ing with it a unique data set on the broadband ambient noise within and below thedeep sound channel. The next deep deployment is planned for November 2009,when Deep Sound will descend almost 11 km, to the bottom of the ChallengerDeep at the southern end of the Mariana Trench. If successful, it will return withcontinuous acoustic and environmental recordings taken from the sea surface tothe bottom of the deepest ocean on Earth.

Introduction

Deep Sound, shown in Figure 1,is an autonomous, untethered, free-falling instrument platform designedto descend under gravity from the seasurface to a depth of 9 km. After re-leasing an expendable, cast-iron dropweight, it then returns to the surfaceunder buoyancy. The descent and the

ascent rates are similar at about 0.6m/s.A Vitrovex glass sphere, with externaland internal diameters of 43.2 and39.6 cm, respectively, and 3.6 cmthick, houses data acquisition, datastorage, and power management elec-tronics along with lithium ion batteries.

Outside the sphere, hydrophonesmounted in vertical and horizontalalignments detect the ambient noisefield continuously throughout the de-scent and the ascent. Additional sen-

sors are mounted on Deep Sound forcontinuous monitoring of temper-ature, depth, and salinity (hencesound speed) as well as the pitch, roll,and yaw of the platform itself. All thedata recorded by the system during thedeployment are downloaded after re-covery of the system via a USB datalink passing through the Vitrovexsphere. Another throughput allowsthe batteries to be recharged withouttheir removal from the sphere.

FIGURE 1

Deep Sound Mk. I, photographed during atethered engineering test in 100 m water offthe coast of La Jolla, Southern California.


A high-densi ty polyethylene(HDPE) casing not only protects thesphere but also provides a mountingstructure for the hydrophones, alongwith the environmental and systemsensors. To aid deployment and recov-ery of Deep Sound, a titanium bail isattached to the HDPE casing, and ahigh-intensity strobe light, a radio bea-con, and an Argos GPS antenna allhelp to locate the system when it re-turns to the surface.

During deployment, acoustic data,environmental data, and system data,such as internal temperature, remain-ing battery life, and system orienta-tion, are centrally processed on anembedded microprocessor, which liesat the heart of the instrument’s elec-tronics. This processor also triggersthe burn wire switch based on incom-ing depth data. In the event that theburn wire is not triggered at the presetdepth, a number of fail-safe mecha-nisms are built into the system to ensurethat the drop weight is indeed released.

Two versions of Deep Sound, des-ignated Mk. I and Mk. II, have beenbuilt and successfully tested in thefield. The Mk. II has several improvedfeatures over the Mk. I, including fourhydrophones instead of two, and a si-lent solid-state memory rather than theoriginal, mechanically noisy hard disk.To date, the deepest descent has beenachieved with theMk. I version, whichreached a maximum depth of 6 km inthe Philippine Sea in May 2009and returned to the surface after a6-h round trip.

The Deep Sound Channeland Ambient Noise

Deep Sound was developed to pro-file the ambient noise in the oceanfrom the surface to the greatestdepth, which is approximately 11 km

in the Challenger Deep at the southernend of the Mariana Trench. Much ofthe noise in the ocean is generated byacoustic sources near the sea surface,including surface ships and bubblescreated by breaking waves (Wenz,1962). A sound ray from a surfacesource penetrates down into theocean, following a path that is curveddue to refraction arising from thedepth-varying sound speed.

In deep water, the primary factorsaffecting the speed of sound are tem-perature and pressure. A schematic ofa deep-water sound speed profile isshown in Figure 2. With increasing

depth, the temperature decreases giv-ing rise to a corresponding decreasein the speed of sound. Eventually,however, the effect of pressure be-comes dominant, causing the soundspeed to increase with further increasesin depth. The net effect is a soundspeed profile that exhibits a pro-

nounced minimum, as illustrated inFigure 2. In temperate waters, thesound speed minimum occurs atdepths of approximately 1000 and700 m, respectively, in the Atlanticand Pacific Oceans.

The sound speed profile acts like alens, causing sound rays to bend to-wards regions of lower sound speed.As a result, a deep-water sound speedprofile forms a waveguide, known asthe deep sound channel, trappingrays around the minimum, or channelaxis. It is possible to propagate soundthrough the deep sound channel overthousands of kilometers (Ewing and

Worzel, 1948; Munk et al., 1995)since the attenuation is minimal inthe absence of acoustic interactionswith the sea surface and sea bed.

Points with the same sound speedon either side of the channel axis are re-ferred to as conjugate depths, and thesurface conjugate depth is known as

FIGURE 2

Sketch of a deep-ocean sound speed profile showing the sound channel axis, two conjugate depths,and the critical depth.


the critical depth (Figure 2). Accordingto Weston (1980), at upper and lowerconjugate depths, the ambient noisefields have similar properties, andbelow the critical depth, the noisefrom surface sources is thought todecay to a negligible level. In equatorialand temperate waters, the criticaldepth is in the region of 5 km. Atsuch great depth, it is difficult to con-firm Weston’s predictions due to thedifficulty of deploying conventionalcabled and moored arrays in such ahostile environment. Consequently,the available data on the depth depen-dence of deep-water ambient noise aresparse (Gaul et al., 2007; Morris,1978).

Deep Sound has the capability ofdescending well below the criticaldepth, recording the ambient noisefield continuously as it progresses. Theraw acoustic data collected by the systemmay be processed to yield the ambientnoise spectrum level as a continuousfunction of depth over a frequencyband from 3 Hz to 30 kHz. A depthprofile of the vertical coherence of theambient noise over a similar bandwidthmay also be obtained, thus providing ameasure of the vertical directionality ofthe noise as a function of depth and fre-quency. Such information is needed totest the validity of the various deep-water ambient noise models that nowexist, including Weston’s.

Design Criteria for DeepSound

To operate at the greatest depthsfor periods of several hours, DeepSound had to meet a number of de-manding design criteria. First andforemost, it had to be capable of with-standing enormous pressures, up tothe equivalent of 1,100 atmospheres,encountered at the bottom of the

Challenger Deep. In both the Mk. Iand the Mk. II versions of DeepSound, a Vitrovex glass sphere was se-lected as the pressure casing. Thesphere also provides the main sourceof buoyancy. For ease of deploymentand recovery, the system had to besmall and light enough for two peopleto manhandle over the side of a boatusing a small davit (Figure 1). Sincethe two versions of Deep Sound thathave been built are similar to one an-other, the Mk. I will be describedfirst, followed by a brief account ofthe modifications that were introducedinto the Mk. II.

Deep Sound Mk. IThe Vitrovex glass sphere, with a

maximum depth rating of 9 km, is ac-tually comprised of two hemisphereswith flat, polished surfaces of contact.No O-rings are necessary to seal thejoin, which is kept watertight by hy-drostatic pressure. The hemispheresare kept in register with Henkel adhe-sive and a single wrap of 3M Scotchrap50, with a vacuum pulled on thesphere through one of its ports. Besidesthe vacuum port, the sphere has sevenports for electrical bulkhead connec-tors and a further feedthrough for theinternally housed pressure sensor. Thebulkheads connect the external sensorsto the internal data acquisition hard-ware as well as providing interfac-ing for data downloading and batteryrecharging.

For protection and handling, thesphere is encased in an HDPE hardhat, to which is bolted a titanium bailand an HDPE frame. Two HDPEarms extend away from the frame (Fig-ure 1) and hold the two hydrophonesout of the wake of themain body of theinstrument. The hydrophones are ver-tically aligned with a separation of0.5 m. The overall footprint of the in-

strument is 0.6 × 0.6 m, with a heightof 1 m and a total mass in air of 68 kg.The buoyancy is 215N, which providesa steady ascent rate of 0.6 m/s, and a21-kg cast-iron drop weight providesa matching descent rate of 0.6 m/s.At this speed, the round trip from thesurface to a depth of 9 km takes 8 hand 20 min.

Data acquisition, data storage,power management, and burn wirecontrol are coordinated by an ArcomApollo EBX motherboard with a low-powered, fanless Intel Pentium MCPU. The two simultaneously sam-pled channels of acoustic data areacquired through a National Instru-ments PCI-4462 analogue-to-digitalconverter with 100 kHz acoustic band-width and 24 bit dynamic range. Thepressure and temperature data are re-corded, respectively, via serial andUSB ports. The Windows XP Embed-ded operating system and software runfrom a 2-Gbyte compact flash card,while data storage is provided by aUSB-connected 150-Gbyte hard disk.

An OceanServer TechnologyBA95HC power management unitcomprised of four lithium ion batteriespowers the motherboard and the indi-vidual components of Deep Sound.The appropriate voltages for each com-ponent are provided by ATX DC/DCand Vicor Power DC/DC converters,while battery condition is monitoredby the main system via a serial portcontroller. The battery pack is ratedat 95 Wh, which allows Deep Soundto operate continuously for 9.5 h.Power is isolated by another DC/DCconverter and channeled by the parallelport to the burn wire. A separate circuitwith an independent timer, a 9-V bat-tery and an isolated DC/DC converter,provides backup power to the burnwirein the event that the main system soft-ware or hardware fail. The expendable


burn wire is fabricated from Seven-Strand Sevalon 250WN nylon-coatedstainless steel fishing line.

After the glass sphere has been as-sembled, an external magnetic switchis used to boot the system. Once run-ning, an external computer can net-work with Deep Sound through anEthernet bulkhead connector or byusing a wireless ad-hoc connection.Data may be downloaded by network-ing a hard disk to the system through aUSB bulkhead connector. The systemmay be shut down from a remotelynetworked computer or the powercan be cut with the magnetic switch.

The two acoustic sensors used inDeep Sound Mk. I are Hi-Tech HTI94 SSQ hydrophones mounted onthe HDPE casing with 0.5 m verticalseparation. Each of the phones, inde-pendently calibrated over a frequencyband from 2 Hz to 30 kHz, shows aflat frequency response of approxi-mately −165 dB referenced to 1 μPa.The phones are also calibrated over pres-sures up to 600 bar, corresponding toa maximum ocean depth of 6,000 m.Hi-Tech Inc. specifies the maximumoperating depth of their HTI 94SSQ phone as 6096 m, but our ownindependent tests, using the pressurechamber at Deep Sea Power andLight, show that the HTI 94 SSQfunctions satisfactorily under muchgreater pressure, equivalent to a depthof 12 km. Little change in the calibra-tion occurs with increasing pressure.

The operating depth of DeepSound is determined using a Parosci-entific Pressure Sensor 9000-20K,which is mounted inside the glass sphereand measures hydrostatic pressurethrough a titanium bulkhead. Sea wa-ter temperature is measured with aSeabird SBE 38 Digital OceanographicThermometer, which is mounted ex-ternal to the sphere and is rated to a

maximum depth of 10.5 km. Everyhalf second, temperature and depthare recorded and, from both measure-ments, sound speed is estimated.

An Ocean Server compass inter-faced to the motherboard via a USBconnection is used to measure thepitch, roll, and yaw of the platform.These data are useful in the diagno-sis and correction of undesirable sys-tem motions during the descent andascent.

To aid in locating and recoveringthe instrument after it returns to thesurface, three Novatech systems aremounted on the HDPE casing abovethe glass sphere: an ST-400AR XenonFlasher, an RF-700AR Radio Beacon,and an AS-900A Argos Beacon. Thexenon flasher is a high-intensity strobelight that has proved to be invaluablefor visual sighting during a nighttimerecovery. The radio beacon broadcastsan intermittent tone, allowing a ship-board radio detection finder to deter-mine the bearing to the instrument.The Argos beacon uses GPS satellitenavigation to determine the instru-ment’s position coordinates (latitudeand longitude), which are then trans-mitted to an online server. Each ofthese systems has a pressure switch toensure operation only when DeepSound has returned to the surface.The Novatech systems all have thesame type of pressure housing, whichis rated to a maximum depth of7.5 km by the manufacturer. However,in our own independent pressure testsat Deep Sea Power and Light, theRF-700AR Radio Beacon and antennamodule were subjected to pressures ashigh as 1,100 bar (equivalent to adepth of 11 km) without failure.

Deep Sound Mk. IIThe design of the Mk. II version

of Deep Sound is similar to that of

the Mk. I, but with the followingimprovements.

A Kontron 986LCD-M/mITXmotherboard with a low-power, fanlessIntel Celeron CPU is used because ithas half the power consumption ofthe original Arcom unit. For data stor-age, a silent 128-Gbyte solid-statememory chip replaces the mechanicallynoisy hard disk. In place of individualtemperature and pressure sensors,Deep Sound Mk. II has a FalmouthScientific Standard 2 Micro conductiv-ity, temperature, and depth sensor,with a depth rating to 9 km, which re-turns salinity in addition to tempera-ture and depth measurements.

Deep SoundMk. II has four acous-tic channels, with the HTI 94 SSQ hy-drophones arranged in an “L” shape.Three of the phones are aligned inthe vertical and two in the horizontal,with one phone common to both con-figurations. The spacings between thephones are adjustable, ranging from0.3 to 1 m. The horizontally alignedphones yield the horizontal coherenceof the ambient noise, which is relatedto the horizontal directionality, whilethe additional phone in the verticalprovides enhanced angular resolutionas well as returning information onthe spatial homogeneity of the noise.

The Deployment PhaseDeep SoundMk. I andMk. II both

run National Instruments LabViewsoftware to coordinate operations dur-ing deployment. After the instrument ispowered up using the magnetic switch,a remotely networked computer setsvarious deployment parameters. Priorto use, the LabView program is assigneddepths at which to start and stop record-ing and a depth at which to drop theballast weight. Sample rates, dynamicrange, and data acquisition parameters


are adjustable through this program.Visual displays of the real-time outputof the hydrophones, along with batterylife and system temperature, show theoperator that the various componentsof the instrument are functioningcorrectly.

Two countdown timers are activatedon start up: one with a length that is ad-justable in the LabView program andthe other on an independent circuit,with a length that can only be changedby separating the glass spheres and ad-justing a variable resistor. Both timersare fail-safe devices. If either timerreaches zero, the burn wire will be ac-tivated and the ballast weight dropped,allowing the system to return to thesurface under buoyancy.

Once deployed in the water, thedata acquisition system remains idleuntil reaching the start depth, as deter-mined by the pressure sensor. At thispoint, continuous data recording dur-ing free-fall begins. When the instru-ment reaches the preassigned dropdepth, a voltage is activated on theburn wire, which oxidizes to thepoint of mechanical failure in lessthan one minute. The weight thenfalls away and the instrument beginsto ascend while continuing to acquireacoustic, environmental, and systemdata. Near the surface, when thethird preassigned depth is reached,the data acquisition software shutsdown and the system returns to idle.Upon arrival at the surface, indepen-dent pressure switches activate thexenon strobe, the radio beacon, andthe Argos beacon.

The Deep Sound LabView pro-gram incorporates the incoming datainto real-time decision making, aboveand beyond the routine deploymentprocedures. The main purpose of thedecision-making function is to avoidthe loss of Deep Sound due to errors

that may occur in individual systemcomponents. Battery life and systemtemperature (inside the glass sphere)are monitored and if a low-batterythreshold is crossed or if the system be-gins to overheat, data acquisition is ter-minated and the remaining powerapplied to the burn wire. In the eventof a software or hardware error, such asa data buffer overflow, full data stor-age, or a non-responding peripheral,operations cease and the burn wire isactivated. Descent and ascent ratesare continuously monitored, and if sig-nificant changes are detected or if theinstrument hits the sea bed beforereaching the preprogrammed ballast-weight drop depth, the burn wire isactivated.

The Lab View program is easily al-tered, allowing Deep Sound to be de-ployed in a variety of modes withoutopening the glass sphere or modifyingthe control hardware. For example,with the descent-speed monitoringdisabled, Deep Sound could sit onthe sea bed for a specified time beforestarting its return to the surface, or toconserve power and extend the deploy-ment time, Deep Sound could beprogrammed to record data on a dutycycle. Outside the sphere, the acousticchannels are modular, capable of sup-porting any type of sensor with a band-width up to 100 kHz in place of thehydrophones. Indeed, the design phi-losophy underlying Deep Sound hasbeen the development of a deep-divingplatform with software and hardwarearchitectures that provide flexibilityin terms of data acquisition, mode ofdeployment, and sensor pay load.

Deep Sound Mk. Iin the Philippine Basin

The first deep deployments ofDeep Sound were made in May 2009

during theNorth Pacific Acoustic Lab-oratory experiment in the PhilippineBasin. Operating from the R/V KiloMoana, three descents were made todepths of 5,100, 5,500, and 6,000 m.On each occasion, the system de-scended to maximum depth, releasedthe ballast weight, and successfully re-turned to the surface. Acoustic andenvironmental data were recorded con-tinuously during each of the roundtrips. Figure 3 shows the depth versustime trajectory of the system and themeasured sound speed profiles for thethird and deepest drop.

During the descent and ascent,Deep Sound measured the ambientnoise field on the two vertically sepa-rated hydrophones over a frequencyband extending to 30 kHz. Althoughboth the sensors were placed outsidethe wake produced by the main instru-ment housing, one of the phones wasalways in the wake of the other, withthe result that excess flow noise ap-peared on the trailing hydrophone.By comparing the spectra from thetwo acoustic channels, the effect ofthe flow on the output of the trailingphone becomes apparent, as illustratedin Figure 4. At frequencies below1 kHz, the trailing phone shows a spec-tral level some 10 dB above that of theleading phone, although above 10 kHzthe excess decreases to about 5 dB. Inthis particular case, the system was des-cending and the top phone exhibitedthe excess noise. A similar excess-noisephenomenon occurs in the ascent butwith the lower phone returning thehigher spectral level.

Since returning from the PhilippineSea, the Mk. I and Mk. II systems havebeen modified by fitting open-porefoam flow shields around the hydro-phones. These tailor-made flow shieldsare highly effective at reducing theturbulence-induced noise to negligible


levels across the whole frequency bandshown in Figure 4. In effect, the flowshields trap still water around thephones, keeping the turbulent flow ata distance from the active faces of thesensors.

Future Deploymentand Developmentof Deep Sound

Since the successful deployment ofDeep Sound Mk. I to a depth of 6 kmin the Philippine Sea, the Mk. II ver-sion, with four acoustic channels, hasbeen tested in the shallow ocean offthe coast of La Jolla, southern Califor-nia. Both systems are now ready for thenext deep deployment, which is sched-uled for November 2009 in the Chal-lenger Deep at the southern end of theMariana Trench. The ocean at this lo-cation is the deepest in the world at justunder 11 km. The Vitrovex glassspheres in both systems are rated bythe manufacturers to 9 km. Followinga cautionary plan, the Mk. I. andMk. II systems will first be deployedwithin specifications to a maximumdepth of 9 km. Assuming a successfulreturn to the surface, the batteries ofMk. I will be recharged, taking a littleless than 3 h, and the system sent downagain, but this time to within 100 m ofthe bottom. Thus, the maximum de-ployment depth in this deepest of deepdescents will be around 10,800 m,corresponding to a round trip traveltime of 10 h. One or more hydro-phones near the surface will listen forthe sound of an implosion, which, ifit were to happen, would be usefulfor failure diagnosis.

A third version of Deep Sound, theMk. III, is currently in the planningstage. This new instrument will use aVitrovex glass sphere of diameter

FIGURE 4

Ambient noise spectra from the Philippine Basin deployment, taken while Deep Sound Mk. Idescended from a depth of 5667 to 5679 m. The higher level of the spectrum from the trailinghydrophone is due to flow noise from turbulence generated by the leading phone.

FIGURE 3

(a) The depth versus time profile of Deep Sound Mk. I for its deepest deployment in the PhilippineSea experiment. (b) The measured sound speed profiles from the descent and ascent.


0.43 m, with a depth rating of 11 km,significantly greater than that of its pre-decessors. This improved depth capa-bility, along with our independentpressure tests of the HTI 94 SSQhydrophones and the Novatech instru-ment housings to an equivalent depthof 12 km, will give Deep SoundMk. III a full ocean depth capability.Other modifications will include theaddition of high-precision, very-lowdrift tri-axial accelerometers, whichwill be used for inertial navigation ofthe system. The intention is to providea current-profiling capability by moni-toring the motion of the platform dueto advection by local currents duringits descent and ascent through thewater column.

AcknowledgmentsThe authors wish to acknowledge

Kevin Hardy of Deep Sea Power &Light for his invaluable assistancewith the deve lopment of DeepSound. The willing efforts of the cap-tain and crew of the R/VKiloMoana toensure the safe deployment and recov-ery of Deep Sound Mk. I during thePhilippine Sea experiment are greatlyappreciated, as is the enthusiastic assis-tance of the North Pacific AcousticLaboratory scientists during the re-search cruise. The research programon Deep Sound was supported byDrs. Ellen Livingston and RobertHeadrick, Ocean Acoustics Code, theOffice of Naval Research, under grantnumber N00014-07-1-0109.

Lead Author:Michael J. BuckinghamMarine Physical Laboratory,Scripps Institution of OceanographyUniversity of California, San Diego9500 Gilman Drive, La Jolla,CA 92093-0238, USA

Email: [email protected];http://extreme.ucsd.edu

ReferencesEwing, M., Worzel, J. L. 1948. Long-range

sound transmission. Geol. Soc. Am. Mem.

27:1–35.

Gaul, R.D., Knobles, D. P., Shooter, J. A.,

Wittenborn, A. F. 2007. Ambient noise

analysis of deep-ocean measurements in the

Northeast Pacific. IEEE J. Oceanic Eng.

32(2):497–512.

Morris, G.B. 1978. Depth dependence of

ambient noise in the northeastern Pacific

Ocean. J. Acoust. Soc. Am. 64(2):581–90.

Munk, W.H., Worcester, P., Wunsch, C.

1995. Ocean Acoustic Tomography. Cam-

bridge: Cambridge University Press.

Wenz, G.M. 1962. Acoustic ambient noise in

the ocean: spectra and sources. J. Acoust. Soc.

Am. 34(12):1936–56.

Weston, D.E. 1980. Ambient noise depth-

dependence models and their relation to low-

frequency attenuation. J. Acoust. Soc. Am.

67(2):530–37.


P A P E R

HADEEP: Free-Falling Landersto the Deepest Places on EarthA U T H O R SAlan J. JamiesonToyonobu FujiiMartin SolanImants G. PriedeOceanlab, University of Aberdeen

A B S T R A C TThe hadal zone, comprising mostly deep trenches that plummet to nearly

11 km deep, represents the largest poorly understood habitat on Earth. This knowl-edge dearth has been technology induced rather than of scientific interest. TheU.K.–Japan collaborative project Hadal Environment and Educational Program(HADEEP) is one venture where scientists and technologists have been workingto fill this knowledge gap, particularly from a biological perspective. With limitedfunds and even more limited time, two 12,000-m autonomous free-fall baited im-aging landers, known as hadal landers, were constructed to follow in the footstepsof the 1960 Trieste I dive; “to remotely go where two guys had gone before.” In thepast 2 years, the hadal landers have been deployed in five hadal trenches in theNorth and South Pacific Ocean across a depth range of 5,500–10,000 m. Thisnew technology has led to many new discoveries including, among others, largeaggregations of fish at 7,703 m, which are the deepest video footage of fish evertaken. Here we describe the origins of the HADEEP project, the challenges in devel-oping the technology, and the scientific outcomes of exploring the deepest environ-ment on Earth some 50 years after the pioneering Trieste I dive to Challenger Deep.Keywords: Hadal zone, Trenches, Free-fall baited landers, Deep-sea technology

Introduction

The hadal zone (6,000–11,000 m)is a geographically disjunct deep-seaenvironment comprised mostly ofdeep trenches formed by tectonic sub-duction (Stern, 2002). Hadal trenchesaccount for the deepest 45% of theoceanic depth range and host activeand diverse biological communities(Beliaev, 1989). The first major trenchsampling campaigns were conductedduring the early 1950s on the DanishGalathea and Russian Vitjaz expedi-tions. Using trawl and grab methods,the diversity, abundance, and biomassof invertebrates were described andshowed a seemingly high degree of en-demism. Since then, very few trenchsampling campaigns, particularly atan intertrench level, have been under-taken and as a result ecological infor-mation is sparse. All reviews of thehadal environment (Wolff, 1960,1970; Angel, 1982) have primarilybeen based on the two 1950s datasets; therefore, ecological interpreta-tion of hadal trench ecosystems is notcomprehensive and is at best specula-tive. Considering all trenches to be asingle habitat is likely to confuse inter-pretation of environmental drivers. In-tertrench ecosystems are likely to bedetermined by the interaction of, for

example, the geography, hydrology,food supply, topography, seismic ac-tivity, substrata, hydrostatic pressure,and temperature.

The biology and the ecology athadal depths are perhaps no morecomplicated than at shallower depths.This knowledge gap is a result of insuf-ficient technology and therefore accessto this environment. Renewed interestin these deep trenches combined withmodern technological advances hascreated new opportunities to exploreand understand the deepest environ-ment on earth.

Among other new international ef-forts, one such project is currently ad-dressing this knowledge gap andproviding a more detailed insight intolife in the trenches: the Hadal Envi-ronment and Educational Program(HADEEP). HADEEP is funded

jointly by the National EnvironmentalResearch Council (NERC, U.K.) andthe Nippon Foundation (Japan) as acollaborative project between theOceanlab, the University of Aberdeen(U.K.), and the Ocean ResearchInstitute (ORI), University of Tokyo(Japan).

Conceiving HADEEPThe HADEEP project was con-

ceived during in impromptu trip to abar in Aberdeen town centre duringthe Benthic Dynamics conference(March 25–29, 2002). The conferencewas comprised mostly of participantsinvolved in Sediment Profile Imaging(SPI) cameras. Among those presentwere Martin Solan, a benthic ecolo-gist, and Alan Jamieson, an engineerfrom Oceanlab. A few beers later, the


conversation turned to “who has takenthe deepest SPI image?” The awardwent to a brave SPI enthusiast fromVirginia who had taken an image at6,000 m despite his camera only be-ing rated to 5,000 m (Diaz, 2004).Several beers later, the conversationmeandered into how that could bebeaten, which eventually led to whereit could not be beaten. That placeof course was Challenger Deep in theMarianas Trench (∼11,000 m). Al-though the details are now perhaps abit fuzzy, the night ended with a confi-dent “let’s go to the Marianas Trench.”

At that time, the Japan Agency forMarine-Earth Science and Technology(JAMSTEC) were successfully operat-ing a 12,000-m rated remotely operatedvehicle (ROV) called Kaiko (Takagawa,1995; Mikagawa and Fukui, 1999).The next day at the conference, mem-bers of JAMSTEC who were also at-tending were approached by two guysfrom Aberdeen with an enquiry to de-ploy a mini-SPI camera on Kaiko.

Developingthe Hadal-Cam

The following year saw efforts inboth Japan and the U.K. to securefunding to develop the technology re-quired for hadal rated instrumenta-tion. The original idea was to designa camera system capable of both SPIimaging and seafloor imaging. Thisalso coincided with a part-time PhDstudy developing autonomous instru-mentation platforms for deep-sea bio-logical studies ( Jamieson, 2004). Aspart of that PhD, pressure vessel andoptical viewports were theoretically de-signed and prototypes were tested towithstand pressures of 1,400 bar(11,000 m operational depth with3,000 m safety factor). A sum ofmoney was eventually secured from in-

ternal Aberdeen University funds todevelop a 12,000-m rated videocamera that became known as theHadal-Cam. Although the Hadal-Cam was only one piece of a poten-tially larger project, it provided anasset in which to secure a larger sup-porting grant to use the Kaiko ROV.The money for deve loping theHadal-Cam was awarded on May 19,2003. Elsewhere on May 19, 2003,the Kaiko ROV was tragically lost atsea while surfacing in an emergencyduring a typhoon (Momma et al.,2004), an unprecedented loss todeep-sea exploration. Meanwhile, itwas decided to continue developingthe Hadal-Cam. Knowing that anyvideo footage would be of public inter-est it was important to source a camera“better than TV” quality. A HitachiHV-D30, 3CCD color video camerawas chosen (800 TV lines) with a2.8- to 8-mm wide-angle varifocallens. The system was designed to oper-ate autonomously, and video capturewas controlled by mission control soft-ware, specially developed by JohnKinmond at NETmc Marine (U.K.).

The software permits user definedpower up/down sequences, repeti-tions, and start delay. A relay board,with built in microprocessor, wasused as the interface between the cam-era, lights, and recorder and enabledthe recorder to power off and on tomaximize battery life. The recorderwas a modified NETmc Marine DVRInspector, a high-end broadcast qualityMPEG2 recorder with an Opti-baseencoder card (type MPG9005). Thisgave a screen resolution of 704 ×576 pixels. Illumination was providedby twin 50-W lamps, and the entiresystem was powered by a 12-V leadacid battery (SeaBattery; Deep SeaPower & Light, USA). The cameraand lights required in-house customiz-

ing to withstand the enormous pres-sures at hadal depths. The pressure-resistant housings designed by Jamieson(2004) were based on the elementarymechanics of Roark’s Formula for Stressand Strain (Young, 1989) and prior ex-perience of designing for 6,000 m. Tolighten the payload weight of the ROV(or other potential vehicles), titanium6Al-4V provided the best strength-to-weight ratio and corrosive properties.While the main body of the housingwas relatively straightforward, thecamera window or “viewport” becamethe most challenging development. Itwas apparent that the problem oftransparent viewports at high pressurewas not a new one, even the crew of theTrieste I dive noticed a 2-mm creep oftheir viewports (Lt. DonWalsh, 2004,personal communication). Based onprinciples described by Gilchrist andMacDonald (1980), a series of acrylicbeveled disc test pieces were pressur-ized to 1,400 bar. On each cycle, theacrylic crept into the air cavity behindit. The distortion increased with timeat pressure, eventually resulting in theentire viewport being squeezed intothe housing, that is, baroplastic defor-mation (see Gonzalez-Leon et al.,2003). No noticeable deformationtook place until beyond approximately800 bar (8,000 m). After a series ofpressure tests at the Scottish OffshoreMaterial Centre at the University ofAberdeen, acrylic viewports were aban-doned on the grounds of baroplastic-ity. Further research into materials,viewport shape, and seating designwere investigated, and decisions weremade with the limited budget inmind. To keep costs low, a plane discwindow design was favored as they re-quired less machining, less wasted ma-terial, and therefore reduced costs.With acrylic eliminated from thestudy, borosilicate glass and sapphire


discs were tested. Sapphire offered thebest solution in terms of size and reli-ability, whereas borosilicate windowswere unpredictable and become dis-proportionately large. So much so,the equivalent thickness of a planedisc window in sapphire is less thanhalf that of borosilicate (Figure 1)

and furthermore did not incur any sig-nificant cost increase. The free diame-ter, that is, the hole that the cameralens protrudes through the housingend cap, was just 30 mm; therefore, asapphire disc of 60 mm diameter by15 mm thick, seated on a 5-mm2 axialquad-ring (40mm inner diameter) suf-ficed. This relatively small and cheapsolution was then successfully testedto 1,400 bar for up to 24 h.

With the lamp housings, a differentsolution presented itself. A chance en-counter with Gerald Abich at NautilusMarine Services (Bremen, Germany)led to an idea of using two Vitrovex®glass mini-spheres (100 mm inner di-ameter). These spheres were design tobe small and just coincidentally couldhold 1,200-bar pressure. As the opticalpath of the illumination is not as criti-cal as the camera, the mini-spheresprovided another very simple and

cost-effective solution. In the end, the12,000-m rated 50-W lamps cost lessthan o f f - the - she l f commerc i a l50-W lights rated to 6,000 m.

At this point, the Hadal-Cam wasnot completed as the spiraling costsof titanium had put Ti 6Al-4V beyondthe financial limits of the project. So by

the end of 2004, all that was achievedwas a PhD thesis, two lamps, a sap-phire window, the guts of a camera, abag of deformed acrylic, and a big idea.Following several unsuccessful at-tempts to secure funding, it seemedthat determination and delusions ofgrandeur alone were not enough.

The HADEEPProject Origins

During 2006, negotiations withour Japanese collaborator, who bythen had moved from JAMSTEC tothe Ocean Research Institute, Univer-sity of Tokyo, had opened a dialoguewith the Nippon Foundation (Japan).The Nippon Foundation liked theidea and agreed to fund a joint projectto investigate life in the hadal trenches.The complication was that althoughthey would support access to research

vessels, there was not enough moneyto actually construct a hadal rated vehi-cle and there were still no signs of aKaiko ROV replacement. However,things started to fall into place fromhereon. Oceanlab, founded by Prof.Monty Priede had been built around a20-year history in constructing baitedlanders (autonomous free-fall vehicles)used to image deep-sea fauna. Withsome consideration of deep-sea ecologyand optimal foraging theory, the re-moteness from surface derived particu-late organic matter should result inanimals relying more on carrion falls(dead fish and cetacean carcasses) thatshould reach the seafloor irrespective ofdepth. It then seemed logical to extendthis deep-sea baited lander expertise tofull ocean depths and not go down themini-SPI route as originally planned. Agrant application entitled “HADEEP—Life at extreme depth; benthic fishes andscavenging fauna of the Abyssal toHadal boundary” was submitted to theNERC (U.K.) and was successful. Theapplication proposed the constructionof two hadal rated baited landers and afull-time Postdoctoral Research Fellow.The landers would be a baited videoand a baited stills lander. The still imag-ing technique provides a time course ofscavenging fauna to estimate populationsize whereas the video system wouldprovide behavioral and physiologicaldata of the observed fauna. Aroundthat time, an opportunity of a researchcruise was offered by Prof. Hans-JochenWagner of the University of Tubingen,Germany, who had secured a 3-weekexpedition between Samoa and NewZealand on the German research vesselSonne. Although the cruise was primar-ily mid-water trawling, the cruise pathjust so happened to transect the Tongaand Kermadec Trenches in the SWPa-cific, both of which are deeper than10,000 m. The cruise left from Samoa

FIGURE 1

A comparison of window thickness against failure pressure of borosilicate glass (left) and sapphire(right) of varying window free diameters. The equivalent window in sapphire is less than half thethickness of borosilicate.


on the 1st of July but the funds fromNERC were not received until the 1st

of February. The shipping time toSamoa was “at least 2 months” leavingjust 3 months to design, construct,test, and mobilize the landers fromScotland to New Zealand.

The Hadal LandersAutonomous landers are comprised

of two parts: The delivery system(buoyancy, ballast, structure, andacoustic releases) and the scientificpayload (cameras and environmentalsensors). The basic delivery system car-ries and protects the scientific payloadwithin a frame. Buoyancy is coupledto the topside while ballast is coupledto the underside and temporarily heldby the acoustic releases. With the bal-last on, the lander free falls to the seabedwhere the autonomous instrumenta-tion perform preprogrammed tasks.By acoustic command from the ship,the releases jettison the ballast weightsand the ascension to the surface beginsby virtue of the positive buoyancywhere it is retrieved by the surface vessel(for further details on lander design seeTengberg et al., 1995; Bagley et al.,2005).

The Delivery SystemThe structure of the landers were

based on existing Oceanlab video tri-pod landers (for, e.g., Priede et al.,2006) made from marine grade alumi-num 5082 but re designed to 3/4 thesize. The buoyancy was tethered inoff-line modules on a mooring lineabove the frame. This method permitsthe landers to be deployed from rela-tively small ships and can be modified/replaced depending on how the landerevolves. A 45-kg clump of ballastweights were suspended from each ofthe three legs approximately 250 mm

from the seafloor to give a confidentdrop when triggered. The biggest chal-lenges in the delivery system were sourc-ing the 12,000-m rated acoustic releasesand buoyancy.

For over 10 years, Oceanlab hadbeen using IXSEA acoustic releases,formally MORS and OCEANO.IXSEAwere approached about extend-ing their product depth range to12,000 m. The acoustic releases are akey component in lander operationsand thankfully IXSEA did not quitefall off their chair when asked. Onthe contrary, a couple of monthslater, four “ultimate depth” 2500-tiacoustic releases arrived in Aberdeen.Two releases were incorporated intoeach lander, simultaneously coupledto a ballast release catch to provide

back-up in the unlikely event oneshould fail. The releases comprisedthe standard electronic sub-assemblyof the Oceano 2500 Acoustic Releaserange, rehoused in a titanium grade5 body tested to 1,420 bar. In good en-vironmental conditions, the acousticperformance allow ranges >12,000 m.The remote communications wereprovided by the standard TT801Deck Unit.

There were a few avenues toexplore in sourcing the buoyancy: syn-tactic foam, ceramic spheres, titanium

spheres, and glass spheres. The syntac-tic foam option was unavailable partlydue to time constraint and partly dueto costs. The ceramic spheres were in-vestigated but that technology at thetime was in its infancy and was felt tobe too high risk in this application. In-terestingly, titanium spheres will notproduce significant positive buoyancyat 12,000 m. For example, assuminga design safety factor of 1,400 bar fail-ure pressure, the positive buoyancygenerated by any diameter of spherewill be less than 2.5 kg due to the re-quire wall thickness (essentiallyweight) required to withstand the am-bient pressure (Figure 2). Again, asluck would have it, Nautilus MarineServices in Germany, who had previ-ously supplied the mini-spheres, ap-

peared confident they could increasethe wall thickness of their standard17-inch Vitrovex® sphere for 12,000 moperations. The spheres had an outerdiameter of 432 mm and an inner di-ameter of 393 mm (20 mm wall thick-ness) producing 19 kg of positivebuoyancy each. The catch was thatthey would not be ready in time forthe U.K. to Samoa shipment and there-fore had to be shipped directly fromGermany to Samoa.

One other component to the deliv-ery system is the location aiding

FIGURE 2

The required wall thickness (mm) and resulting positive buoyancy (kg) of titanium and borosil-icate spheres of varying inner diameter (100–500 mm) at 1,400-bar pressure. Titanium spherescannot produce significant positive buoyancy at these depths.


devices for when the landers surface.These are typically a strobe light, aVHF beacon, and a flag. The flag wasas standard (orange); however, a greatdeal of time was invested in redesign-ing the VHF radio and Xenon strobe(Novatech RF-700A and ST-400A, re-spectively; Cobham Ltd, Canada).These required rehousing into aNautilus12,000-m glass sphere as they are sup-plied as 7,300 m rated. Roger Scrivensat RS Aqua (U.K. agents for bothCobham and Nautilus) randomly sug-gested sending one of these housings toNautilus to pressure test it as he had afeeling it was good to 1,000 bar. Somefurther calculations were done and sur-prisingly the standard off-the-shelf7,300 m rated Novatech radiosand strobes are capable of 10,000 moperations.

The Scientific PayloadThe old plans for the Hadal-Cam

housings were reviewed and with thecosts of titanium now increasing be-yond all reason they were reluctantly re-designed in Stainless Steel UNS32550.The electronics were housed inone large cylinder (later described as a“cannon-barrel”) and the camera washoused remotely in a smaller versionincorporating the sapphire viewport.The size of the electronics housingwas such that it weighed over 100 kgin air and would not fit into any pres-sure test vessel capable of 1,400 bar. Itwas therefore tested to 700 bar atOceanlab with the remaining fewthousand meters relying heavily oncrossed fingers and Roark’s formulas.The Hadal-Cam was positioned onthe landers lower deck 1 m off the sea-floor. The camera and lamps face ver-tically down and focused on a 10-mmdiameter × 1,000-mm bar where thebait is secured. This produced a field-of-view of 68 × 51 cm (0.35 m−2). The

bulkhead connectors and cabling werereadily available as standard Impulse20,000 psi rated wet pluggable se-ries (Teledyne Impulse, USA). Whenready to explore the deepest places onearth, it was essential that the depthwas recorded. Another chance encoun-ter, this time with Calvin Lwin fromSeaBird Electronics Ltd (USA) led tothe purchase of two SBE-39 temperatureand pressure sensors rated to 10,500 mwith an accuracy of 0.0002°C and0.1%, respectively.

The last item of scientific payloadto be sourced was the digital stillscamera. With the time constraints, itwould be difficult to design and buildone in-house. Oceanlab typically useKongsberg Maritime 6,000 m rateddigital stills cameras and so they wereapproached. Like Nautilus, Kongsberggratefully agreed to supply such acamera but again could not make theshipment to Samoa with the rest ofthe equipment; therefore, a third ship-ment was scheduled to rendezvous inSamoa. The camera was an OE14-2085-megapixel digital stills camera basedon Canon G5 technology. It had a re-mote flash gun and both were housedin grade 5 titanium. The camera andthe flash were powered by a 24-Vlead acid battery (SeaBattery; Deep-Sea Power and Light, USA).

In addition to the landers “high-tech scientific payload,” three baitedfunnel traps, made from garden wireand drainage pipe, were lashed to thefeet to collected any small scavengingcrustaceans for taxonomic and geneticstudies.

The landers were finally assembled,albeit still missing several crucial com-ponents, a few days before the ship-ment date, just in time for a quickdunk in a test tank before loading the20-foot container destined for Apia,Samoa (Figure 3).

Into the Hadal ZoneThe South Pacific

At the end of June, Drs. Jamiesonand Solan and the newly appointedDr. Toyonobu Fujii met the RVSonne in Apia. After a trying time get-ting the equipment cleared of customs,it became apparent that there may beproblems with the other shipments.The camera eventually arrived with2 days to spare. On the day of depar-ture, the ship was due to sail at0930 h. The thirty 17-inch glassspheres finally cleared customs ataround 0900 h and were hastily thrownon board in disbelief before transitingto the Kermadec Trench.When exactlythey arrived in Apia is still unknown.

The very first time the landers werecompletely assembled and testedminutes before the descent to 6,000 mon the edge of the Kermadec Trench.The landers were christened, ratherunimaginatively, Hadal-Lander A(video; i.e. Hadal-Cam) and Hadal-Lander B (stills). The Hadal-Camwas set to record 1 min of footageevery 5 min (1 min on, 4 min off ),120 times, and the stills camera wasset to 60-s intervals. Thankfully, bothlanders returned on command the fol-lowing morning. Over the next 2 days,

FIGURE 3

An almost complete Hadal-Lander A ready fortesting (left). The Hadal-Cam camera housingand sapphire window assembly (top right)and a 50-W lamp housed in a 114-mm diam-eter mini glass sphere.


the landers were deployed to 7,000and 8,000 m. Unfortunately, as a re-sult of a fault in the voltage regulation,the Hadal-Lander B stills camera failedto operate. However, Hadal-LanderA was an unprecedented success. The6,000- and the 7000-m deploymentscaptured both the deepest ever deca-pods (a family including prawns,crabs, and lobsters), on this occasionthe natantian prawn Benthesicymus cre-natus ( Jamieson et al., 2009a), andfilmed the endemic snail fish Notoli-paris kermadecensis alive for the firsttime ( Jamieson et al., 2009b). Thissnailfish has only ever been trawledonce in the early 1950s and the Hadal-Cam managed to capture extensivefootage of three individuals swimmingand feeding in their natural habitat.The landers were later deployed to9,000 and 10,000 m in the TongaTrench. Interestingly, the Tonga Trenchis apparently the resting place of the ra-dioisotope thermoelectric generatorfrom the aborted Apollo 13 mission(which supposedly contained ∼4 kgof plutonium). The 10,000-m deploy-ment (Figure 4) was a great milestone

in the project, proving after all theseyears the capability for full oceandepth observations. The video footage

from 8,000, 9,000, and 10,000 mshowed ever increasing numbers ofsmall amphipods (Crustaceans), al-most exclusively the endemic speciesHirondellea dubia. The baited funneltraps managed to capture thousandsof amphipod specimens for taxonomyand population genetic studies.

From an ecological perspective, thecruise was an enormous success andnot only gave an insight into whatcould be achieved and proved thateach of the components were capableof 10,000-m operations, which camea great relief to the HADEEP teamand the component suppliers alike.

The North PacificThe RV Sonn e r e t u rn ed to

Auckland, New Zealand, where thelanders were shipped to Japan for thenext wave of expeditions. BetweenOc-tober 2007 and March 2009, fourtrench expeditions were undertakenin the NW Pacific: two to the Japantrench (7,100 and 7,700 m) on theRV Hakuho-Maru, one to the Izu-Bonin Trench (8,100 and 9,300 m)on the RV Tansei-Maru, and one onthe RV Kairei to the edge of the Mari-anas Trench (5,500 m), which waslater declared a national monumentby former U.S. president George W.Bush in 2009. Over the course of thecruises, the landers were upgraded andimproved on several levels. Firstly, a2-L Niskin water bottle (Ocean TestEquipment Inc., USA) was added toeach system and were coupled to theballast release mechanism to collectbottom water for laboratory based ox-ygenmeasurements. Also, the environ-mental suite was upgraded withSBE19plus V2 CTD profilers ratedto 10,500 m (SeaBird Electronics,USA). The CTDs provide a tempera-ture, salinity, and pressure resolu-tion of 0.0001°C, 0.4 ppm, and

0.002%, respectively, from the sea sur-face to the trench floors and were set tosample every 10 s throughout the de-ployment. The invertebrate traps alsoreceived an upgrade. Dr. Fujii, deter-mined to trap “something bigger,” con-structed a “giant funnel trap” fromgarden wire and an old sewage pipe, aclassic mix of high techmeets low tech,but with amazing results.

The highlights of these cruises werethe deepest ever decapods (again;Jamieson et al., 2009a), the deepestever grenadier or “rat-tail” fish (Cory-phaenoides yaquinae, family Macrouri-dae), and the first ever live footage ofanother snailfish, this time Pseudoli-paris amblystomopsis (family Liparidae;Jamieson et al., 2009b). Perhaps themost significant single deployment ofthe project was with Hadal-Lander Aat 7,703 m in the Japan Trench in Oc-tober 2008 when a total of 20 snailfishwere seen in view of the camera. Thiswas the deepest footage of fish evertaken and of so many it was truly re-markable. Furthermore, Dr. Fujii’sgiant trap captured not only three juve-nile snailfish, but two five giant amphi-pods of two species and two gastropods(Figure 5).FIGURE 4

The deployment and recovery of Hadal-LanderA to 10,000 m in the Tonga Trench from RVSonne in July 2007. FIGURE 5

High tech meets low tech: Hadal-Lander A withthe new CTD system pictured on the RV Tansei-Maru (left). The large and small funnel traps(top right) which caught the large amphipods(middle right) and the remains of the mackerelbait after 12 h on the trench floor (bottom right).


Due to adverse weather, ship timerestriction, and another unrelated elec-trical fault, Hadal-Lander B was onlysuccessfully operated in the 5,500-mMarianas Trench deployments.

At some point in the North Pacificexpeditions, the landers developednicknames: Hadal-Lander A becameknown asAlfie after a long story involv-ing a horse and Hadal-Lander B be-came known as Jonah after its ratherincredible run of bad luck.

Technical EvaluationAfter 15 deployments in five

trenches over 2 years, it is now possibleto technically evaluate the perfor-mance of the landers (Table 1).

The landers descended to thes eafloor a t a mean ve loc i t y o f45.6 m·min−1, which equates to3 h 27min to reach 10,000m. The av-erage ascent speed was 33.6 m·min−1,resulting in a 10,000-m ascent time of4 h 40 min. As the landers travelledthrough various water masses andchanges in density and pressure, thedescent slowed with depth and afterballast release slowed again duringascent, both by about 6 m·min−1 (Fig-ure 6). For practical reasons, a meanterminal velocity, as described byTengberg et al. (1995), is sufficientlyaccurate to plan experimental times.

One concern prior to hadal opera-tions was glass sphere fatigue undersuch immense pressure cycling. Todate, only one glass sphere out of 22regularly used spheres has been retireddue to excessive accumulation of glassdust on the inside but no failures atdepth have occurred.

The video camera was always setto record 1 min of footage every 5 min(1 min on, 4 min off ) 120 times. The1-min files in MPEG2 were 50.5 mega-bytes each, resulting in ∼6 gigabytes per

deployment. The average digital stillimage size was 1.6 megabyte resultingin ∼1.3 gigabyte of images per 12 h onthe seafloor.

The acoustic communicationswith the landers have been good.Two-way communication betweenthe releases and the deck unit via an 8-to a 16-kHz hull mounted transducer

on the Sonne provided extremely accu-rate slant ranges (within 100–200 m ofthe bottom depth). However, whenusing the over-the-side remote trans-ducer head, the return signal to ac-knowledge command execution is notdetected until the landers are ∼6,000–7,000 m deep depending on location.The release function always executed

TABLE 1

Specification summary of Hadal-Lander A and Hadal-Lander B.

Lander Hadal-lander A Hadal-Lander B

Type Baited Video, CTD Baited Stills, CTD

Nickname Alfie Jonah

Depth rating 12,000 m 12,000 m

Delivery system

Acoustic releases Oceano 2500-Ti UD (x2) Oceano 2500-Ti UD (x2)

Buoyancy 17″ glass spheres (x13) 17″ glass spheres (x9)

Total positive buoyancy 247 kg 171 kg

Ballast weight (wet) 135 kg (45 × 3 kg) 135 kg (45 × 3 kg)

Vehicle weight 180 kg 110 kg

Total weight (descent) 68 kg −ve 74 kg −ve

Total weight (ascent) 67 kg +ve 61 kg +ve

Descent velocity 45.6 m·min−1 33.6 m·min−1

Ascent velocity 54.2 m·min−1 34.0 m·min−1

Scientific payload

Camera Hadal-Cam Kongsberg OE14-208

Camera resolution/format 704 × 576 pixels (MPEG2) 5 megapixel (JPEG)

Camera sample interval 1 min every 5 min 1 min

Camera sample number 120 2000

Battery 12v lead acid 24v lead acid

Camera field of view 68 × 51 cm (0.35 m−2) 63 × 47 cm (0.29 m−2)

CTD SBE19plus V2 SBE19plus V2

CTD resolution (S,T,P) 0.4 ppm, 1 × 10−4°C,0.002%

0.4 ppm, 1 × 10−4°C,0.002%

CTD sample interval 10 s 10 s

Water sampler 2-L Niskin 2-L Niskin

Funnel traps 30 cm Ø × 40 cm (×1) None

10 cm Ø × 30 cm (×2)

Bait ∼1 kg mackerel/tuna ∼1 kg mackerel/tuna


first time but the long delay in acknowl-edging this can be uncomforting.

Free-fall vehicles are prone to stick-ing on the seafloor if deployed on softsediment. Sinking was observed in theKermadec Trench at around 7,000 mand in particular the deepest Izu-BoninTrench deployments (9,300 m). There,the lander sunk approximately 15 cminto the sediment (as indicated by thebait arm in the field of view).However,due to sufficient positive buoyancy(post-ballast release) and perhapsaided by the perforated footpads, thelanders are sufficiently capable of risingout of soft sediments.

ConclusionOver these past 2 years, the hadal

landers have provided a great insightinto the biological community of thehadal zone (Figure 7). Every expedi-tion has revealed something new andunforeseen, such as extending theknown depth range of decapods, alarge and important crustacean taxa,by over 2,000 m. Likewise, the abyssalgrenadiers or “rat tails” are an extremelycommon family of deep-sea fish,which are now known to extend atleast 1,000 m deeper than previously

thought. The video footage of the twosnailfish has perhaps been the biggestsurprise. This new physiological andbehavioral information suggests thatdespite being endemic to >6,000 mthey are in fact not unlike their shallowwater counterparts ( Jamieson et al.,2009b). Furthermore, the Hadal-Camobservations of such a large aggregationat 7,700mhave highlighted the need forreappraising hadal fish communities.The historical trawl records indicate

that fish living in the trenches are merelyeking out an existence in extremely lownumbers. This misinterpretation is ap-parently caused by the difficulty intrawling at such great distances fromthe surface, the efficiency of which iseven hard to evaluate. The passive na-ture of a baited camera sitting idly onthe seafloor appears far better suited inthis application than, for example, trawl-ing, or ROVs.

The uses of deep submergence ve-hicles such as ROVs are paramountin hadal exploration and the mappingof habitat and infaunal/epifaunal com-munities but have in the past been un-successful in quantifying larger mobileanimals. The sighting of a fish at Chal-lenger Deep during the Trieste I divewas quickly claimed to be erroneous(Wolff, 1961), and the archives ofthe Kaiko ROV do not contain anynoteworthy records of significantlymobile fauna. One tantalizing discov-ery made within HADEEP was thatthe species composition and behavioralobservations of fish beyond 7,000where uncannily similar to those de-scribed by J.M. Pérès in the ArchimedeBathyscaph in 1964 (Pérès, 1965).Very specific details relating to, for ex-ample, swimming behaviour, distribu-tion, and colorings were almostidentical in both studies. Why this issurprising is because the HADEEP re-cords were from the Japan Trenchand the Archimede records wherefrom the Puerto-Rico Trench, some4,000 nautical miles apart in differentoceans. Unfortunately, Pérès did nottake any photographic records norhas anyone since, suggesting there is adiverse and active community inhabit-ing the Puerto-Rico Trench waiting tobe found.

Combining all these technologieswill pave the way to a better under-standing of the trench environment;

FIGURE 6

Free-fall hydrodynamics: The decent and as-cent speeds of Hadal-Lander A over 10,000 min the South Pacific. The lander slows down by∼6 m·min−1 during both descent and ascent.

FIGURE 7

Images from the hadal landers: (a–b) Still imagesof a decapod and a rat tail from Hadal-Lander Bfrom 5,500 m in the Marianas Trench. (c–d)The decapods Benthesicymus crenatus andAcanthephyra sp. from ∼7,000 m in theKermadec Trench. (e) Swarms of the amphi-pod Hirondellea dubia from 10,000 m in theTonga Trench. (f) The first and only live foot-age of the snailfish Notoliparis kermadecensisfrom 7,000m in the Kermadec Trench. (g) Thedeepest rat tail (Coryphaenoides yaquinae;Macrouridae) ever found, 7,100, JapanTrench. (h) The first live footage of the snail-fish Pseudoliparis amblystomopsis (Lipari-dae), 7,100 m, Japan Trench. (i) The deepestfish ever filmed alive, 7,703 m, Japan Trench(P. amblystomopsis).


for example, acoustic and photo map-ping with selective sampling for biologyand geology and in situ experimenta-tion combined with more passiveshort-term observations and long-termmonitoring of, for example hydrology,seasonality, food supply, etc.

Underwater technology aside, lab-oratory based technology has movedon a great deal since the last majormulti-trench sampling campaigns inthe 1950s. Phylogenetics and bio-chemical analyses of specimens, suchas those collected by the funnel traps(Figure 8), can now reveal evolution-

ary pathways and food web structuresboth of which are particularly interest-ing given the geographic isolation ofthe hadal trenches.

The HADEEP project has not onlyprovided the marine science commu-nity with new insights into life in thedeepest parts of the oceans but hasalso managed to grab the imaginationof the public. The publicity surround-ing the filming of fish deeper than everbefore became international news in

October 2008. It was covered by mostmajor news networks and newspapersaround the world resulting in publiclectures and exhibitions in national sci-ence museums and ended up in the topfive most watched videos on YouTube.com for a spell. The footage even foundits way into the in-car TV screens of theTokyo underground on the JR Chuo-Line and the JR Keihintohoku-Lineand was broadcast to five million com-muters per day for 2 days. A lot of thispublicity included details of the boththeGalathea and the Vitjaz expeditionsand the famous Trieste I dive to Chal-lenger Deep, which raised both the pro-file of hadal science and renewed theinterest of these achievements, hope-fully inspiring a new generation.

The next step technologically isto upgrade the landers further withacoustic current meters to monitortidal flow in the trenches and possiblyin situ oxygen measurements. Fundingis also being sought to upgrade theHadal-Cam with smaller electronicsand a higher resolution video camera.The next wave of expeditions will seethe introduction of 12,000-m ratedfish traps and sediment grabs currentlyin the design and construction phase.Scientifically, the project will continueaiming to achieve as many deploy-ments in as many trenches as possibleto build an extensive archive on whichto draw inter- and intratrench com-parisons to provide a better under-standing of trench ecology and justwhat is going on in the deepest placeson Earth.

Although the NERC-funded com-ponent of HADEEP recently came toan end, the Nippon Foundation sup-port continues until 2011. Althoughfurther funding is being sought to ex-pand the scientific, technological, andexpedition elements, the project is stillvery much in full swing. Between Oc-

tober 2009 and June 2010, both thehadal landers will be deployed in theKermadec and Tonga Trenches withhelp from the National Institute ofWater and Atmospheric Research(NIWA) in New Zealand. The landersAlfie and Jonah will then be reunitedwith the RV Sonne for an expeditionto the Peru-Chile Trench in the fallof 2010 before, all going well, return-ing to Tokyo for a planned series of ex-peditions to the Japan and Izu-BoninTrenches in 2011.

As for autonomously following inthe footsteps of the Trieste I to Chal-lenger Deep, it was once said that“Alfie won’t sleep until ChallengerDeep.” This sentiment still stands.

AcknowledgmentsWe thank Dr. A.K. Matsumoto,

Dr. K. Kita-Tsukamoto, Prof. H.Tokuyama, and Prof. M. Nishida atthe Ocean Research Institute, Univer-sity of Tokyo, Japan, and crew andcompany of the Research VesselsSonne, Hakuho-Maru, Tansei-Maru,and Kairei. The HADEEP projectwas funded by the Natural Environ-mental Research Council (U.K.) andthe Nippon Foundation (Japan), withadditional support from the Universityof Aberdeen (U.K.)

ReferencesAngel, M.V. 1982. Ocean Trench Conserva-

tion. International Union for Conservation

of Nature and Natural Resources. Environ-

mentalist. 2:17.

Bagley, P.M., Priede, I.G., Jamieson, A.J.,

Bailey, D.M., Battle, E.G., Henriques, C.,

Kemp, K.M. 2005. Lander techniques for

deep ocean biological research. Underwater

Technol. 26(1):3–11.

Beliaev, G.M. 1989. Deep-sea ocean trenches

and their fauna. Nauka, Moscow. 244 pp.

FIGURE 8

Specimens from Hadal-Lander A funnel traps:(top row) scavenging amphipods from theJapan and Izu-Bonin Trenches, 7,000–9,300 m.(Middle row) A cumacean and a large amphipodfrom the Japan Trench 7,000–7,700 m. (Bottomrow) Gastropods and the snailfish Pseudoliparisamblystomopsis from 7,700 m in the JapanTrench.


Diaz, R.J. 2004. Biological and physical pro-

cesses structuring deep-sea surface sediments

in the Scotia and Weddell Seas, Antarctica.

Deep-Sea Res., Part 2. 51:1515–1532.

Gilchrist, I., MacDonald, A.G. 1980. Tech-

niques for experiments with deep-sea organ-

isms at high pressure. In: Experimental

Biology at Sea, eds. MacDonald, A.G., Priede,

I.G., 234–276, London: Academic Press.

Gonzalez-Leon, J.A., Acar, M.H., Ryu, S-W.,

Ruzette, A-V.J., Mayes, A.M. 2003. Low-

temperature processing of ‘baroplastics’ by

pressure-induced flow. Nature. 426:424–428.

Jamieson, A.J. 2004. Autonomous lander

technology for biological research at mid-

water, abyssal and hadal depths. PhD Thesis,

University of Aberdeen, U.K. 25 pp.

Jamieson, A.J., Fujii, T., Solan, M., Matsumoto,

A.K., Bagley, P.M., Priede, I.G. 2009a. First

findings of decapod crustacea in the hadal-zone.

Deep-Sea Res., Part 1.56:641–647.

Jamieson, A.J., Fujii, T., Solan, M., Matsumoto,

A.K., Bagley, P.M., Priede, I.G. 2009b. Liparid

and Macrourid fishes of the hadal zone: in situ

observations of activity and feeding behaviour.

Proc. R. Soc. Lond., B Biol. Sci. 276:

1037–1045.

Mikagawa, T., Fukui, T. 1999. 10,000-meter

class deep sea ROV ‘KAIKO’ and underwater

operations. In: Proceedings of the Interna-

tional Offshore and Polar Engineering Con-

ference, Vol. 2, pp. 388–394.

Momma, H., Watanabe, M., Hashimoto, K.,

Tashiro, S. 2004. Loss of the full ocean depth

ROV Kaiko: Part 1. ROV Kaiko—a review.

In: Proceedings of the International Offshore

and Polar Engineering Conference, Vol. 2,

pp. 191–193.

Pérès, J.M. 1965. Apercu sur les resultats de

deux plongees effectuees dans le ravin de

Puerto-Rico par le bathyscaph Archimède.

Deep Sea Res. 12:883–891.

Priede, I.G., Bagley, P.M., Way, S., Herring,

P.J., Partridge, J.C. 2006. Bioluminescence in

the deep sea: Free-fall lander observations in

the Atlantic Ocean off Cape Verde Deep-Sea

Res. Part 1. 53:1272–1283.

Stern, R.J. 2002. Subduction zones. Reviews

of Physics, 40(4):3-1–3-38.

Takagawa, S. 1995. Advanced technology

used in Shinkai 6500 and full ocean depth

ROV Kaiko. Mar. Technol. Soc. J. 29:15–25.

Tengberg, A.F. De Bovee, Hall, P., Berelson,

W., Chadwick, D., Crassous, P., Devol, A.,

Emerson, S., Gage, J., Glud, R., Graziottini,

F., Gundersen, J., Hammond, D., Helder,

W., Hinga, K., Holby, O., Jahnke, R.,

Khripounoff, A., Nuppenau, V., Pfannkuche,

O., Reimers, C., Rowe, G., Sahami, A., Sayles,

F., Schurter, M., Smallman, D., Wehrli, B.,

De Wilde, P. 1995. Benthic chamber and

profiling landers in oceanography—a review of

design, technical solutions and functioning.

Prog. Oceanogr. 35:253–294.

Wolff, T. 1960. The hadal community, an

introduction. Deep-Sea Res. 6:95–124.

Wolff, T. 1961. The deepest recorded fishes.

Nature. 190:283–284.

Wolff, T. 1970. The concept of the hadal or

ultra-abyssal fauna. Deep-Sea Res. 17:983–1003.

Young, W.C. 1989. Roark’s Formulas for

Stress and Strain, 6th edition, McGraw and

Hill, Columbus, Ohio.


P A P E R

Charting a Course for the Marianas TrenchMarine National MonumentA U T H O RMichael TosattoDeputy Regional AdministratorNOAA Fisheries Service,Pacific Islands Regional Office

Monument Overview

The Marianas Trench MarineNational Monument consists of ap-proximately 95,216 square miles ofsubmerged lands and waters of theMariana Archipelago. It will be man-aged in three units: the islands unit, thewaters and submerged lands of thethree northernmost Mariana Islands;the volcanic unit, the submerged landswithin 1 nautical mile of 21 desig-nated volcanic sites; and the trenchunit, the submerged lands extendingfrom the northern limit of the Ex-clusive Economic Zone of the UnitedStates in the Commonwealth of theNorthern Mariana Islands (CNMI)to the southern limit of the ExclusiveEconomic Zone of the United Statesin the Territory of Guam (Figure 1).No waters are included in the volcanicand trench units, and CNMI main-tains all authority for managing thethree islands within the islands unit(Farallon de Pajaros or Uracas, Maug,and Asuncion) above the mean lowwater line.

Objects of Scientific InterestIn January 2009, President George

W. Bush created this largest of marinereserves under the authority of theAntiquities Act of 1906, which protectsplaces of historic or scientific signifi-

cance. Only recently have scientistsvisited the realm of the monument,observing previously unknown bio-logical, chemical, and geological won-ders of nature.

The Marianas Trench is the deep-est point on Earth, deeper than theheight of Mount Everest above sealevel. It is five times longer than theGrand Canyon and includes some50,532,102 acres of virtually un-known characteristics.

The volcanic unit—an arc of un-dersea mud volcanoes and thermalvents—supports unusual life forms insome of the harshest conditions im-aginable. Here species survive in themidst of hydrothermal vents that pro-duce highly acidic and boiling water.

The Champagne vent, found at theNW Eifuku volcano, produces almostpure liquid carbon dioxide, one of onlytwo known sites in the world. A pool ofliquid sulfur at theDaikoku submarinevolcano is unique in all the world. Theonly other known location of moltensulfur is on Io, a moon of the planetof Jupiter.

In the islands unit, unique reef hab-itats support marine biological com-munities dependent on basalt rockfoundations, unlike those throughoutthe remainder of the Pacific. Thesereefs and waters are among the mostbiologically diverse in the WesternPacific and include the greatest diver-sity of seamount and hydrothermalvent life yet discovered. They also con-tain one of the most diverse collectionsof stony corals in the Western Pacific,including more than 300 species,

higher than any other U.S. reef area(Figure 2).

The Monument PlanningProcess

Presidential Proclamation 8335 es-tablished the Marianas Trench MarineNational Monument in January 2009and assigned management responsi-bility to the Secretary of the Interior,in consultation with the Secretary ofCommerce. The Interior Secretaryplaced theMarianas Trench and volca-nic units within the National WildlifeRefuge System and delegated his man-agement responsibility to the U.S.Fish and Wildlife Service. The Secre-tary of Commerce, through NOAA,has primary management responsibil-ity for fishery-related activities in thewaters of the islands unit.

NOAA and the Western PacificFishery Management Council are con-sidering how to manage sustenance,recreational, and traditional indige-nous fishing as sustainable activities.These activities will be folded intothe monument management plan.

The structure of the plan will besimilar to a National Wildlife RefugeSystem Comprehensive Conserva-tion Plan, which provides a 15-yearguide, using the best available scientificinformation, to help managers achievethe purposes stated in the Proclamationand the co-managing agencies’ mis-sions. The plan will outline a vision,goals, objectives, and managementstrategies for the Marianas TrenchMarine National Monument. It will


FIGURE 1

Nautical chart showing the extent of the three components of the Marianas Trench Marine National Monument: trench unit, islands unit, and ventsunit.


be accompanied by an environmentalassessment describing the alternativesconsidered and their environmentaleffects.

The management plan will be flex-ible and a “living document.” It will bereviewed periodically to ensure that itsgoals, objectives, and implementa-tion strategies and timetables remainappropriate.

You may find further informa-tion online at http://www.fws.gov/marianastrenchmarinemonument/,and <http://www.fws.gov/refuges/whm/pdfs/MTMNM_brief.pdf>.

FIGURE 2

Satellite-derived bathymetry of the Mariana Arcregion is shown in this computer-enhancedimage. EM300MultiBeam bathymetry collectedduring the Pacific Ring of Fire 2004 Expeditionis overlaid on the satellite data. Image cour-tesy of Dr. Robert Embley, NOAA PMEL, ChiefScientist.


C O M M E N T A R Y

The Old Arguments of Manned VersusUnmanned Systems Are About toBecome Irrelevant: New TechnologiesAre Game ChangersA U T H O RGraham HawkesHawkes Ocean Technologies/DeepFlight Submersibles

Full ocean depth has always beenthe Holy Grail; a rite of passage to thefuture.

In fact, there have been many divesto the deepest ocean since the historicdive byDonWalsh and Jacques Piccardin the bathyscaph Trieste (Figure 1),including three dives with the Japaneseremotely operated vehicle (ROV)Kaiko,numerous unmanned free vehicle land-ers, and the most recent dives withWoods Hole’s fiber optic tethered hy-brid (ROV/autonomous underwatervehicles [AUV]) Nereus. Nearly half acentury after the Trieste dive, Nereusmade a transect, wall to wall, acrossthe trench, from a ship of opportunity,recovering samples along the way. TheNereus dive prompted Don Walsh tocomment that “Nereus just drove a

stake through the heart of any idea ofbuilding a manned submersible forfull ocean depth”—a typically pithycomment from Walsh and, right orwrong, signals a new debate.

As I see it, if man is to have anymeaningful role in the future of deepsubmergence (beyond record-breakingor individual exploration), to be cost-effective, manned craft will need tobe about 1/10th current costs—andvisibly safer, so that there is no effectiveresistance from that quarter. The costfactor alone requires a “disruptive,conceptual leap forward” and onethat cannot be achieved by any con-ceivable development from existing,classical, manned vehicles.

The Silicon Valley definition of dis-ruptive technologies—those non-linear,leap-ahead advances that wipe out theold and rewrite the future—are those in-ventions that step down market coststo 10% of previous levels. The authorwitnessed such an event; the extinctionof commercial manned submersibles forthe offshore oil and gas industry in theearly 1980s. At that time, offshore oilwork was conducted by either mannedsubmersibles or heavy saturation divingsystems (both at similarly high daily costsof approximately $50,000per day). Largecompanies, such as Vickers Ocean-ics, dominated the industry and oper-ated large fleets of submersible motherships, each supporting a single, largeworking-class manned submersible.

The introduction of atmosphericdiving suits (ADSs) (Figure 2) andROVs disrupted the settled order.Even though ADSs and ROVs wereinitially poorly adapted to the work,their operational costs were roughly1/10th that of conventional submers-ibles, and the systems were available ata moment’s notice, “Where, WhenAnd As Needed (WWAAN)” fromsmaller ‘ships of opportunity.’ It turnedout that it was primarily the freedomfrom being a ship owner that spawnedcompetition and drove down inter-vention response costs disruptively.

At the time, no one knew to callfledging ADS and ROVs “disruptivetechnologies.” Rather, they were calledmany things, usually derogatory. Thento everyone’s astonishment, the iconsof the industry, like Vickers Oceanics,vaporized overnight, killed off by theunrelenting daily burden of their mar-velous mother ships. The author al-ways thought it ironic that one of the

FIGURE 1

Bathyscaph Trieste commences a deep dive.(Photo: U.S. Navy, courtesy John Michel).

FIGURE 2

Nuytco’s experimental exosuit swimming ADS.


last niches left for manned submers-ibles was science, the one user groupclaiming poverty.

The lesson I learned from theNorthSea was that there would be no compet-itive future for any diving system if, byweight, volume, or other need, it wouldbe so dependent on surface ships as toeffectively tie its operation to a dedi-cated mothership. As I saw it, to elimi-nate the mothership and to get toWWAAN meant that all up vehicleweight (for launch and recovery) shouldnot exceed 10,000 lb. Thus, I set a 5-tonlimit for our submersibles based on thegeneral availability and the launch/recovery capability of ships for hire.

So for manned craft to be compet-itive for the long-term future and toserve science as well as industry, the re-quirements I saw would be the abilityto accommodate a crew of two, withhover and work capability, all under10,000 lb (Figure 3). In addition,while we’re at it, it seemed a good ideato eliminate the depth question. So thesubs should be rated to 37,000 feet, withminimum 1.5 safety factor (structuralstrength to 56,000 feet). This was atough challenge that could not be metby further development of existingdeep subs. Hence, a fresh start and ex-perimental approach was needed. I “re-tired” from industry, where sales of

manned craft had tailed off anyway,and built a skunk works, HawkesOceanTechnologies (HOT), anddevel-oped a long-term experimental attitude.

We knew the fundamentals of pack-aging two humans in the ideal spheredrove displacement/weight too high.For example, our lightweight, spherical,acrylic pressure hulled, two-personDeep Rovers weighed over 12,000 lb,and conventional subs that are closerin depth rating to our full ocean depthgoals weighed in at about 50,000 lb.This told me that a spherical pressurehull accommodating two in reason-able comfort, no matter how attractivefrom a structural point of view, was anon-starter.

So to get weight down to less thanone-quarter that of conventional sub-mersibles and be comfortable, thekind of anthropomorphic, form-fittingpressure suits of the ADS, rather thantraditional spheres, was closer to theanswer. Again from early studies, thelowest practical displacement for2,000- to 3,000-feet ADS “pressuresuits” is about 2,000 lb (2,500 lb morerealistic). In the 1970s, the best com-promise adopted was the “Mantis”-type pressure hull—a cylindrical form(next best to sphere, but a distant sec-ond), with crew prone. We came tothink of this hull form as a “pressurepod.” In the late 1980s, HOT usedthis configuration for our first proto-type, DeepFlight I, which we launchedin 1995 (Figure 4).

We took a giant leap forward in2005 when the late adventurer, SteveFossett, commissioned HOT to builda 37,000-foot vehicle, DeepFlightChallenger (Figure 5). We were notable to discuss the project during itsdevelopment, but I can now tell youthat indeed we designed and built a37,000-foot submersible, and all pres-sure and active components (thrusters,

lithium batteries, control actuators,weight drop, lights, buoyancy, sen-sors, etc.) were functionally pressuretested to 16,000–20,000 psi in a DoDfacility.

There were two problem areas:First, and as Jerry Stachiw predicted,modern development of carbon fiberresins had not solved the “unexplained”loss in compressive strength of massivecarbon fiber at extreme compressiveload. This surprised both the knowl-edgeable carbon manufacturer as wellas myself. In order to test to failure,we had several 1/3-scale pressure hullsbuilt, each with variations from theintended design in order to cause failurewithin the available test range. Typically,the model hulls predicted to fail at13,000 psi would fail at 11,000 psi—a significant loss. After minor improve-ments over a 12-month developmentperiod, the final pressure hull de-sign was modified to use the lower,

FIGURE 3

DeepFlight II concept “work class” vehicle.

FIGURE 4

First prototype winged submersible,DeepFlight Iwith form-fitting pressure hull.

FIGURE 5

DeepFlight Challenger and HOT Team.


allowable maximum stress as indicatedby the model testing (Figures 6 and 7).

The second problem area was thefailure of the expensive glass dome(Figure 8), which we experienced onthe “final” testing of the fully assem-

bled pressure hull. This failure wasproven to be caused by mis-machinedor warped titanium seat rings. Theproblem was fixed in a few days, butthe submersible now needed a newglass dome and needed to be re-tested.Unfortunately, Steve Fossett perishedin a plane crash before we were ableto replace the glass.

Obviously exotic materials wereneeded for these new pressure podsand the work of Jerry Stachiw atNOSC led the way. Jerry was an activeconsultant for theDeepFlight Challengerdesign and build and was greatly missedwhen he passed away.

Well aware we needed to designto be competitive against future un-manned systems, and with camerasevolving faster than human eyes, thismeant that view ports were also non-starters. (I always hated them anyway.)So all pressure pod alternatives we de-veloped included full-view, hemi-spherical, clear domes (Figures 8 and9). Adding personnel would obviouslyinvolve a second accommodation pod,so the whole concept became verymodular, and many advantages accruefrom such modularity.

Such low-volume pressure hullscould be built to be extremely com-fortable, even soothing, but they arebest thought of as “pods” rather than“hotel” accommodations. Therefore,mission times needed to be 4–6 hoursmaximum. Follow that reasoning, de-

scent and ascent times ideally neededto be kept to 1 hour. Hence, for fullocean depth, vertical descent speedneeded to be something like 7 mph. Ig-nore over-inflated speed numbers for ex-isting subs, add fudge factors, anddescent speed is almost an order of mag-nitude higher than current rates. Followthe numbers for thrust (square of speed)and power (cube of speed) and, gulp,this is not your father’s submersible.

Not only does the drag/speed/power numbers put the design in a dif-ferent class, it can no longer just sink,maintaining fixed “sitting” attitudes inthe cabin. At those speeds, the nose ofthe craft’s attitude (nose up/down) hasto point where the vehicle needs togo—just as surely as does left/right tokeep the streamlined axis in line withthe intended direction of travel in threedimensions. This is quite different fromconventional submersibles, which accesstwo dimensions, and are basically akinto underwater ballooning.

The craft then transitions from achambered nautilus, drifting up ordown with buoyancy changes, to a dol-phin. The best way to describe wherewe ended up is that we ran headlonginto the need to transition to full-onunderwater flight. Whether or not“underwater flight” is the right de-scriptor, it is the right concept sincethe math (adjusted for fluid mass) is al-most the same for similar mastery overthree dimensions in air or water.

Once we had the pressure hull ge-ometry, the materials, and the needfor underwater flight in the works,then the additional pieces of the puzzleseemed mundane: friendlier life supportmanagement systems, comfortable er-gonomics, lithium batteries, efficientthrust, electromechanical flight control/actuators, flight software/control, etc.,underwater flight instrumentation,ambient pressure composites, safer

FIGURE 6

Side view of the DeepFlight Challenger pres-sure hull.

FIGURE 7

Face viewofDeepFlight Challenger pressure hull.

FIGURE 8

Glass dome as originally built for DeepFlightChallenger.

FIGURE 9

Glass domes for DeepFlight Super Falcon.


buoyancy, etc.—all of which has beentested for the experimental DeepFlightChallenger to 16,000–20,000 psi.

Flight proved to have more valuethan at first understood. Efficient con-trol of large (lift) forces was obvious,but the simplicity and extraordinarysafety advantage of fixed buoyancywas not immediately obvious. Ulti-mately,HOT adopted aerospace think-ing and did not question the need forexperimental craft. It took five genera-tions (DeepFlight I, Wet Flight, Deep-Flight Aviator, DeepFlight Challenger,and DeepFlight Super Falcon) before ar-riving at Super Falcon—the first “nextgeneration” production craft. SuperFalcon was not imagined at the be-ginning of the DeepFlight program(1980s) and is the author’s favorite todate (Figure 10).

Of the five generations (six subs),three were full-on experimental craft(DeepFlight I, DeepFlight Aviator,DeepFlight Challenger), one was aone-off film project craft (Wet Flight),andDeepFlight Super Falcon (two builtin 2008–2009) were the first full pro-duction vehicles. We are now buildingthe next iteration of Super Falcon forprivate clients and have other produc-tion types in the works. Bear in mind,HOT was efficiently using experimen-tal craft, stripped of unnecessary bellsand whistles, to pioneer and prove thenext step. Such craft are bridges to the

future. If successful, they enable the fu-ture vehicles to then be relatively easilybuilt, adding back all the bells andwhistles needed.

However, relative to the early think-ing and “focus on full ocean depth,”DeepFlight Challenger has providedthe boost across the board to the HolyGrail. So even thoughDeepFlight Chal-lenger has yet to make the deep dive, ithas already completed full functionaltesting to 16,000–20,000 psi ambientpressure and is the bridge to our nextgeneration craft. Our new “work-type”8000-lb craft, with a safety factor of 1.5,has the same relationship to the “final”modular working solution long agopublished as DeepFlight II that Deep-Flight Aviator had to our next step, pro-duction version, DeepFlight SuperFalcon.

To HOT, the data and proof are inhand to build the idealized future work-ing submersibles—modular craft, withone or two crew, flyable (longer rangeand efficient survey, together with fullmid-water capability), with in-flightconversion to hover mode, and modu-lar work packages that would obvi-ously include manipulators, etc. Thesubs have ideal viewing for both pilotand passenger, and all weigh in under10,000 lb and are WWAAN capable.Depth on DeepFlight Challenger was37,000 feet with a safety factor of 1.5(current certification standards for ti-tanium), but new materials warranthigher margins. So the early depth limi-tation HOT sees for its first commer-cial “work” craft is about 27,000 feet.

Don Walsh and Jacques Piccardopened the pubic’s eyes to the possibil-ities for deep ocean exploration. Deep-Flight Challenger perhaps was the firstmanned craft scheduled to make a se-rious exploration of the ChallengerDeep post Trieste. The contract be-tween HOT and Steve Fossett was

that the craft would be built to winfor its owner (Fossett) the deepest solodive record and, for HOT, it was theproof of concept for full ocean depthworking vehicles.

For the author, both DeepFlightChallenger and Woods Hole’s Nereusare the harbingers of the future, withthe first prize going toNereus for a stun-ning success. The next descendantsfrom each will be wonderfully usableand cost-effective solutions. UnlikeAUVs and ROVs, which have verysharply defined capabilities, and arevery good at some tasks, and poor atothers, the descendants of Nereus andChallenger are the general solutionsneeded anytime work interventionand range are necessary. I say this be-cause work intervention eliminates theAUV, and range eliminates the ROV.

So what happens to the old mannedversus unmanned argument and whonow wins—given two good choices.Before trying to answer that, bear inmind that time changes more than thetechnology. When all this started, thecustomers for the sixty or so mannedcraft this author built were primarilyoffshore oil and gas, with a small sciencecomponent. The rate of build was ap-proximately five per year. In the inter-vening 15 years, the rate of sales fell tonear zero, with only a few sales anoma-lies: Deep Rover 1 for PhilNuytten andthe two classic Deep Rover 2s forFrench television. The sales rate stoodessentially at zero, or one submersibleevery five years.

With our breakthrough to ultra-light, flyable manned craft, HOT’ssales tentatively kicked in again andare now at the rate of 1 or more peryear and increasing. So the patient hasa pulse, is out of intensive care, andprospects are good. However, sales arenot to the old market. This is all new.Our early sales are now (skewed) to

FIGURE 10

The future of manned submersibles could bethe elegant DeepFlight Super Falcon.


early adopters—those who delight innew technologies and in pushingforward (i.e., venture capitalist TomPerkins), or those who need the newcapabilities (i.e., adventurer, SteveFossett), and those who see businessopportunity (Richard Branson). Lookat the names and you see a new day.James Cameron is widely rumored tobe headed into the deep and SylviaEarle is rumored to have deep pocketbacking for deep vehicles—all private,new money.

So getting back to the question,manned or unmanned—and this timewith different users, different markets—the question is most likely irrelevant.Manned versus unmanned was an ago-nized debate once upon a time whenonly sciencewas in the deep, andmannedsubs were horribly expensive. The nextgeneration users are more likely to havea clear need for manned craft or an ob-vious preference for remote vehicles.The AUV, ROV, AUV/ROV hybrid,and next generation-manned craft areall in it for the long haul (Figure 11).

FIGURE 11

A DeepFlight Super Falcon propels downwardinto the blue crystal waters of the Caribbean.


P A P E R

Project Deepsearch: An Innovative Solutionfor Accessing the OceansA U T H O R SLiz TaylorTony LawsonDOER Marine

A B S T R A C TThe year 2010marks the 50th anniversary of the first and only manned visit to the

deepest part of the sea. Over the past 50 years, even as technology has advancedwith breathtaking speed, there have been very few changes or advances in applyingnew technology to manned (human-occupied) vehicles for deep sea exploration.Today there are only a handful of deep research submersibles and all, with the excep-tion of the Chinese Harmony 7000, are aging assets. None are capable of exploring allareas of the ocean. Project Deepsearch is being undertaken by a small businessworking under the premise of a collaborative open source effort. Our goals are tobring innovative solutions to bear in five key areas of engineering and technologywhile engaging industry contributors and the public, enhancing awareness of theimportance of the oceans, marine science and education.Keywords: Glass, Lithium batteries, Ceramic flotation, Pressure testing, Dive profile

“What ’s your number”? It wasthe question posed time and timeagain over the past 17 years, to eachother, to staff members, to colleagues,to visitors—what would the cost befor building a manned submersiblecapable of providing full access(11,000 m) to the oceans? More im-portantly, what would the cost be fornot doing it?

It is said that we know more aboutthe surface of the moon than we doabout the deep ocean. People fly every-day 7 miles up in the sky. By 2008,there were 4,102 ascents to the sum-mit of Mt. Everest. Fifty years havenow elapsed since the first and onlymanned dive to the deepest point inthe sea. While some were content torely upon drones and robot technologyto explore the deep ocean, we werenot.

With every project completed, ourteam saw first-hand the need forgreater knowledge and better toolsfor ocean exploration. We read andre-read Busby (1969, reprinted 2006)and Stachiw (1990, 2003), weighingtheir arguments about the advantagesand disadvantages of materials andeven pros and cons of submersibles ingeneral. Peter Rona’s (2000) discus-sion on the importance of tooling, ma-nipulators, and the ability to collectsamples resonated with us as did his ar-

gument for the irreplaceable scientificvalue of human presence in the deepocean.

During the 5 year Sustainable SeasExpeditions (1997–2002), DOERwas engaged by Nuytco Research(www.nuytco.com) and NationalG e o g r a p h i c S o c i e t y ( w w w .nationalgeographic.com) to trainscientists, teachers, artists, and othersto operate small one-person DeepWorkers and Deep Rover submers-ibles working from many vessels ofopportunity.

We listened and learned from thescientists, what they liked and disliked.Most loved the simplicity of DeepWorker but wished for deeper capabil-ity. The single-person Deep Rovercould go a bit deeper, but havingbeen built in 1982, it was an agingasset. Beyond that, when thinking ofthe handful of deeper water vehiclesin particular, the wish was for longermission duration ( less transit /morework) and greater field of view. Allagreed with the axiom that “if a picture

is worth a thousand words, being thereis worth a thousand pictures.”

We kept track of some of theseassets, Alvin (4,500 m), Nautile(6,000 m), Mir I and II (6,000 m),and Shinkai (6,500 m), and realizedthat over the years, real innovationhad been slow in coming to deephuman occupied systems. Even thenew Chinese Harmony 7000 is verysimilar in appearance to what exists,although it is poised to become thedeepest diving manned submersible,surpassing Japan’s Shinkai by 500 m.

When the replacement Alvin de-sign was released, the moan was au-dible throughout the building alongwith a loud “Couldn’t the artist evenstep out on a limb!?” from the engi-neering offices. The answer, of course,was no. The artist could not and nei-ther could the scientists or engineersinvolved. Constrained by an existingmother ship, committees, and a myr-iad of other parameters set forth earlyon, innovation was not a consider-ation, budget was.


The DOER team did not have toworry about budget for Project Deep-search; there simply was not one, onlyideas and concepts percolating andgrowing. In 2003, an artist showedup at DOER. Filmmaker DavidRiordan stopped by to say that hewas for the first time in his life trulyafraid. Afraid of what was happeningto the oceans and what the conse-quences might be for people if some-thing was not done and soon. Hewanted to talk to our founder, SylviaEarle, about a report he had seen:90% of the big fish in the ocean weregone in the last 50 years. He was eagerto find a way to communicate theproblem to the general public. He lis-tened to Sylvia describe the need forimproved technology and basic un-derstanding and protection of broadocean systems, “our life support sys-tem,” she said. Sylvia continued, spell-ing out the importance of engagingthe public, providing knowledge, andhaving the capacity to care. He vowedto help her however he could. Thenhe listened to our wild ideas for ProjectDeepsearch: to develop and build a pairof innovative human-occupied sub-mersibles capable of providing scien-tific access to all parts of the oceanswhile engaging the public along theway.

Together, we pursued an inte-grated strategy for video games, socialnetworking, film, and books, the pro-ceeds of which we envisioned wouldfund the design and development ofProject Deepsearch. Artist RichardTaylor of Star Trek and EntertainmentArts fame worked with our engineersto develop concept art (Figure 1)while David worked with us on storylines, expedition possibilities, andmore. By then, we estimated thatthe number was $10–15 million persubmersible using a traditional steel

or titanium personnel sphere whilepushing for new, larger view ports.We speculated about the possibilitiesof advanced ceramics, grown sapphire,and glass.

A group of us went toWashington,D.C. to the National Geographicheadquarters to pitch the idea. Wedid not expect them to fund the proj-ect entirely but hoped they would col-laborate, provide some seed money, orat least lend their name to the effort.While they listened with interest, andpraised the vision, they could not finda fit within their existing programs(Walsh, 1990; Craven, 1990).

Moving forward, we pursued Proj-ect Deepsearch with limited resourcesand encouragement from ocean ex-ploration luminaries, including DonWalsh and John Craven. Drawingupon their papers and those of oth-ers in the special “Deepest OceanPresence” issue of the MTS Journal(1990), we identified many needsand many possible solutions. Wehoned to a science of the use ofstandardized ISO containers andequipment handling methods. This“mission module” philosophy allowsus to be self-contained with work-

shops, labs, and equipment, reducingmobilization/demobilization time andminimizing impact on the ships them-selves.We analyzed battery technologyresearch in conjunction with deep work-ers and a variety of multi-passengersubmersibles that passed throughour workshop.

Every ship we mobilized equip-ment on or off became an opportu-nity to further the operations plan forDeepsearch. We evaluated ships ofa l l kinds—refi t , purpose-bui l t ,SWATH, and single hull, moonpool equipped, those with A-frames,side launch, gantry cranes, internalmarina bays, heave compensated sys-tems, and more. The fact is thatdeep-water sites are not always con-ducive to over-the-side operations.Oceanic swell, wind, and other envi-ronmental factors reduce the opera-tional window. Thus, the launchand recover system must be able tosafely release, capture, secure, andhandle the crafts.

The ideal ship for such operationswould be one with Dynamic Posi-tioning level II or better, with a fullsuite of deep-water assets: autonomousunderwater vehicle (AUV) for broad

FIGURE 1

Original artist’s conceptual painting, 2003.


survey work, multi-beam for basicmapping, deep-water remotely oper-ated vehicle (ROV) for ground truthingand providing real-time video to the sur-face, and two deep-water submersibles.

More was learned during the de-velopment of DOER’s Morpheus, anadvanced long tunnel inspection sys-tem, and Tules, an integrated leveeevaluation system. Looking at aginginfrastructure and the aftermath ofhurricane Katrina, it became abun-dantly clear to us that lacking sufficientinformation, especially predictive in-formation, people could not makemeaningful or informed decisions.The same thing applied to the oceans.

It was around this time that SylviaEarle went to Spain to receive anInternational Geographical Societyaward. John Hanke, one of the prin-cipal developers of Keyhole MarkupLanguage, which became integral tothe development to Google Earth,was also an award recipient at theevent. Sylvia, in her speech, praisedGoogle Earth but went on to say itreally should be called Google Dirtsince they left out the oceans. Thiscomment led to meetings with Sylvia,John Hanke, DOER, David Riordan,and a small team from Google, in-cluding chief technology advocateMichael Jones and outreach specialistsRebecca Moore, Jenifer Austin, andSteve Miller.

Ideas bounced around and finallywhat emerged was a plan and templateto populate an ocean layer with bathy-metric data, stories, videos, and imagesfrom 10 “focus areas” to start with. Forthe next three years, DOER workedwith Google and the Navy via athree-way CRADA (cooperative re-search and development agreement)on bathymetric data sets and morethan 40 science advisors and hun-dreds of contributors to the effort.

The Ocean in Google Earth launchedwith the release of Earth 5.0 in Feb-ruary 2009.

Our work with development of the“ocean layer” required much by way ofnetworking and outreach to potentialcontributors. We did not limit our-selves to scientists but also contactedartists, film makers, photographers,U.S. and international governmentagencies, and yacht owners, manyof whom had “SeaKeeper” (www.seakeepers.org/technology.php) unitsaboard their ships collecting under-way oceanographic data. Some evenhad ROV or submersible footage tocontribute. Invariably the questionarose: why had we humans not donemore to explore the deep ocean? Whyhad we only once made a manned diveto the deepest point in the sea?

A Turning PointWe hosted many visitors and

workshops in conjunction with theproject and often shared our visionfor Project Deepsearch. One day, wehad such a meeting with a group ofVIPs and when asked, we elaboratedon the plan—six to nine months oftargeted research into five key areasof innovation to start with, followedby a course of testing, design, and de-velopment of prototypes and then thepush to build.

Two days later, we received a callconfirming a funding commitment toexplore the feasibility of developing afull ocean depth (FOD) human occu-pied submersible (HOV). The stipu-lations: make our research findingsopen source, seek out collaborators,innovate, publish, and make a differ-ence. Although the funding camethrough a foundation (www.deepdeep.org), the sponsor went further andactively engaged with the engineering

team, becoming personally involvedthrough meetings and a constantstream of e-mail, demonstrating theshared commitment to further knowl-edge about the oceans.

After clearing a number of projectsout the door, we commenced.

The Five Areasof Innovation

■ Platform/Submersible divingmechanism—dynamically con-trolled vs. buoyancy based

■ Personnel sphere—evaluate materials■ View ports—increase size■ Batteries—investigate technologies■ Flotation—ceramic spheres vs. syn-

tactic foam

Platform and GeneralDesign Goals

The oceans are a three-dimensionalenvironment. One of the most com-mon complaints from scientists is theamount of time spent in transit tothe working depth and the inabilityof most deep-water submersibles tostop, hover, and dive again for mid-water studies.

Existing deep-water research sub-mersibles generally have a similardive profile: they take on weight tosink to the desired depth, they shedweight once that depth is achieved,and they shed more weight to return,floating back to the surface. Thisstrategy has not changed much inmore than 50 years, and on everydive, with the exception of the Mir,the submersibles leave litter in theform of metal plate, shot, or sandbags.

The Deepsearch strategy is tomake the personnel sphere position-able for comfort and then to use acombination of thrust, movable trim


mass, and a variable buoyancy system(VBS) to pitch nose down, movingat up to 6 knots through the watercolumn to the working depth. Thisis achieved by changing the centerof gravity and by using power assist.The vehicle can stop at any pointalong the way to adjust buoyancy andattitude and can open the clear Perspexto extend lights, cameras, and manipu-lators for work before continuing thedive.

Minimizing the transit time andmaximizing the working time solveanother problem posed by scientists.Speaking with key science advisorssuch as Drs. Edith Widder, BruceRobison, Larry Madin, and PhilMcGillivary, we confirmed that theability to stop at any place along thedescent path and to then continuethe dive or to come part way up andthen descend again would be an in-credible breakthrough, especially ifcoupled with a large field of view.

In the case of Deepsearch, the var-iable mass will be the battery podsthemselves, which move up andforward for diving, center and downfor stability during the science missionand launch and recovery, then up andaft for ascent, leaving nothing behind.

Our basic design goals for eachsubmersible are:

Length: 11.3 m (37 feet)Beam - Operational: 3.44 m(11.3 feet)Beam – Shipping: 2.33 m (7.66 feet)Operating depth: 1,000m/11,000m(3,280 feet/36,089 feet)Normal Dive Duration: 10 hSpeeds:Cruising: 3.7 km/h (2 knots)Full: 11.1 km/h (6 knots)

Height: 2.31 m (7.58 feet)Draft: 2.31 m (7.58 feet) surfacedGross weight: 20 metric tons(44,093 pounds)

Payload: 680 kg (1,500 pounds)includes occupantsComplement:Pilot: 1Observers: 2

Pressure hull: 172.7 cm (68 inches),thickness TBD acrylic—1,000 m/172.7 cm (68 inches), 10.16 cm(4 inches) thick glass—11,000 mHa t c h op en i n g : 4 0 . 6 4 cm(16 inches), 39.37 cm (15.5 inches)maximum diameter for scienceequipmentTotal power: 2 ea. × 91 kWhper main propulsion batteries(260VDC × 350 Ah), Mission bat-tery is 91 kWh usable (260VDC ×350 Ah)Maximum cruising range (FOD):26 km (16 miles) submerged at3.7 km/h (62 m/min)Life support duration: 246 man-hours (10 h × 3 persons + 72 h ×3 persons)With this design (Figure 2), a sub

can reach FOD in approximately90 min. Lesser depths are obtainableat a scaled fraction of this time.New battery technology allows forthe power density to drive the sub-mersible for this period of time. How-ever, close consideration to drag isa prime objective in the design. Sixknots was a reasonable speed compro-

mise yielding relatively fast times todepth against a battery package thatmeets the weight goals of the design.

Streamlining for drag pushes backagainst the need for internal volumeto carry flotation and other systems.Several rounds of light computationalfluid dynamics (CFD) have beenundertaken to refine the basic shape(Figure 3). Rigorous CFD and towtank testing will need to be run to fi-nalize drag (and related propulsionpower requirements) and other dy-namic terms at speed to assure stabil-ity, that there are no control surfaceinversions, and that there is resistanceto de-stabilizing inputs. One advantageto a dynamically stable platform is thaton bottom, Deepsearch will always havea tendency to put its nose into currents.

While steel or titanium personnelspheres can withstand FOD pressures,there have been significant advancesin materials over the past 50 years.We investigated carbon fiber (Garvey,1990), ceramics (Yano, 2005), alu-mina (a metal/ceramic material), andtraditional materials. We consideredspheres, hemispheres, cylinder shapes,view ports, and viewing domes.We compared weights, compressivestrengths, tensile strength, and nu-merous other factors.

FIGURE 2

Conceptual rendering of Deepsearch sub-mersible, September 2009.

FIGURE 3

Deepsearch form evolution.


Personnel Sphere andView Ports

Paired with the personnel spherequestion was the view port question.Could we create a sphere, half alumina,or half glass? How would we seat thedissimilar materials? Where would thehatch be? How big could it be?

We were offered and took the op-portunity to examine the craft beingbuilt for the late adventurer SteveFossett. That vehicle had a full glass“nose cone,” which fractured duringpressure testing. The presumed failurewas in the seating of the glass to thetitanium ring. It was a sobering visit.

In our quest for larger view ports,perhaps even grown sapphire, we en-gaged with a number of glass expertsand made an exhaustive review of theworks of the late Dr. Jerry Stachiw(2003). While much work on glasshad been done by the Navy upthrough the 1970s, including a veryinnovative three glass sphere designby Will Forman (1999), it essentiallystopped there. The consensus for thiswas that technology did not exist atthe time that would allow the detailedmodeling and failure analysis tech-niques available today.

In due course, the path led to in-vestigation of a full glass personnelsphere (Figure 4), melding two areasof innovation into one big undertak-ing. Glass has been proven to with-stand great ocean depths as evidencedby the widely used “Benthos spheres”(www.benthos.com) and newerVitrovex spheres (www.nautilus-gmbh.de). The questions addressedfailure analysis, ease of manufacture,and practicality of mounting in theframework of the submers ib le .Today, this research is ongoing andcontinues to be extremely promising.If achievable, it will afford an un-

precedented view with a significantweight savings for the submersible asa whole.

With the realization that an all-glass man-sphere was more than apossibility, a push has been made tomove the sphere as far forward aspractical (Figure 5). Normally, thiswould have been rather simple, add-ing flotation high forward and abovethe sphere to offset the weight of thefront tool porch equipment. However,the desire to utilize the view affordedby the glass sphere has lead to the con-cept of a complete, 180° acrylic fairing,with a retractable lower half allowingtool porch use in situ. Additionally,Deepsearch has run out of room inheight and width with the desire tokeep the frontal cross section sufficientto fit in an ISO container. This re-

quires adding the floatation aft andcreating a counter moment by movingthe drive motors aft as well. The shapeand volume to achieve this are the low-est shape shown in Figure 3. This isnot as ideal from a drag or gross vehicleweight stand point but is still capableof obtaining the design goals.

Massive GlassGlass as a personnel sphere material

is at once intriguing and breathtaking.Despite years of successful deep-seaservice (Benthos and Vitrovex instru-ment housings), there is a natural res-ervation against using glass because ofits brittle nature. Yet when we think ofJapanese glass fishing floats washing upintact on a beach after a storm or thevenerable “message in a bottle” beingfound after years at sea, we realizethat glass is stronger than it appears.The virtues of unimpeded views arewell recognized: Deep Rover, DR1002,Johnson Sea Link, SeaMagine, Deep-See, and others have proven the con-cept with acrylic spheres.

Melding art and science together,we are investigating■ Ease of manufacture■ Composition and coatings■ Testing protocols■ Hatch and penetrators■ Reliability■ Mounting in frame

Working with world experts suchas Dr. Suresh Gulati and top manu-facturers Schott (www.us.schott.com)and Corning (www.corning.com),DOER is systematically addressingthese questions. Finite element mod-eling is being used extensively for allprocesses (Figure 6).

A revolutionary hatch concept hasbeen developed that completelychanges the approach to the glass inter-face. It avoids the high bearing stresses

FIGURE 4

Volume and form study of 68-inch ID glasspersonnel sphere.

FIGURE 5

Cutaway study of Deepsearch showing inter-nal assemblies.


experienced when a hemisphericalglass shell is joined to a metallic hull.All past attempts at massive glass forsubsea use have had problems in thisarea.

Test fixtures for seal material testinghave been built, and tests are in process.Results from these tests will yield consti-tuative relations for the design of ourseal. Trelleborg Sealing Solutions(www.tss.trelleborg.com) is collaborat-ing with DOER to develop a uniqueseal in parallel to our glass research efforts.

Fracture mechanics techniques arebeing used to quantify strength charac-teristics of porthole geometries, to eval-

uate different glass compositions, andasses the reliability of the structure.

Scale model spheres are being fabri-cated using Vitrovex flotation spheres.Pressure tests will determine seal inter-actions at the glass interface. Cycletesting of the scale models will be un-dertaken in a 24 inch cold isostaticpress (CIP) to FOD × 1.25 or existinghydrostatic test chambers to FOD.

Strategies for sphere retention willbe tested as well for shock loadingprotection, practical serviceability,and human factors.

To date, all research, modeling,and testing have yielded positive re-

sults; in most cases, better than ex-pected. However, if glass researchdoes not yield a good solution andpath for mitigating risks, or simplyproves too costly to manufacture, asteel or titanium personnel spherecan certainly be used but at a weightand view penalty.

Testing and SafetyWe investigated pressure testing

facilities around the world becausewe did not want to have to extrapo-late; we wanted actual test data from1.25× FOD pressure. We found that

FIGURE 6

Finite element analysis results showing absence of detrimental tensile forces in the model.


many facilities had decommissionedor de-rated their chambers due toage and safety considerations.

Collaborating closely with Avure(www.avure.com), DOER developedan innovative testing program usingthree different sizes of cold isostaticpresses or CIP chambers. Thesetools will allow us to conduct a fullrange of destructive materials testing,scale model testing, and ultimatelypressure testing of the personnelspheres to 1.25 × FOD. Under-taking this program will not onlyprovide the data we require forDeepsearch, but it will also becomean asset to the entire marine com-munity, replacing aging hydrostatictest chambers with safer, modernalternatives.

BatteriesBatteries were not nearly as daunt-

ing a task given the tremendous influxof new research in the area. Selectionevaluation criteria include■ Chemistry■ Availability■ Cycle Life■ Safety/Handling■ Energy density■ Packaging■ Cost■ Charging time■ Duration between charging

With the push in recent years to-ward electric vehicles, AUVs, andhigher energy densities, batteries arean area where technology is evolvingat an incredible pace. Thus, the ma-jority of research surrounded han-dling, packing, charging protocols,and testing. However, because ofthis rapid evolution and the potentialinconsistencies in package sizes andmanufacturing, our design must beadaptable. Oil-filled housings are at-

tractive if we can be assured of con-sistent package size and chemistry.The alternative is to develop one-atmosphere, ceramic housings. Bothpaths are being investigated.

Battery power is split into three sys-tems: main/propulsion, house/hotelpower, and emergency power. Themain power is for the rapid descentand ascent assist and slower speed ma-neuvering while at work. House poweris used for ancillary devices such aslights, cameras, and sampling systems.Emergency power is for critical func-tions in the event of main power loss.

Most shallow-water submersiblesstill use lead acid gel cell batteries.Deep research submersibles haveused chemistries, including silver/nickel, nickel /cadmium, and nickel /hydride (Takagawa et al., 1995). A re-cent trend has been toward Lithiumchemistries, including lithium ionand lithium polymer. These havebeen proven in AUVs for a numberof years but require additional safety/handling steps. Germanischer Lloyds(www.gl-group.com) has approved alithium battery for use in the smalltwo- and three-person u-boatworxsubmersibles (www.uboatworx.com)and has implemented new rules forvehicles rated for 6,000 m and below.

On a larger scale, the Navy usedproprietary lithium battery chemistryin swimmer delivery vehicles until abattery fire shut down their most re-cent project. While the cause of thataccident is not openly known, thecommon belief is that it was a han-dling problem and not a manufactur-ing defect. For Project Deepsearch,we are trending toward lithium ionbattery chemistry, which has beentested and approved by the Navywhile developing more stringent han-dling protocols to minimize risk.

FloatationSyntactic foam is a great material

and was a boon to the industry whenit was introduced in 1964. However,for FOD applications, it simply be-comes too great a weight penaltyresulting in an impractically largesubmersible. Additionally, high per-centage water absorption requiresa larger variable buoyancy system(VBS) to compensate. Syntactic foamcan be used but at a size and weightpenalty for the design. For the Deep-search submersible, ceramic spheresappear to be the optimum solution ifthe fol lowing quest ions can beanswered:■ Can they be economically manu-

factured in sufficient quantities?■ Will sympathetic failure be an

issue?■ Can packaging mitigate sympa-

thetic failure?■ Is fatigue a factor, and if so, can

they be acoustically monitored forfatigue before failure?

■ Can they be tested thoroughlyenough to obtain a manned rating?We worked to team with an off-

the-shelf provider who later declinedto bid. We dug deeper and foundCustom Technical Ceramics (www.customtechceramics.com), a providerwho was willing to collaborate onboth new and existing ceramic/metalcombinations to truly optimize adesign.

The 2009 success of the WoodsHoleNereus ROV proved that ceramicspheres could go to FOD (http://www.whoi.edu/page.do?pid=10076&tid=282&cid=57586).

Our task is to optimize the designand to work with an independentclassing agency to have the spheres ap-proved for use on a human-occupiedsubmersible. To do this, we have to


break some balls, literally. This can beaccomplished in a small 60,000 psiCIP chamber. Destructive tests on theceramic spheres will provide the Kfactor necessary for full analysis anda step towards classification.

Foremost is the concern aboutsympathetic failure. With a tightpacked array of thousands of spheres(Figure 7), sphere design must be ro-

bust enough to absorb the collapse ofa flawed or damaged sphere. A chainreaction could result in the loss of theprimary submersible floatation. A firststep is to increase the overall strengthand toughness of the sphere design.This requires more material, at a lossof buoyancy efficiency, or movingto a more advanced ceramic. Addi-tionally, the matrix the spheres arepacked in can be used to absorb theshock wave generated by the collapseof a flawed sphere.

It was initially hoped this matrixcould be conventional FOD syntac-tic, increasing package efficiencyeven more. However, difficulties andcost in fabrication of this methodmake it prohibitive. Casting of thespheres in a syntactic slurry and cur-ing as a monolithic assembly haveproven to stress the ceramic spheresin an unacceptable manner, initiat-ing buckling at lower than design

pressures. Two dimensional, thethree-dimensional assemblies of thepackaging with these high strengthspheres will be tested for sympatheticfailure resistance in a chamber atFOD. The inner sphere can be inten-tionally flawed to force failure atFOD or other depths.

In researching ceramic materials,we learned that once the spheres are“set” at a high stress level, meaningthat they no longer propagate flaws(which translates to noise, the KaiserEffect) when cycled to a lower stresslevel in a chamber, that they thenwill not fail even after thousands ofcycles. Is there a fatigue limit? If so,can flaws propagating prior to fail-ure be monitored acoustically as awarning?

Answers to these questions andconsistent proof of design, manu-facturing reliability, and long-termsafety will all have to be satisfactorilyaddressed if we are to incorporatethem into the floatation system of ahuman-occupied submersible.

Today and TomorrowBy April of 2009, the research

phase was complete, but we wantedto continue with some additional re-search on glass—the highest risk com-ponent in terms of testing and ease ofmanufacture. Much has been learnedand more work is ahead.

We published many of our find-ings at the project Website, www.deepsearch.org. In the meantime, wedeveloped a plan to build a 1,000 mtest platform, which would enable usto test and qualify the design in allother areas and continue pressurecycle testing materials and componentsfor deeper work using an acrylic per-sonnel sphere. In no way would thedesign be one that we would conceive

if our job was to build a 1,000 msubmersible. However, it was theoptimal depth for a test platform andwould allow us to use an acrylicpersonnel sphere of the same inter-nal diameter as the all glass design,68 inches.

Today DOER has compiled a500-plus-page internal design docu-ment, and we are adding more in-formation weekly. When complete,it will provide the build plan for thetest platform and carry over into theFOD systems as the targeted glass re-search is completed.

Additional funding for document-ing the research is being sponsored bythe Marine Science Technology Foun-dation (www.mstfoundation.org), andothers, both private and corporate, arebeginning to come forward. It is a bigstep ahead and a chance for collabo-rators and sponsors to make a sub-stantive difference in our ability tounderstand and explore the oceans inways heretofore unattainable.

Our goal is not to plant a flag50 years later in the Marianas Trench.Rather, our goal is to honor thatachievement of 1960 by buildingupon what Trieste started, and whatAlvin and others have achieved, andby providing science with tools withwhich they can make direct observa-tions at any point in the water col-umn anywhere in the world.

Although a submersible can usu-ally be more economically supportedby an ROV or AUV, having a pairof submersibles provides invaluablecollateral benefits. This has beenproven by the Mir and Johnson SeaLink operations. One sub supportsthe other and can provide rescue as-sistance. One can be outfitted withcameras while the other acts as thelighting platform. One can positionabove and photograph the other at

FIGURE 7

Ceramic floatation sphere matrix study.


work capturing, the so called “God’seye view,” building a far greater rap-port with the public and achievinggreater visibility in the media and adeeper appreciation for the oceansand their role in sustaining life onEarth.

To that end, our second goal is tohelp others better technology throughwhat we learn along the way. We maydiscover things that fail miserably at20,000 feet but are a breakthroughfor systems operating at 10,000 feet.We would like to see this philosophycarry over into the science itself withfindings and images made readilyavailable via platforms such as GoogleEarth or online databases such as theCensus of Marine Life that are openlyaccessible, allowing information toflow more freely, thus engaging thepublic and policy makers, expandingour knowledge about the oceans.

We still ask each other the “howmuch will it cost?” question every day.But in realizing the value of knowl-edge weighed against the price of igno-rance, each day that passes reminds usof how much it will cost if we do notdo this.

ReferencesBusby, R. 1969. Ocean surveying from

manned submersibles. Reprint, 2006. Mar

Technol Soc J. 40(2) (summer):16-29.

Craven, J. 1990. The geopolitical significance

of a deepest ocean presence. Mar Technol

Soc J. 24(2):13-15.

Forman, W. 1999. The History of American

Deep Submersible Operations. pp. 265-267.

Best Publishing, Flagstaff, AZ.

Garvey, R. 1990. Composite hull for full

ocean depth. Mar Technol Soc J. 24(2):49-58.

Rona, P. A. 2000. Deep diving manned

research submersibles. Mar Technol Soc J.

33(4):13-25.

Stachiw, J. 2003. Handbook of Acrylics for

Submersibles, Hyperbaric chambers, and

Aquaria. 1066 pp. Best Publishing, Flagstaff,

AZ.

Stachiw, J.D. 1990. Pressure resistant ceramic

housings for deep submergence unmanned

vehicles. Mar Technol Soc J. 24(2):59-62.

Takagawa, T., Momma, H., Hotta, H. 1995.

Advanced technology used in Shinkai 6500

and full ocean depth ROV Kaiko. Mar

Technol Soc J. 29(3):15-25.

Walsh, D. 1990. Thirty thousand feet thirty

years later. Mar Technol Soc J. 24(2):7-8.

Yano, Y. 2005. Exploratory study on engi-

neering ceramics pressure hulls for deep-sea

submergence services. Mar Technol Soc J.

39(3):49-55.

Additional ResourcesANSI AMSE/PVHO-1-2007. American

Society of Mechanical Engineers Pressure

Vessel Human-Occupied Safety Standard

Clark. ISBN: 0791830969. 170 pp.

Clark, A. 2000. Deep sea observatories. Mar


Earle, S., Giddings, A. 1980. Exploring the

Deep Frontier. National Geographic Society.

296 pp. Washington, DC.

Earle, S. 1995. Sea Change. G.P. Putnam

Sons, New York, NY.

Earle, S. 2000. Why explore the deep sea?

Mar Technol Soc J. 33(4):80-82.

Hawkes, G., Ballou, P. 1997. The ocean

Everest concept: a versatile manned sub-

mersible for full ocean depth. Mar Technol

Soc J. 24(2):79-86.

Kohnen, W. 2007. MTS overview of manned

underwater vehicle activity. Mar Technol

Soc J. 42 (spring 2008):26-37.

Kohnen, W. 2005. Manned research sub-

mersibles state of technology 2004/2005. Mar

Technol Soc J. 39(3) (fall 2005):122-127.

Momma, H. 2000. Deep ocean technology at

JAMSTEC. Mar Technol Soc J. 33(4):49-64.

National Research Council. 1996. Undersea

Vehicles and National Needs. National

Academy Press, Washington, DC.

Nereus dive to Challenger Deep. http://

www.whoi.edu/oceanus/viewArticle.do?

id=57606&sectionid=1000 and http://www.

whoi.edu/page.do?pid=10076&tid=282&cid=

57586 (accessed November 2009).

Nereus vehicle. http://www.whoi.edu/page.

do?pid=24136 (accessed November 2009).

Ohno, D. et al 2004. A design study of

manned deep submergence research vehicles

in Japan. Mar Technol Soc J. 38(1) (spring

2004):40-51.

Robison, B. 2000. The coevolution of

undersea vehicles and deep-sea research. Mar


Tsukioka, S. et al The PEM fuel cell systems

for autonomous underwater vehicles. Mar

Technol Soc J. 39(3) (fall 2005):56-64.

UNOLS (University National Laboratory

System). 1994. The Global Abyss: An As-

sessment of Deep Submergence Science in the

United States. UNOLS Deep Submergence

Committee. 53 pp. www.unols.org.

University National Laboratory System,

Narragansett, Rhode Island.

Walsh, D. Feb/Mar 1980. Twenty years after

the “Trieste” dive. Archive paper, vol. 14,

No. 1. Mar Tech Soc J. 40(2) (summer

2006):105-111.

www.wikipedia.org/wiki/Mount_Everest

(accessed November 2009).


Excerpt from The Sea: A New Frontier, 1967

Guest Editor’s note:As this journal was coming to-

gether, we found a book writtenwhen bathyscaphs ruled the deepsea. The Sea: A New Frontier, byDonald MacLean, Department ofEducation, San Diego County, andSam Hinton, Scripps Institution ofOceanography, was published in1967. I knew Sam from my days atScripps and looked for him as we pre-pared for this issue.We think Don andSam’s words bring back a sense of thepeople and how they felt at that time.

But rather than considering thisexcerpt as just a look back, we are plac-ing it in the section of this volume thatfocuses on education. And if it is abouteducation, it is about the future. “In aperfect world,” said Lee Iacocca, “thebest of us would be teachers, and therest of us would have to settle forsomething less.”

Following the book excerpt, youwillfind a paper by two current teacherswho demonstrate that students stilllearn best when building thingshands-on. Like I did. And probablyyou, too. Trieste is the vessel they useto explore science.

To you mariners of the deep-est abyss: the legend of Trieste liveson with a new generation! Thishands-on science project was createdfor this issue of the Marine TechnologySociety Journal in tribute to you. Al-ready one of the author-teachers haspresented the project at a local teacherworkshop in San Diego. By the publi-

cation of this issue, teachers every-where will find detailed step-by-stepinstructions online.

Perhaps some pre-teen studentswill discover they have a knack forocean science and engineering. Theymay pursue their interest, and a ca-reer, that could well extend into thelatter half of this 21st century.

And the memory of that day50 years ago, when water ballasttanks were flooded and the dive wasbegun, will journey with them.

Kevin Hardy

Foreword by Nancy TaylorK-12 Science Coordinator,San Diego County Officeof Education

The San Diego County Office ofEducation is proud to assist in providingscience education resources like this toinspire tomorrow’s innovators. Whilewe learn from the past, we are indeed in-spired to use this information to developnew technologies for research and dis-covery. San Diego’s story of innovatorsand innovation is told in the pages ofthis journal with a unique approach.Middle school teachers and their stu-dents in San Diego and beyond havethe opportunity to look back to the in-novators whose incremental discoveriescoalesced into the bathyscaphe Trieste.The following pages tell students thestory of Trieste, discussing both sub-mersible engineering and the pioneerspirit. This historical perspective addsmotivation to a new era of innovationand engineering that is emerging inour nation and especially in our region.

Thank you, MTS, for thinking ofthe students and teachers who willbenefit from this work.

FIGURE 1

Trieste Program Director and Science AdvisorAndy Rechnitzer and his son, David, look at abook for young students about the DeepestDive.


Seven Miles Deep(Reprinted from the book, “The Sea: A New Frontier,”

written in 1967 by Donald MacLean, Department of Educa-tion, San Diego County, San Diego, CA, and Sam Hinton,Head Aquarist, Scripps Institution of Oceanography, LaJolla, CA, and published by the California State Depart-ment of Education, Sacramento, CA, 1967).

This chapter is a story of the development of a craftthat brought man to the bottom of the Marianas Trench,35,780 feet below the surface of the Pacific Ocean. It is astory of two men who looked through the window of an

observation sphere, switched on powerful searchlights,and saw ghost-like shrimp feeding on an ocean floor over7 miles deep, an ocean floor where the pressure is over

8 tons per square inch. It is the story of the “bathyscaph,”a name made from the Greek words “bathy” meaning“deep” and “skaphē” meaning “light boat.” The story ofthe bathyscaph Trieste is a strange and exciting one.

Yet like most stories of scientific achievement, the storyof the bathyscaph began years earlier.

The story starts with Auguste Piccard, physicist and bal-loonist. Piccard first conceived of a bathyscaph when he was acollege student in Zurich, Switzerland. Piccard did not go tothe ocean to prove it his theory, however. Instead, he devel-oped a hermetically sealed observation sphere, which would

keep a man safe in a self-contained, pressurized living spaceor environment. The pressurized observation sphere was at-tached to a giant balloon.


Instead of moving downward into the ocean’s depths,Piccard’s observation sphere carried him 11 miles into theair. The observation balloon was named FNRS. The ini-tials “FNRS” refer to Fonds Nationale de la Recherche Scien-tifique, from the Belgian government, which financed thedevelopment of Piccard’s first balloon research. The flightof the FNRS convinced Piccard that the same type of ob-servation sphere might be used to explore the depths of theocean.

While Piccard was making his successful balloon as-cension in 1932, two Americans, Dr. William Beebeand Otis Barton, were exploring new ocean depths in asmall deep diving sphere called a “bathysphere.”

William Beebe was lowered in the bathysphere to adepth of 3,028 feet. He was the first man to see thestrange new world of darkness where fish carried theirown light. The accounts of his dives are filled with excit-ing and weird stories of never-before-seen sea creatures.But the bathysphere was dangerous, perhaps even moredangerous than Beebe realized. The cable on which thebathysphere was attached could have been broken easilyunder the weight of the observation sphere or from thesheer weight of the cable itself. The bathysphere was notable to move along the bottom of the ocean either.


Piccard read accounts of Beebe’s undersea explora-tions and decided that the bathysphere had many seriousdisadvantages. Piccard reasoned that man needed a craftthat was able to move about the bottom of the ocean with-out attached cables. An observation sphere had to be builtthat would withstand extreme pressures and at the sametime be attached to a craft that could be made to be lighterthan water.

Piccard had an idea. The observation sphere could beattached to several large steel floats. The floats would notcontain air, however, because they would easily collapseunder the extreme pressure. Instead, high octane aviationgasoline would be pumped into the floats. Gasoline,being lighter than water, would prevent the floats from cav-ing in under the extreme pressure.

Weights, called ballast, could be attached to the vessel toallow it to sink to the bottom. To return to the surface, theweights or ballast could be released, and the vessel wouldfloat to the surface. As Piccard planned and experimentedwith his dream of an undersea craft that would go to theoceans’ depths, Hitler was seizing power in Germany. Sud-denly in 1939, all of Europe was at war, and Piccard’sbathyscaph had to wait for peacetime.


In 1948, Piccard’s long-awaited bathyscaph was com-pleted. It was called FNRS-2, named for the same groupthat financed his famed observation balloon and nowpromised to help build his new bathyscaph. It was astrange looking craft, looking more like a dark steel bal-loon than a craft that would take man 25 times deeperthan a submarine.

The new bathyscaph, FNRS-2, contained six large floatsthat were filled with aviation gasoline. Each float was de-signed so that sea water could enter its underside as thecraft went down into deeper water. This allowed equaliza-tion between outer and inner sides of the float tanks, keep-ing the tanks from being crushed by water pressure. Becausewater pressure was equal on both sides of the float tanks, themetal could be thin. This allowed the float tanks of thebathyscaph to be lightweight and rather inexpensive tobuild.

Attached to the six gasoline floats was the observationsphere. Its walls were three and one-half inches thick, andit contained equipment that would keep two men aliveduring the dives. Two small propellers propelled thecraft. To submerge, the bathyscaph was loaded with ballast.The ballast was in the form of an iron shot, which could bereleased as needed.

In 1948, the unmanned bathyscaph, FNRS-2, dove to4,620 feet. Convinced of its safety, Piccard took theFNRS-2 on its first and last manned dives to 3,300 feet.

The bathyscaph FNRS-2 was a success. Piccard provedto the world that the depths of the ocean could be ex-plored in safety. Before Piccard’s bathyscaph, man had de-pended upon the submarine. But the submarine had to bedesigned to withstand the total pressure of the depth. Nowman had proof that only the observation sphere need fightthe extreme pressure.


In 1953, the FNRS-2 was sold to the French Navy, andPiccard began working on a new bathyscaph designed totravel to the deepest part of the ocean. It was named thebathyscaph Trieste after the city of Trieste, Italy, which fi-nanced its construction. It was a larger, more streamlinedbathyscaph, containing five more gasoline floats. InSeptember 1953, Piccard’s Trieste reached a depth of10,200 feet.

During the same time, Piccard served as an advisor to theFrench Navy in its attempt to rebuild his older bathyscaphinto the newer FNRS-3. In 1954, the French Navy took theFNRS-3 down to 13,400 feet, breaking the Trieste record byover 3,000 feet. This record held until 1960.


In 1958, the Trieste was purchased by the UnitedStates Navy. It was outfitted for one place, the deepestplace in the ocean known as the Challenger Deep. Earlyin the 1960, the Trieste, manned by Auguste Piccard’s sonJacques and by U.S. Navy Lieutenant Don Walsh, wasgently set down on the floor of the world’s deepestabyss, 35,800 feet below sea level. Through the thickcone-shaped acrylic window of the observation sphere,the twomen saw living fish in the searchlights. Life existedin a world of total darkness and a pressure of eight tons persquare inch.

Man was fulfilling a dream that he had carried forcountless centuries. Man was exploring a new frontier!

The bathyscaph Trieste was still a crude, undersea researchvessel. It was expensive to operate because it required 9 tons ofiron shot to bring it to the required depths. This shot wasdropped onto the sea bottom as the bathyscaph rose. Thebathyscaph was dangerous because it was filled with high oc-tane aviation gasoline. It was slow moving, and it had a shortrange. It would be improved because the active minds ofscientists, technicians, and engineers are always dreaming ofbetter ways to explore the world in which we live.


OnApril 10, 1963, the nuclear submarineThresher sankin 8,400 feet of water with her crew of 129 officers and en-listed men. The bathyscaph Trieste was the only underseavehicle in the United States able to reach the depth wherethe Thresher lay. While the slow moving, 59-foot Triestewas not intended for search and rescue, it was brought byship to the scene of the Thresher disaster.

On the eighth dive, Commander James Davis, anoceanographer, and Lt. Commander Arthur Gilmoresighted the twisted wreckage of the ill-fated nuclear subma-rine. The Trieste’s mechanical equipment reached downand retrieved a twisted pipe about 5 feet long. Close exam-

ination of the pipe proved without a doubt that the Triestehad located the Thresher. This was to be the last of theTrieste’s 70 research dives for the U.S. Navy.

On January 17, 1964, a sturdier and more powerful bathyscaph, Trieste II, was launched. The original Trieste had a roundbottom.Trieste II has a flat bottom andwill float in shallower water.Trieste II ’s observation sphere is recessed into its body forbetter streamlining.Trieste II is 67 feet long, weighs 53 tons, and carries 45,000 gallons of aviation gasoline. It travels at 2 knots,twice the speed of the original Trieste.


Modeling the Trieste to Explore Densityand Buoyant ForceA U T H O R SMarilyn SniffenHillsdale Middle School,El Cajon, CA

Michelle HardyNativity School,Rancho Santa Fe, CA

Introduction

Often we see students memorizingdefinitions for mass, volume, density,and buoyancy. And they are usuallyable to calculate density and buoyantforce, but once they are able to applythese principles to a real-life situation,the concepts take on new meaning.In this activity, students use the con-text of the historic Trieste bathyscaphto measure mass and volume, to cal-culate density, and to build a workingmodel of a submersible. After buildingthe model, students develop hypothesesand test their model to observe it in ac-tion. Students are amazed to see anddemonstrate some of the physics behindthe Trieste submersible and the creativeuse of different densities to conquer thedeep. Amidst their delight and total en-gagement in working with the modelsand testing their hypotheses, our middleschool students began to make the im-portant connections about density andbuoyant forces.

Learning ObjectivesPractice measuring mass and vol-

ume as well as calculating density.Explain how the density of an object

determines whether it sinks or floats.Describe the effect of buoyant

force.

Demonstrate how the Trieste useddiffering densities to manage buoyantforce.

Science Process SkillsStudents will measure mass and

volume of difference substances, cal-culate density and buoyant force,build a model, make and test hypoth-eses, record and analyze data, and drawconclusions.

California ContentStandards

Grade 8—(2 a, b, c, d, e) (8 a, b,c, d) (9 a).

Historic ContextIn the 1930s, there was a growing

scientific and public interest in explor-ing the deep sea. The challenge ofbuilding a personnel sphere to with-stand the high pressure was coupledwith the challenge of how to float it.Auguste Piccard, the inventor of theTrieste, was a physicist and balloonistwho looked at these challenges froma different perspective. He used differ-

ences in density to provide a creativesolution to the challenge of ascendingfrom great ocean depths. Piccard de-signed and built several bathyscaphsand in 1953, he completed his secondbathyscaph, theTrieste. His goal was togo deeper than anyone had ever gonebefore. Using gasoline and iron shot,the crew of the Trieste was able to ad-just their buoyancy to successfully diveand return to the surface from depthsgreater than anyone had before.

Education StandardsEighth grade Science Standards in-

clude that students know that a forcehas both direction and magnitude(2a) and that all forces acting on an ob-ject have a cumulative effect (2b).They must know that when the forcesare balanced on the object, its motiondoes not change (2c), but when theforces are unbalanced, the object’s mo-tion changes. (2e) Students must beable to identify the forces acting onan object (2d). They must know thatdensity is mass per unit volume andthat it can be calculated by dividingan object’s mass by its volume. Theymust learn that floating or sinking


can be predicted by comparing densi-ties of fluids and objects within thefluids. Finally, they must know thatthe buoyant force is equal to the weightof the displaced fluid. (8 a,b,c,d) In ad-dition, they are expected to use andunderstand the scientific methods ofinvestigation and experimentation(9a,f ). It’s no wonder that many ofthem find it somewhat difficult tograsp. It is not until they are able toapply these things to what they enjoyand are familiar with that they really un-derstand the concepts and how they arerelated. This activity does just that. Itbrings them to that “Aha!” momentwhen the light turns on (Figure 1).

ManagementBefore introducing this activity, the

basic concepts of mass, volume, density,gravity and weight, buoyant force, andthe scientific method for investigationand experimentation are introduced.

Students should be familiar withusing the measuring equipment andhave done several activities calculatingthe mass, volume, and density of vari-ous objects. They should be familiarwith the behavior of fluids of differentdensities and should be familiar withwhy things float or sink. This can bedone through several related activitiesthat use all the learning modalities.

On the day of this activity, I intro-ducemy students to theTrieste “bathy-scaph.” Photos and diagrams help thestudents to see the connection to theactual model they will be using. I askthe students what the designers neededto know about their bathyscaph be-fore they could be certain it was safeto put into the water. They suggestthat they would need to know if itwould float in the water, and I ask

them how they could find this infor-mation without actually putting it inthe water. When they determine thatthey could calculate its density andcompare it to the density of the water,wemove to the next question. I ask, if itdoes float, what needs to be done to itto make it sink. Most will quickly sayadd weight to it. Then I ask how theywill know how much weight needs tobe added. When they determine thatthey need to calculate its buoyantforce, and then add more weight thanthe buoyant force, I ask the final ques-tion. What needs to be done to allowthe bathyscaph to return to the sur-face. By now, they can easily see thatthe weight needs to be removed.■ Bathyscaphs are independent,

deep-diving vessels for underwaterexploration

■ The Trieste was the first bathy-scaph designed by the Swiss in

1953. It had a high-pressure sphereand a very large tank filled with gas-oline. Gasoline is less dense thanwater and does not compress, orsqueeze, which allows it to keepits buoyancy.

■ The Trieste displaced 50 tons of seawater and carried 9 tons of iron bal-last (Figure 2).Using a model of the Trieste filled

with oil instead of gasoline, students

determine its density, its buoyantforce, and the amount of mass neededto make it neutral in tap water. Thenthey test their hypotheses by placingthem in the tank. Finally they addmore mass and a release mechanismto determine if it will sink to the bot-tom of the tank and then return to thesurface (Figure 3).

Further ExplorationsIf time permits, students are en-

couraged to try other explorationswith their models such as:Will you have the same results if youtest your hypotheses in salt water?Will adding more mass slow the ascenttime?Will adding more mass speed the sink-ing time?Can you think of any other releasemechanisms for the Trieste model.

FIGURE 1

Eighth grade students find neutral buoyancyfor their model of Trieste.

FIGURE 2

A schematic drawing of the bathyscaph Trieste that carried explorers to the deepest place in the ocean.


Will it work in the deepest end of apool?Will it work in saltwater, like off a dockin the bay?

ObjectiveThe objective for this activity is to

explore how mass and volume affectdensity and buoyant force.

Materials and LabPreparation/Assembly

Tools needed:

1. Hot melt glue gun with sticks

2. Push pin

3. Needle nose pliers, 2 pairs

4. Diagonal small cutters

5. Drill

6. Drill bits, 1/16 and 1/8 inches

7. Whisk broom, dust pan, andtrash can for clean up

8. Funnel

9. Magic Marker or Sharpie

Materials needed, for each bathy-scaph model:

1. Water bottle, 16.9 Fl. Oz,empty, with lid, remove label

2. Washer, garden hose

3. Screw eye, small

4. Golf ball

5. Vegetable oil, to fill water bottle

6. Alka Seltzer® tablets, 2 each

7. Paper clips, medium, 2 each

8. Rubber bands, 2 each, medium

9.Two lids from35-mmfilm canisters

10. Paper towels

11. Sharpie indelible pen

12. Test tank. A 10-inch diameter ×24-inch glass cylinder is availablefrom many wholesale flowershops for about $50.

13. Siphon hose to drain test tank

14. buckets to fill/drain test tank

15. Large galvanized steel flat washersfrom the hardware store, totalweight = 3 oz

16. Tap water

17. Twist ties

Process (Build the Parts!)Bathyscaph Body

1. Plan construction in a place whereif oil is spilled, the mess is con-tained and does not become a big-ger problem.

2. Plug in hot melt gun and let itcome up to temperature.

3. Place empty water bottle on a sheetof paper towel or in a sink. Using thefunnel, fill the water bottle with veg-etable oil to full. Screw cap looselyonto water bottle. Squeeze bottleslightly to remove any remainingair. Tighten cap. Clean exterior of

bottle with dish soap to removeany oil on the outside.

4. Gripping the center of the water bot-tle with your thumb and center fin-ger like a teeter-totter, locate thecenter of mass of the filled water bot-tle.Mark the spot with a Sharpie pen.

5. Using the push pin, make a pilothole in the golf ball for the screweye. Install the screw eye into thegolf ball. This will serve as the anchorattachment point later.

6. Using preheated glue gun, glue thegarden hose washer to the side ofthe water bottle. Fill the center ofthe hose washer with hot glue andstick in the golf ball with the screweye pointing directly away from thewater bottle. The bathyscaph ve-hicle is now complete (Figure 4).

Anchor

7. Weigh 3 oz of washers (ormass deter-mined by experiment as described).Run a twist tie through the centerof the washers, plus one mediumpaper clip. The paper clip will bethe hook to attach to the rubberband in the release later (Figure 5).

ReleaseEach release uses two 35-mm film

canister lids and a paperclip bent to

FIGURE 4

Student glues “personnel sphere” to buoy-ancy tank.

FIGURE 3

A working model of the bathyscaph, demon-strating application of differences in density.


make a hinge. Drilled holes are done toboth lids the same. Segments of theedges are clipped differently dependingon which half it is (Figure 6).1. Layout 35-mm film canister lids

and medium size paper clips forthe number of releases to be made.

2. With Sharpie, make alignment markto establish a “top”position on all lids.

Important, this initial positionwill now be referred to as “top.Other positions will be referredto as “bottom” , “ l e f t ,” and“right.Note the two concentric“ridges” that make the snap sealwhen placed on the film canister.

3. Drill a single 1/16-inch diameterhole at the “top” between tworidges near edge as shown.

4. Drill three 1/8-inch diameter holesin a vertical line in the center sec-tion running from “top” to “bot-tom” as shown.

5. Modify all lids this way.6. Separate lids into two equal groups.7. Modify one group by clipping a

single 1/8-inch wide gap throughboth ridges at the “bottom” posi-tion (the side opposite the “top”).

8. Modify the second group by clip-ping a 1/8-inch wide gap throughthe outer ridge at two locations, atthe “left” and the “right” as shown.

9. Another view of modified secondgroup. Note inner all is not clipped.

10. Release will use one lid from eachgroup. Both are placed flat sidedown, ridges up, with 1/16-inchdiameter holes at “top.”

11. Using the needle nose pliers, bendthe paper clip straight and makehinge by running the wire throughthe 1/16-inch diameter holes. Bendthe wire at the top to make a“hook” like a Christmas tree or-nament hander.

12. Slide lids apart and place AlkaSeltzer® tablet in center of release.

13. Place rubber band smoothlyaround Alka Seltzer® tablet, withexcess brought through gap at bot-tom that was cut in Step 7 above.

14. Close release by sliding the top lidover the bottom lid capturing theAlka Seltzer® tablet and rubberband inside.

15. Another view of release whenclosed.

16. Use second rubber band to hold re-lease closed. Note rubber band iskept from sliding off by droppinginto the gaps cut in Step 8 above.

17. Attach weights to rubber bandcoming out of bottom of release.Release is now ready for attach-ment to bathyscaph screw eyeusing hook at top (Figure 7).

Materials for Each Group ofFour Students

Water bottle filled to brim with ca-nola oil, lid tightened, then sealed withhot glue

golf ball with hose washer andscrew eye attached

Trieste model (oil filled bottle withgolf ball and attachments glued together)

100-ml graduatedcylinder

triple beambalance

250-ml graduatedcylinder

15–20 washersof various sizes

two rubber bands

Release apparatus two to four AlkaSeltzer® tablets

Paper clips

Equipment Positioned at Sinksor on Counter

■ three each, 10-inch diameter ×24-inch tall glass tanks (availablefrom Florist shops)

■ three displacement cans■ three, 2-L graduated cylinders■ three long sticks with magnet at-

tached to endShopping list : 3 gallons of canola oil,

18 empty water bottles, 18 golf balls,

FIGURE 6

Assembly of the release. When seltzer tablet dis-solves, rubber band falls out, releasing weight.

FIGURE 7

Anchor weights attached to rubber band ofrelease.

FIGURE 5

Fishing sinkers or flat washers work well forweights.


18 hose washers, 18 screw eyes, 1 box small paper clips, hot glue gun with hot glue, 18 film canisters with lids, a 1/8-inchdrill, lots of Alka Seltzer® tablets, 3 long sticks, 3 powerful magnets, 3 tall clear glass tanks (we found 10-inch diameter × 24-inchtall clear cylindrical glass vases at a florist shop that worked very well for about $50 each, a real steal!)

Preparation Before LabThere is a considerable amount of time needed to prepare for this activity; however, once the models are made, they are

reusable each year. I had help with the release mechanisms, but the rest of the preparation took about 4 h (well worth the timeand effort for years of use).■ 9 release mechanisms need to be drilled and assembled in advance■ 9 Trieste models filled, assembled and glued together■ 9 water bottles filled with oil and glued shut■ 9 golf balls with hose washer glued on and screw eye attached■ Glue magnets to three long sticks

Procedures/Student Lab Sheet, Assessment

STUDENT WORKSHEET

Name________________ Science Period______________

Exploring Density and Buoyant Force with a Submersible

Objective: Demonstrate by using the lab equipment provided how mass and volume affect density and buoyant force.

Observations (background information on Power Point): We have a model of the Trieste bathyscaph. It is not filled withgasoline, but it is filled with oil. We need to know if the TriesteModel is less dense than water, and therefore will float. Todetermine the density of the model, divide its mass by its volume. After determining the density, we will calculate thebuoyant force on the model and determine the amount of mass needed to make it neutral in the water. (same density ofwater; 1 g/cc)

Finding Mass: Find the mass of the Trieste model with the balance and record this information on your Data Tablebelow.

Finding Volume by displacement: Finding the volume of the Trieste model will require 3 steps because the model istoo large to fit into our biggest graduated cylinder.

Step 1: Place the filled bottle of oil inside a 2-L graduated cylinder that has 1000 ml of water in it. Gently submergethe bottle using a pencil, so that the pencil does not go below the surface of the water. Read and record this new level ofwater with the bottle in it. Subtract the original 1000 ml from the new amount. This will give you the volume of thewater displaced by the bottle of oil. Record this as the volume of the oil filled bottle.

Step 2: Use a filled displacement can at the sink to find the volume of the sphere (golf ball with attachments).Catch the displaced water with an empty graduated cylinder. This will be the volume of the sphere. Record this asvolume of sphere.

Step 3: Add the volumes from steps 1 and 2. This should equal the total volume of the Trieste model. Record thisas volume of Trieste Model on the Data Table.

Calculating Density: Now that we have determined the mass and the volume of the Trieste model, calculate itsdensity by dividing its mass (g) by its volume (cm3). Record the density of the Trieste model on your Data Table. Isthe model less dense than water (1.0 g/cm3)? ______ Will the model float in the water?_________

Ask a Question: What is the amount of mass that needs to be added to the Trieste model in order to make it neutral(1.0 g/cc)? Then after increasing the mass so that it will sink to the bottom of the tank, what needs to be done to returnit to the surface of the tank?________________________________


Make a Hypothesis: To give a good possible answer to the question, you need to know how much buoyant force that thewater has on the Trieste Model.

Calculating Buoyant Force: To determine the buoyant force, we will need to know the weight of the displacedfluid. In this case the fluid is water, which makes things easier, because theweight (for which we will substitute mass) ofthe water equals its volume. You have already determined the volume of the displaced fluid for the Trieste model whenyou were finding its density. So this volume is also the mass of the displaced water and, therefore, the buoyant forcepushing up on the object. Record this as buoyant force on your data table.

Now you can make an educated guess, as some hypotheses, are called. You simply need to subtract the massfrom the buoyant force. The result will tell you how much mass added to the Trieste model will make it neutral (1 g/cc) inwater. Record this result as your hypothesis.

Test the Hypothesis:

Assemble the Trieste model with the added mass from your hypothesis. Take your prepared model to the tank of waterand gently place it into the water. Observe what happens. Could you make your model neutral in the water? __________Now add another weight to your model with a release mechanism.

Did the model sink? __________________

What changed about the model to allow it to sink? ____________________

Did the model rise back to the surface? ___________What changed about the model to allow it to rise?__________

Conclusion:

Was your hypothesis correct?___________ How much mass made your model neutral? ___________ sink? ________

Which changed in this experiment, the density of the model or the buoyant force on the model?____________________

Data TableMass of Trieste Model = ________ gVolume of oil filled bottle = ________Volume of sphere = ________Volume of Trieste Model = ________Density of Trieste Model = ________Mass of displaced water = ________Buoyant Force of water on model = ________Your hypothesis of weight to make neutrally buoyant = ________

AssessmentCompare data.Discuss how it went.

Independent StudyLet’s try the deep end of the pool! (Figures 8 and 9).

More InformationGo to <http://www.materover.org> and search for “bathyscaph project.” You’ll find step-by-step photos show-

ing how to make your own working Trieste model including the Alka Seltzer® release!


You can also search the web andlearn about the amazing world ofocean engineering and underseavehicles.

AcknowledgmentsThe authors thank KevinHardy for

his help and encouragement with thisproject, and Michelle’s nephew, JustinLinvill, for helping build and test thefirst working model, including a diveto the deep end of the pool.

FIGURE 8

This bathyscaph explores the deep end of the pool.

FIGURE 9

Reflected in the surface, the bathyscaph returnsfrom a deep dive.


INDEX TO VOLUME 43

Acain, J. (1) 6-12, 13-20

Afzulpurkar, S. (3) 60-70

Asahina, J.K. (4) 116-126

Barclay, D.R. (5) 144-150

Barry, J.P. (5) 77-78

Bartlett, D.H. (5) 128-131

Basta, D.J. (4) 14-15

Beaujean, P-P.J. (2) 21-32

Beck, E. (1) 6-12

Below, D. (5) 105-109

Berk, T. (1) 6-12

Bingham, B.S. (2) 61-72, (4) 76-84

Bishop, C.B. (5) 15

Blankenship-Williams, L.E. (5) 137-143

Bolster, W.J. (1) 127

Bonsall, S. (3) 34-50

Bowen, A. (5) 65-76

Bragg, J. (1) 37-46

Brandenburg, E. (4) 62-75

Brashem, K. (1) 6-12

Brennan, M.L. (1) 47-49

Brockerville, L. (1) 37-46

Broderick, A.C. (3) 51-59

Brown, C. (3) 83-84

Brown, H.C. (2) 33-47

Brown, M. (3) 98-109

Brown, T. (1) 37-46

Brundage III, H.M. (3) 78-82

Buckingham, M.J. (5) 144-150

Busby, R.F. (5) 37-41

Button, C. (1) 37-46

Camilli, R. (4) 76-84

Caress, D. (1) 6-12

Carlson, E.A. (2) 21-32

Carton, G. (4) 3-4, 16-32

Casaine, R. (3) 85-97

Chaffey, M. (3) 98-109

Charles, M. (4) 41-51

Chou, C-C. (3) 71-77

Coles, M. (3) 98-109

Collins, S. (3) 98-109

Conrod, S. (4) 41-51

Cook, S. (3) 85-97

Crewe, S. (1) 37-46

Croff, K. (1) 4-5

Croff, K.L. (1) 93-100

Crout, R.L. (2) 13-20

Cruz, N. (1) 50-63

Cunha, S. (1) 50-63

Davis IV, A.D. (4) 11-13

De Carlo, E.H. (4) 85-99

Desa, Ehrlich (3) 60-70

Desa, Elgar (3) 60-70

Diamond, G. (3) 98-109

Dock, M. (4) 76-84

Doyle, G. (1) 37-46

Duryea, A.N. (4) 76-84

Eustice, R.M. (2) 33-47

Fisher, R.L. (5) 16-19

Fletcher, B. (5) 65-76

Flynn, M. (1) 37-46

Follett, G. (4) 127-131

Follett, M. (1) 37-46

Follett, S. (1) 37-46

Forman, W. (5) 27-36

Francken, F. (4) 52-61

Fraser, S. (3) 85-97

Freeman, M. (1) 37-46

Fujii, T. (5) 151-160

Fuller, W.J. (3) 51-59

Furneaux, A. (1) 37-46

Furushima, Y. (3) 13-22

Garcia, S.S. (4) 85-99

Godley, B.J. (3) 51-59

Goldberg, J. (1) 127

Greene, P. (4) 127-131

Grefe, N. (3) 85-97

Hafez, A.M. (4) 52-61

Hagen, P.E. (4) 100-104

Hansen, C.M. (4) 100-104

Hardy, K. (5) 6-7, 105-109, 123-127

Hardy, M. (5) 187-193

Hashimoto, J. (5) 77-78

Hawkes, G. (5) 164-168

Hayashi, K. (4) 116-126

Haynes, S. (2) 73-80

Henker, C. (4) 127-131

Higdon, J. (1) 37-46

Hillier, N. (1) 37-46

Hinton, S. (5) 178-186

Holloway, Leslie (3) 98-109

Holloway, Lindsay (3) 98-109

Hooker, S.K. (3) 51-59

Hornell, D. (1) 37-46

Hotaling, L. (2) 73-80

Howse, J. (1) 37-46

Howse, D. (3) 98-109

Hutchinson, B. (3) 85-97

Inoue, T. (3) 5-12; (5) 87-96, 97-104

Ishibashi, S. (5) 87-96

Jaeger, J. (5) 63-64

James, M. (5) 123-127

Jamieson, A.J. (5) 151-160

Jasper, I. (3) 85-97

Jasper, I.D. (1) 31-36

Jadot, C. (1) 64-72

Jagusiewicz, A. (4)16-32

Jakuba, M.V. (4) 76-84

Jung, J-B. (3) 78-82

Katsui, T. (5) 97-104

Kear, W.J. (5) 25-26

Keener-Chavis, P. (2) 73-80

Keyssar, A. (1) 127

Kim, A. (2) 33-47

Kirkwood, W. (1) 6-12

Kitts, C. (1) 6-12, 13-20

Koch, M. (4) 105-115

Kohnen, W. (5) 42-62

Krumholz, J. (1) 64-72

Kubic, C. (1) 73-92

Lågstad, P. (4) 100-104

Lawson, T. (5) 169-177

LeBouvier, R. (4) 76-84

Levin, L.A. (5) 137-143

Lewis, A. (1) 37-46

Long, T.P. (4) 5-10

MacDonald, K. (4) 85-99

MacLean, D.A. (5) 178-186

MacNeil, P. (1) 37-46

MacVean, C. (5) 63-64

Madhan, R. (3) 60-70

Mahacek, P. (1) 6-12, 13-20

Maillet, A. (3) 98-109

Manley, J. (1) 3, (2) 3

Martz, M. (2) 48-60

Maruyama, T. (3) 13-22

Mas, I. (1) 13-20

Mascarenhas, A. (3) 60-70

Matos, A. (1) 50-63

Maurya, P. (3) 60-70

McFarlane, J.R. (2) 9-12


Author Index

Merewether, R. (5) 110-114

Michel, J. (5) 20-22

Minay-Goldring, M. (1) 37-46

Mittendorf, K.E. (3) 23-33

Moghadam, M.K. (3) 34-50

Morrison, B. (3) 98-109

Moss, J. (3) 98-109

Murakami, H. (5) 97-104

Nagao, M. (3) 13-22

Nakajima, K. (3) 5-12

Nambiar, M. (3) 60-70

Navelkar, G. (3) 60-70

Neu, W. L. (2) 48-60

Neville, C. (1) 37-46

Oldford, S. (3) 98-109

Olsson, M. (5) 110-114

Osawa, H. (5) 87-96

Overfield, M.L. (4) 33-40, 85-99

Pascoal, A. (3) 60-70

Pausch, S. (5) 105-109

Pennell, J. (1) 37-46

Penney, B. (3) 98-109

Petrovic, O. (1) 13-20

Picco, W. (1) 37-46

Prabhudesai, S. (3) 60-70

Prechtl, E.F. (2) 61-72

Price, R. (1) 101-116

Priede, I.G. (5) 151-160

Quick, R. (1) 37-46

Ramsey, A. (1) 31-36, (3) 85-97

Rechnitzer, A. (5) 23-24

Reddy, V. (1) 6-12

Reyer, T. (4) 85-99

Roland, A. (1) 127

Rolfe, J. (4) 85-99

Rosenthal, B.J. (5) 8

Rynne, P.F. (1) 21-30

Ruck, W. (4) 105-115

Sagalevitch, A. (5) 79-86

Sanderson, J. (5) 110-114

Sawa, T. (5) 87-96

Sayle, S. (4) 41-51

Schwartz, A. (4) 62-75

Shimamura, T. (3) 5-12

Shimoyama, H. (4) 116-126

Shinkai, A. (4) 116-126

Shioji, G. (3) 5-12

Silva, S.R. (1) 50-63

Simonet, F. (5) 144-150

Skutnik, J. (1) 6-12

Sniffen, M. (5) 187-193

Solan, M. (5) 151-160

Stephenson, M. (4) 41-51

Straker, L.E. (1) 117-126

Suzuki, A. (3) 13-22

Suzuki, H. (3) 5-12

Symons, L.C. (4) 3-4, 33-40

Tahara, J. (5) 87-96

Takagi, K. (5) 97-104

Taylor, L. (5) 169-177

Tincher, T. (4) 132-138

Tosatto, M. (5) 161-163

Tørnes, J.A. (4) 100-104

Unlu, F. (3) 85-97

von Ellenrieder, K.D. (1) 21-30

Wall, A. (3) 34-50

Walsh, A. (3) 85-97

Walsh, Devin (1) 37-46

Walsh, Don (5) 9-14

Wang, J. (3) 34-50

Watanabe, Y. (5) 87-96

Waterman, E. (1) 37-46

Watson, J. (1) 37-46

Weston, S. (5) 110-114

Wheat, G. (1) 6-12

Whitcomb, L.L. (5) 65-76

White, D.A. (5) 115-122

White, M. (3) 98-109

Williams, H. (3) 85-97

Wilson, R.A (2) 61-72

Windeyer, T. (4) 41-51

Witt, M.J. (3) 51-59

Yamamoto, H. (3) 13-22

Yayanos, A.A. (5) 132-136

Yoerger, D.R. (5) 65-76

Yoshida, H. (5) 87-96

Young, J. (3) 98-109

Zande, J. (3) 83-84


INDEX TO VOLUME 43

Industry and TechnologyBuoy TechnologyHERMES—A High Bit-Rate Underwater Acoustic Modem Operating at High Frequencies for Ports and Shallow Water Applications, P.J. Beaujean, E.A. Carlson (2) 21-32

Insights into Habitat Utilization by Green Turtles (Chelonia mydas) During the Inter-Nesting Period Using Animal-Borne Digital Cameras, W.J. Fuller, A.C. Broderick, S.K. Hooker, M.J. Witt, B.J. Godley (3) 51-59

From Beebe and Barton to Piccard andTrieste, W. Forman (5) 27-36

Journey to the Challenger Deep: 50 Years Later With the Nereus Hybrid Remotely Operated Vehicle, B. Fletcher, A. Bowen,D.R. Yoerger, L.L. Whitcomb (5) 65-76

From the Bathyscaph Trieste to theSubmersibles Mir, A. Sagalevitch (5) 79-86

The ABISMO Mud and Water Sampling ROV for Surveys at 11,000 m Depth, H. Yoshida, S. Ishibashi, Y. Watanabe, T. Inoue, J. Tahara, T. Sawa, H. Osawa (5) 87-96

Crawler System for Deep Sea ROVs,T. Inoue, T. Katsui, H. Murakami, K. Takagi (5) 97-104

Under High Pressure: Spherical Glass Flotation and Instrument Housings in Deep Ocean Research, S. Pausch, D. Below,K. Hardy (5) 105-109

Flotation in Ocean Trenches Using Hollow Ceramic Spheres, S. Weston, M. Olsson, R. Merewether, J. Sanderson (5) 110-114

HADEEP: Free-Falling Landers to theDeepest Places on Earth, A. J. Jamieson,T. Fujii, M. Solan, I. G. Priede (5) 151-160

Cables and ConnectorDiving to the Deep: Uncovering theMysteries of Mid-Ocean Ridges, I.D. Jasper, A. Ramsey (1) 31-36

Trends in Emerging Tidal and Wave Energy Collection Technology, R. Price (1) 101-116


Site Assessment and Risk Management Framework for Underwater Munitions, S. Sayle, T. Windeyer, M. Charles, S. Conrod, M. Stephenson (4) 41-51

Journey to the Challenger Deep: 50 Years Later With the Nereus Hybrid Remotely Op-erated Vehicle, B. Fletcher, A. Bowen,D.R. Yoerger, L.L. Whitcomb (5) 65-76

Pressure Testing: Best Practices, K. Hardy,M. James (5) 123-127

Deepwater Field Development TechnologyHistoric Disposal of Munitions in U.S. and European Coastal Waters, How Historic In-formation Can be Used in Characterizing and Managing Risk, G. Carton, A. Jagusiewicz(4) 16-32


DivingInsights into Habitat Utilization by Green Turtles (Chelonia mydas) During the Inter-Nesting Period Using Animal-Borne Digital Cameras, W.J. Fuller, A.C. Broderick, S.K. Hooker, M.J. Witt, B.J. Godley (3) 51-59

The Detection of Annual Hypoxia in a Low Latitude Freshwater Reservoir in Kerala, India, Using the Small AUV Maya, E.Desa, R. Madhan, P. Maurya, G. Navelkar, A. Mascarenhas, S. Prabhudesai, S. Afzulpurkar, E. Desa, A. Pascoal, M. Nambiar (3) 60-70

An Overview of Underwater Technologies for Operations Involving Underwater Munitions, A. Schwartz, E. Brandenburg (4) 62-75

In the Beginning… A Personal View,D. Walsh (5) 9-14


Human Exploration of the Deep Seas: Fifty Years and the Inspiration Continues,W. Kohnen (5) 42-62

Swim Call, W.J. Kear (5) 25-26

Dynamic PositioningUnmanned Autonomous Sailing: Current Status and Future Role in Sustained Ocean Observations, P.F. Rynne, K.D. vonEllenrieder (1) 21-30

The Use of the RUST Database to Inven-tory, Monitor, and Assess Risk from Undersea Threats, M.L. Overfield, L.C. Symons(4) 33-40


Discarded Military Munitions Case Study: Ordnance Reef (HI-06), Hawaii, S.S.Garcia, K. MacDonald, E.H. De Carlo, M.L. Overfield, T. Reyer, J. Rolfe (4) 85-99

Manned Underwater VehiclesShallow Water Surveying Using Experimental Interferometric Synthetic Aperture Sonar,S.R. Silva, S. Cunha, A. Matos, N. Cruz(1) 50-63

Tethered and Untethered Vehicles: The Future Is in the Past, J.R. McFarlane (2) 9-12

U.S. Navy Involvement With DSV Trieste, C.B. Bishop (5), 15


The Old Arguments of Manned VersusUnmanned Systems Are About to BecomeIrrelevant: New Technologies Are Game Changers, G. Hawkes (5) 164-168

In the Trenches... Topside Remembrances by the Chief of the Boat, DSV Trieste, J. Michel (5), 20-22


Project Deepsearch: An Innovative Solution for Accessing the Oceans, L. Taylor, T. Lawson (5) 169-177

MooringsTrends in Emerging Tidal and Wave Energy Collection Technology, R. Price (1) 101-116

Subject Index


Oil and Gas Platform Ocean Current Profile Data from the Northern Gulf of Mexico,R.L. Crout (2) 13-20

Discarded Military Munitions Case Study: Ordnance Reef (HI-06), Hawaii, S.S. Garcia, K. MacDonald, E.H. De Carlo,M.L. Overfield, T. Reyer, J. Rolfe (4) 85-99

Oceanographic InstrumentationSeaWASP: A Small Waterplane Area Twin Hull Autonomous Platform for ShallowWater Mapping, E. Beck, W. Kirkwood,D. Caress T. Berk, P. Mahacek, K. Brashem, J. Acain, V. Reddy, C. Kitts, J. Skutnik, G. Wheat (1) 6-12

Unmanned Autonomous Sailing: Current Status and Future Role in Sustained Ocean Observations, P.F. Rynne, K.D. vonEllenrieder (1) 21-30

Ancient Shipwreck Survey and the Modern Submarine Landscape off Yalikavak, Turkey, M.L. Brennan (1) 47-49

The Underwater Cultural Heritage and Marine Scientific Research in the Exclusive Economic Zone, K.L. Croff (1) 93-100


The NOAA Ship Okeanos Explorer:Continuing to Unfold the President’s Panel on Ocean Exploration Recommendation for Ocean Literacy, P. Keener-Chavis,L. Hotaling, S. Haynes (2) 73-80

The Use of the RUST Database to Inventory, Monitor, and Assess Risk from Undersea Threats, M.L. Overfield, L.C. Symons(4) 33-40


Discarded Military Munitions Case Study: Ordnance Reef (HI-06), Hawaii, S.S.Garcia, K. MacDonald, E.H. De Carlo,M.L. Overfield, T. Reyer, J. Rolfe (4) 85-99

In the Beginning… A Personal View,D. Walsh (5) 9-14


Human Exploration of the Deep Seas: Fifty Years and the Inspiration Continues, W.Kohnen (5) 42-62

Journey to the Challenger Deep: 50 Years Later With the Nereus Hybrid RemotelyOperated Vehicle, B. Fletcher, A. Bowen,D.R. Yoerger, L.L. Whitcomb (5) 65-76

Under High Pressure: Spherical GlassFlotation and Instrument Housings in Deep Ocean Research, S. Pausch, D. Below,K. Hardy (5) 105-109

Recovery of Live Amphipods at Over 102 MPa from the Challenger Deep, A. A.Yayanos (5) 132-136

Offshore StructuresEvaluation of Dynamic Analysis Methods for Seismic Analysis of Drydocks, C. Kubic (1) 73-92




Joint Description Methods of Wind and Waves for the Design of Offshore WindTurbines, K.E. Mittendorf (3) 23-33


Trieste I Deepest Manned Dive Passes 35th Anniversary, A. Rechnitzer (5) 23-24

Flotation in Ocean Trenches using Hollow Ceramic Spheres, S. Weston, M. Olsson, R. Merewether, J. Sanderson (5) 110-114

Remotely Operated VehiclesSeaWASP: A Small Waterplane Area Twin Hull Autonomous Platform for Shallow Water Mapping, E. Beck, W. Kirkwood, D. Caress, T. Berk, P. Mahacek, I. Mas, O. Petrovic, J. Acain, C. Kitts (1) 6-12

Cluster Space Control of AutonomousSurface Vessels, P. Mahacek, I. Mas, O.Petrovic, J. Acain, C. Kitts (1) 13-20

Diving to the Deep: Uncovering the Mysteries of Mid-Ocean Ridges, I.D. Jasper, A. Ramsey (1) 31-36

ROV Pontus, J. Bragg, L. Brockerville, T. Brown, C. Button, S. Crewe, G. Doyle, M. Flynn, M. Follett, S. Follett, M. Freeman, A. Furneaux, J. Higdon, N. Hillier, D. Hornell, J. Howse, A. Lewis, P. MacNeil, M. Minay-Goldring, C. Neville, J. Pennell, W. Picco, R. Quick, D. Walsh, E. Waterman, J. Watson(1) 37-46

The Underwater Cultural Heritage and Marine Scientifi c Research in the Exclusive Economic Zone, K.L. Croff (1) 93-100


An Overview of Autonomous Underwater Vehicle Research and Testbed at PeRL, H.C. Brown, A. Kim, R.M. Eustice (2) 33-47

Experimental Research on Horizontal Rotation of Remotely Operated Vehicles Induced by External Forces Near the Surface of the Ocean, T. Inoue, H. Suzuki, T. Shimamura, K. Nakajima, G. Shioji (3) 5-12

ROV Viking SPEAR, I. Jasper, R. Casaine, S. Cook, N. Grefe, B. Hutchinson, A. Ramsey, F. Unlu, A. Walsh, H. Williams, S. Fraser (3) 85-97

ROV 水神 (Suijin), B. Morrison, A. Maillet, M. Brown, L. Holloway, J. Moss, L. Holloway, D. Howse, M. White, S. Oldford, J. Young,M. Chaffey, S. Collins, M. Coles, B. Penney, G. Diamond (3) 98-109


Discarded Military Munitions Case Study: Ordnance Reef (HI-06), Hawaii, S.S. Garcia, K. MacDonald, E.H. De Carlo, M.L. Overfield, T. Reyer, J. Rolfe (4) 85-99

Case Study: Skagerrak Wrecks and Measures to Reduce the Environmental Risk, C.M. Hansen, P.E. Hagen, P. Lågstad, J.A. Tørnes (4) 100-104

Technology Options Tested on the German Coast for Addressing a Munitions Hot SpotIn Situ, M. Koch, W. Ruck (4) 105-115

From Beebe and Barton to Piccard and Trieste, W. Forman (5) 27-36

A Look Back at the MTS Journal of June 1990: “A Deepest Ocean Presence”, J. Jaeger, C. MacVean (5) 63-64


Journey to the Challenger Deep: 50 Years Later With the Nereus Hybrid RemotelyOperated Vehicle, B. Fletcher, A. Bowen,D.R. Yoerger, L.L. Whitcomb (5) 65-76

Revisiting the Challenger Deep Using the ROV Kaiko, J.P. Barry, J. Hashimoto(5) 77-78


The ABISMO Mud and Water Sampling ROV for Surveys at 11,000 m Depth, H. Yoshida, S. Ishibashi, Y. Watanabe, T. Inoue, J. Tahara, T. Sawa, H. Osawa (5) 87-96

Crawler System for Deep Sea ROVs,T. Inoue, T. Katsui, H. Murakami, K. Takagi (5) 97-104

HADEEP: Free-Falling Landers to theDeepest Places on Earth, A.J. Jamieson,T. Fujii, M. Solan, I.G. Priede (5) 151-160

The Old Arguments of Manned Versus Unmanned Systems Are About to Become Irrelevant: New Technologies Are Game Changers, G. Hawkes (5) 164-168

Revisiting the Challenger Deep Using the ROV Kaiko, J.P. Barry, J. Hashimoto(5) 77-78

Renewable EnergyUnmanned Autonomous Sailing: Current Status and Future Role in Sustained Ocean Observations, P.F. Rynne, K.D. von Ellenrieder (1) 21-30

Demonstration of a New Technology for Restoration of Red Mangrove (Rhizophora mangle) in High-Energy EnvironmentsJ. Krumholz, C. Jadot (1) 64-72


Ropes and Tension MembersJourney to the Challenger Deep: 50 Years Later With the Nereus Hybrid Remotely Operated Vehicle, B. Fletcher, A. Bowen,D.R. Yoerger, L.L. Whitcomb (5) 65-76

Seafl oor EngineeringSeaWASP: A Small Waterplane Area Twin Hull Autonomous Platform for ShallowWater Mapping, E. Beck, W. Kirkwood,D. Caress, T. Berk, P. Mahacek, K. Brashem, J. Acain, V. Reddy, C. Kitts, J. Skutnik,G. Wheat (1) 6-12

Diving to the Deep: Uncovering the Mysteries of Mid-Ocean Ridges, I.D. Jasper, A. Ramsey (1) 31-36

ROV Pontus, J. Bragg, L. Brockerville,T. Brown, C. Button, S. Crewe, G. Doyle,M. Flynn, M. Follett, S. Follett, M. Freeman,A. Furneaux, J. Higdon, N. Hillier, D. Hornell, J. Howse, A. Lewis, P. MacNeil, M. Minay-Goldring, C. Neville, J. Pennell, W. Picco, R. Quick, D. Walsh, E. Waterman, J. Watson (1) 37-46


Crawler System for Deep Sea ROVs, T. Inoue, T. Katsui, H. Murakami, K. Takagi (5) 97-104

Underwater ImagingDiving to the Deep: Uncovering the Mysteries of Mid-Ocean Ridges, I.D. Jasper, A. Ramsey (1) 31-36

ROV Pontus, J. Bragg, L. Brockerville,T. Brown, C. Button, S. Crewe, G. Doyle,M. Flynn, M. Follett, S. Follett, M. Freeman, A. Furneaux, J. Higdon, N. Hillier,D. Hornell, J. Howse, A. Lewis, P. MacNeil, M. Minay-Goldring, C. Neville, J. Pennell, W. Picco, R. Quick, D. Walsh, E. Waterman, J. Watson (1) 37-46



Experiments with Broadband Sonar for the Detection and Identification of Endangered Shortnose Sturgeon, H.M. Brundage III, J. Jung (3) 78-82

ROV 水神 (Suijin), B. Morrison, A. Maillet, M. Brown, L. Holloway, J. Moss, L. Holloway, D. Howse, M. White, S. Oldford, J. Young, M. Chaffey, S. Collins, M. Coles, B. Penney, G. Diamond (3) 98-109

An Overview of Underwater Technologiesfor Operations Involving Underwater Muni-tions, A. Schwartz, E. Brandenburg (4) 62-75

AUV Sensors for Real-Time Detection,Localization, Characterization, and Monitoring of Underwater Munitions, R. Camilli, B.S. Bingham, M.V. Jakuba, A.N. Duryea,R. LeBouvier, M. Dock (4) 76-84

Discarded Military Munitions Case Study: Ordnance Reef (HI-06), Hawaii, S.S. Garcia, K. MacDonald, E.H. De Carlo,M.L. Overfi eld, T. Reyer, J. Rolfe (4) 85-99

Case Study: Skagerrak Wrecks and Measures to Reduce the Environmental Risk,C.M. Hansen, P.E. Hagen, P. Lågstad,J.A. Tørnes (4) 100-104


From the Bathyscaph Trieste to the Submersibles Mir, A. Sagalevitch (5) 79-86

Unmanned Maritime VehiclesSeaWASP: A Small Waterplane Area Twin Hull Autonomous Platform for Shallow Water Mapping, E. Beck, W. Kirkwood, D. Caress, T. Berk, P. Mahacek, K. Brashem, J. Acain, V. Reddy, C. Kitts, J. Skutnik, G. Wheat (1) 6-12

Unmanned Autonomous Sailing: Current Status and Future Role in Sustained Ocean Observations, P.F. Rynne, K.D. von Ellenrieder (1) 21-30

Shallow Water Surveying Using Experimental Interferometric Synthetic Aperture SonarS.R. Silva, S. Cunha, A. Matos, N. Cruz (1) 50-63


HERMES—A High Bit-Rate Underwater Acoustic Modem Operating at High Frequen-cies for Ports and Shallow Water Applications, P.J. Beaujean, E.A. Carlson (2) 21-32


Design Requirements for Autonomous Multi-vehicle Surface-Underwater Operations, B.S. Bingham, E.F. Prechtl, R.A. Wilson (2) 61-72

The Detection of Annual Hypoxia in a Low Latitude Freshwater Reservoir in Kerala, India, Using the Small AUV Maya, E. Desa, R. Madhan, P. Maurya, G. Navelkar, A. Mascarenhas, S. Prabhudesai, S. Afzulpurkar, E. Desa, A. Pascoal, M. Nambiar (3) 60-70


Case Study: Skagerrak Wrecks and Measures to Reduce the Environmental Risk,C.M. Hansen, P.E. Hagen, P. Lågstad,J.A. Tørnes (4) 100-104

A Look Back at the MTS Journal of June 1990: “A Deepest Ocean Presence”, J. Jaeger, C. MacVean (5) 63-64

The Old Arguments of Manned Versus Unmanned Systems Are About to Become Irrelevant: New Technologies Are Game Changers, G. Hawkes (5) 164-168

Education and ResearchBiological /Chemical OceanographyUnmanned Autonomous Sailing: Current Status and Future Role in Sustained Ocean Observations, P.F. Rynne, K.D. vonEllenrieder (1) 21-30


ICCAT: Managing or Documenting? L.E. Straker (1) 117-126


The Use of the RUST Database to Inventory, Monitor, and Assess Risk from Undersea Threats, M.L. Overfield, L.C. Symons (4) 33-40


Overview of the Centers for Disease Control and Prevention’s Chemical Weapons Disposal Oversight Program, T. Tincher (4) 132-138

Living Deep: A Synopsis of Hadal Trench Ecology, L.E. Blankenship-Williams, L.A. Levin (5) 137-143

Marine ArchaeologyAncient Shipwreck Survey and the Modern Submarine Landscape off Yalikavak, Turkey, M.L. Brennan (1) 47-49



Marine EducationDiving to the Deep: Uncovering theMysteries of Mid-Ocean Ridges, I.D. Jasper, A. Ramsey (1) 31-36

ROV Pontus, J. Bragg, L. Brockerville,T. Brown, C. Button, S. Crewe, G. Doyle,M. Flynn, M. Follett, S. Follett, M. Freeman, A. Furneaux, J. Higdon, N. Hillier,D. Hornell, J. Howse, A. Lewis, P. MacNeil, M. Minay-Goldring, C. Neville, J. Pennell, W. Picco, R. Quick, D. Walsh, E. Waterman, J. Watson (1) 37-46

The NOAA Ship Okeanos Explorer: Continu-ing to Unfold the President’s Panel on Ocean Exploration Recommendation for Ocean Literacy, P. Keener-Chavis, L. Hotaling, S. Haynes (2) 73-80

MATE ROV Competitions: Using Under-water Robots as the Vehicle to Help Students Develop Science, Technology, Engineering, and Math Skills, J. Zande, C. Brown(3) 83-84

ROV Viking SPEAR, I. Jasper, R. Casaine,S. Cook, N. Grefe, B. Hutchinson,A. Ramsey, F. Unlu, A. Walsh, H. Williams, S. Fraser (3) 85-97

ROV 水神 (Suijin), B. Morrison, A. Maillet, M. Brown, L. Holloway, J. Moss, L. Holloway, D. Howse, M. White, S. Oldford, J. Young, M. Chaffey, S. Collins, M. Coles, B. Penney, G. Diamond (3) 98-109

Munitions Discarded at Sea, A.D. Davis IV (4) 11-13

HADEEP: Free-Falling Landers to theDeepest Places on Earth, A.J. Jamieson,T. Fujii, M. Solan, I.G. Priede (5) 151-160

Modeling the Trieste to Explore Densityand Buoyant Force, M. Sniffen, M. Hardy(5) 187-193

Marine EngineeringSeaWASP: A Small Waterplane Area Twin Hull Autonomous Platform for Shallow Water Mapping, E. Beck, W. Kirkwood, D. Caress, T. Berk, P. Mahacek, K. Brashem, J. Acain, V. Reddy, C. Kitts, J. Skutnik, G. Wheat(1) 6-12

Diving to the Deep: Uncovering theMysteries of Mid-Ocean Ridges, I.D. Jasper, A. Ramsey (1) 31-36

Demonstration of a New Technologyfor Restoration of Red Mangrove (Rhizophora mangle) in High-Energy Environments,J. Krumholz, C. Jadot (1) 64-72


Multi-Objective Optimization of an Autono-mous Underwater Vehicle, M. Martz, W.L. Neu (2) 48-60

Design Requirements for Autonomous Multi-vehicle Surface-Underwater Operations, B.S. Bingham, E.F. Prechtl, R.A. Wilson (2) 61-72

The NOAA Ship Okeanos Explorer: Continu-ing to Unfold the President’s Panel on Ocean Exploration Recommendation for Ocean Literacy, P. Keener-Chavis, L. Hotaling,S. Haynes (2) 73-80

Joint Description Methods of Wind and Waves for the Design of Offshore Wind Tur-bines, K.E. Mittendorf (3) 23-33

Application of Multiple Attribute Decision-Making (MADM) and Analytical Hierarchy Process (AHP) Methods in the Selection Deci-sions for a Container Yard Operating System, M.K. Moghadam, S. Bonsall, J. Wang, A. Wall (3) 34-50

An Empirical Study on Port Choice Behaviors of Shippers in a Multiple-Port Region, C.-C. Chou (3) 71-77

MATE ROV Competitions: Using Underwa-ter Robots as the Vehicle to Help StudentsDevelop Science, Technology, Engineering, and Math Skills, J. Zande, C. Brown(3) 83-84

A Global Prospective On Underwater Muni-tions, T.P. Long (4) 5-10

Historic Disposal of Munitions in U.S. and European Coastal Waters, How Historic Infor-mation Can be Used in Characterizing and Managing Risk, G. Carton, A. Jagusiewicz(4) 16-32


Overview of the Centers for Disease Control and Prevention’s Chemical Weapons Disposal Oversight Program, T. Tincher (4) 132-138

Pressure Testing: Best Practices, K. Hardy, M. James (5) 123-127


Deep Sound: A Free-Falling Sensor Platform for Depth-Profiling Ambient Noise in the Deep Ocean, D.R. Barclay, F. Simonet, M.J. Buckingham (5) 144-150

Marine Geodetic Information SystemsShallow Water Surveying Using Experimental Interferometric Synthetic Aperture Sonar, S.R. Silva, S. Cunha, A. Matos, N. Cruz(1) 50-63

Marine MaterialsDemonstration of a New Technology for Restoration of Red Mangrove(Rhizophora mangle) in High-Energy Envi-ronments, J. Krumholz, C. Jadot (1) 64-72


Tethered and Untethered Vehicles: TheFuture Is in the Past, J.R. McFarlane(2) 9-12


Multi-Objective Optimization of an Autono-mous Underwater Vehicle, M. Martz, W.L. Neu (2) 48-60

Insights into Habitat Utilization by Green Turtles (Chelonia mydas) During the Inter-Nesting Period Using Animal-Borne Digital Cameras, W.J. Fuller, A.C. Broderick, S.K. Hooker, M.J. Witt, B.J. Godley (3) 51–59

The Broader Basis for Investing in Munitions Assessment and Removal, D.J. Basta(4) 14-15

Historic Disposal of Munitions in U.S. and European Coastal Waters, How Historic Information Can be Used in Characterizing and Managing Risk, G. Carton, A. Jagusiewicz(4) 16-32

The Use of the RUST Database to Inventory, Monitor, and Assess Risk from Undersea Threats, M.L. Overfield, L.C. Symons (4) 33-40

Detection, Recovery, and Destruction System for Sea-Disposed Chemical Munitions: Port Kanda, Japan, J.K. Asahina, H. Shimoyama, K. Hayashi, A. Shinkai (4) 116-126

Munitions and Dredging Experience on the United States Coast, P. Greene, G. Follett, C. Henker (4) 127-131

Human Exploration of the Deep Seas: Fifty Years and the Inspiration Continues, W. Kohnen (5) 42-62

Ocean ExplorationROV Pontus, J. Bragg, L. Brockerville,T. Brown, C. Button, S. Crewe, G. Doyle,M. Flynn, M. Follett, S. Follett, M. Freeman,A. Furneaux, J. Higdon, N. Hillier, D. Hornell, J. Howse, A. Lewis, P. MacNeil, M. Minay-Goldring, C. Neville, J. Pennell, W. Picco, R. Quick, D. Walsh, E. Waterman, J. Watson (1) 37-46





The NOAA Ship Okeanos Explorer: Continuing to Unfold the President’s Panel on Ocean Exploration Recommendation for Ocean Literacy, P. Keener-Chavis, L. Hotaling, S. Haynes (2) 73-80

MATE ROV Competitions: Using Under-water Robots as the Vehicle to Help Students Develop Science, Technology, Engineer-ing, and Math Skills, J. Zande, C. Brown (3) 83-84

How Deep Is Deep?, B.J. Rosenthal (5) 8

U.S. Navy Involvement With DSV Trieste, C.B. Bishop (5) 15

Meanwhile, Back on the Surface: Further Notes on the Sounding of Trenches, R.L. Fisher (5) 16-19

In the Trenches... Topside Remembrances by the Chief of the Boat, DSV Trieste, J. Michel (5) 20-22

Human Exploration of the Deep Seas: Fifty Years and the Inspiration Continues, W. Kohnen (5) 42-63

Project Deepsearch: An Innovative Solution for Accessing the Oceans, L. Taylor, T.Lawson (5) 169-177

Physical Oceanography/MeteorologyPeriodic Behavior of the Bubble Jet (Geyser) in the Taketomi Submarine Hot Springs of the Southern Part of Yaeyama Archipelago, Japan, Y. Furushima, M. Nagao, A. Suzuki, H. Yamamoto, T. Maruyama (3) 13-22

Experiments with Broadband Sonar for the Detection and Identification of Endangered Shortnose Sturgeon, H.M. Brundage III,J-B. Jung (3) 78-82

Site Assessment and Risk ManagementFramework for Underwater Munitions,S. Sayle, T. Windeyer, M. Charles, S. Conrod, M. Stephenson (4) 41-51

Discarded Military Munitions Case Study: Ordnance Reef (HI-06), Hawaii, S.S.Garcia, K. MacDonald, E.H. De Carlo, M.L. Overfield, T. Reyer, J. Rolfe (4) 85-99

Journey to the Challenger Deep: 50 Years Later With the Nereus Hybrid Remotely Operated Vehicle, B. Fletcher, A. Bowen,D.R. Yoerger, L.L. Whitcomb (5) 65-76

Remote SensingShallow Water Surveying Using Experimental Interferometric Synthetic Aperture Sonar, S.R. Silva, S. Cunha, A. Matos, N. Cruz (1) 50-63



Site Assessment and Risk ManagementFramework for Underwater Munitions,S. Sayle, T. Windeyer, M. Charles, S. Conrod, M. Stephenson (4) 41-51

AUV Sensors for Real-Time Detection,Localization, Characterization, and Monitor-ing of Underwater Munitions, R. Camilli, B.S. Bingham, M.V. Jakuba, A.N. Duryea,R. LeBouvier, M. Dock (4) 76-84



Government and Public AffairsMarine Law and PolicyUnmanned Autonomous Sailing: Current Status and Future Role in Sustained Ocean Observations, P.F. Rynne, K.D. von Ellenrieder (1) 21-30


ICCAT: Managing or Documenting?, L.E. Straker (1) 117-126

Historic Disposal of Munitions in U.S. and European Coastal Waters, How Historic Information Can be Used in Character-izing and Managing Risk, G. Carton, A. Jagusiewicz (4) 16-32

Charting a Course for the Marianas Trench Marine National Monument, M. Tosatto (5) 161-163

Marine Mineral ResourcesThe Underwater Cultural Heritage and Marine Scientifi c Research in the Exclusive Economic Zone K.L. Croff (1) 93-100

Marine SecurityCluster Space Control of AutonomousSurface Vessels Paul Mahacek, Ignacio Mas,O. Petrovic, J. Acain, C. Kitts (1) 13-20

ROV Pontus J. Bragg, L. Brockerville,T. Brown, C. Button, S. Crewe, G. Doyle, M. Flynn, M. Follett, S. Follett, M. Freeman,A. Furneaux, J. Higdon, N. Hillier, D. Hornell, J. Howse, A. Lewis, P. MacNeil, M. Minay-Goldring, C. Neville, J. Pennell, W. Picco, R. Quick, D. Walsh, E. Waterman, J. Watson (1) 37-46

Shallow Water Surveying Using Experimental Interferometric Synthetic Aperture SonarS.R. Silva, S. Cunha, A. Matos, N. Cruz(1) 50-63

Ocean Economic PotentialSeaWASP: A Small Waterplane Area Twin Hull Autonomous Platform for ShallowWater Mapping E. Beck, W. Kirkwood,D. Caress, T. Berk, P. Mahacek, K. Brashem, J. Acain, V. Reddy, C. Kitts, J. Skutnik,G. Wheat (1) 6-12

Ocean Observing SystemsUnmanned Autonomous Sailing: Current Status and Future Role in Sustained Ocean Observations, P.F. Rynne, K.D. von Ellenrieder (1) 21-30

The Use of the RUST Database to Inven-tory, Monitor, and Assess Risk from Undersea Threats, M.L. Overfield, L.C. Symons(4) 33-40

Ocean PollutionDemonstration of a New Technology for Restoration of Red Mangrove (Rhizophora mangle) in High-Energy Environments,J. Krumholz, C. Jadot (1) 64-72


A Global Prospective On Underwater Muni-tions, T.P. Long (4) 5-10

Munitions Discarded at Sea, A.D. Davis IV (4) 11-13

The Broader Basis for Investing in Munitions Assessment and Removal, D.J. Basta(4) 14-15

Historic Disposal of Munitions in U.S. and European Coastal Waters, How HistoricInformation Can be Used in Character-izing and Managing Risk, G. Carton, A. Jagusiewicz (4) 16-32

The Use of the RUST Database toInventory, Monitor, and Assess Risk from Undersea Threats, M.L. Overfield, L.C. Symons (4) 33-40

A Case Study in Modeling Dispersion of Yperite and CLARK I and II from Munitions at Paardenmarkt, Belgium, F. Francken, A.M. Hafez (4) 52-61

AUV Sensors for Real-Time Detection,Localization, Characterization, and Monitor-ing of Underwater Munitions, R. Camilli, B.S. Bingham, M.V. Jakuba, A.N. Duryea,R. LeBouvier, M. Dock (4) 76-84


CommentariesA Look Back at the MTS Journal of June 1990: “A Deepest Ocean Presence”, J. Jaeger, C. MacVean (5) 63-64

Charting a Course for the Marianas Trench Marine National Monument, M. Tosatto(5) 161-163

The Sea: A New Frontier, D.A. MacLean(5) 178-186

Trieste I Deepest Manned Dive Passes 35th Anniversary, A. Rechnitzer (5) 23-24


2009 Reviewers for MTS Journal Guy Ampleman DRDC ValcartierAnne Andrews SERDP and ESTCPKaren Arthur Smithsonian InstitutionTim Askew ConsultantM.A. Atmanand National Institute of Ocean

Technology, India Peter Auster University of ConnecticutBrian Bingham University of HawaiiJohn S. Bird Marport Canada Inc.Andy Bowen Woods Hole Oceanographic

InstitutionRichard Buckingham U.S. NavyIlya V. Buynevich Woods Hole Oceanographic

InstitutionMassimo Caccia CNR - ISSIAPaul Carroll U.S. NavyGeoffrey Carton CALIBRE SystemsPaulo Casale Universita La Sapienza Y-H Chen Chung Cheng UniversityJames Childress University of California, Santa

BarbaraRay Chiou Naval Facilities Engineering

Service CenterKathy Ciolfi U.S. ArmyNora Deans North Pacific Research Board

Zeki Demirbilek U.S. Army Corps of EngineersYong Deng Shanghai Transportation UniversityGerald Denny Applied Physics Laboratory,

University of WashingtonJohn Dinwoodie University of PlymouthPaul Dragos BatelleDean Edwards University of IdahoDon Eickstedt MITDan Eiser Blueberries on the Buffalo FarmJim Elliott U.S. Coast GuardRyan Eustice University of MichiganGordon Fader Atlantic Marine Geological

Consulting Ltd.Will Forman Submersible Designer, Builder,

and PilotThomas Fredette U.S. Army Corps of EngineersPaul Gendron Naval Research LaboratoryJoseph Germano Germano & AssociatesReza Ghorbani University of HawaiiPeter Girguis Harvard UniversitySteve Gittings NOAA’s Office of National Marine

SanctuariesAndrew Gooday University of SouthamptonMel Goodwin The Harmony Project,

Charleston, SC

Nuno Gracias University of GironaVivian Graham U.S. ArmyDale Green Teledyne Benthos, Inc.Hans Groen DRC AtlanticRainer Haas Büro für Altlastenerkundung

und UmweltforschungBurton Hamner Hydrovolts, Inc.Roy Edgar Hansen University of OsloJørgen Hansson Swedish Coast GuardIan Hartwell NOAAArkal Vittal Hedge National Institute of Technology,

Karnataka, IndiaMichael Heithaus Florida International UniversityBrett Hobson Monterey Bay Aquarium

Research InstituteMarc Hodges American Petroleum InstituteMary Hollinshead University of Rhode IslandJoe Hughes J. B. Hughes and AssociatesMichael Lazlo Incze Naval Undersea Warfare Center,

NewportAndrzej Jagusiewicz Environmental Protection, PolandCorey Jaskolski Hydro TechnologiesLawrence Juda University of Rhode IslandFred Klein Noblis


William Kirkwood Monterey Bay Aquarium

Research InstituteDonna Kocak Maritime Communication

Services, HARRIS CorporationMarc Koch Leuphana University of Luneburg,

GermanyAlfred Krippendorf Hazard Control GmbHFrancois Lauzon StantecKortney Leabourne Deep Ocean EngineeringRoy R. Lewis III Coastal Resources Group, Inc.Terrance Long Wentworth EnvironmentalMike MacDonald International Submarine

Engineering, Ltd.Melissa Madrigal NOAACatherine McClellan Duke University Marine

LaboratoryPhillip McGillivary U.S. Coast GuardPatrick McLaren GeoSea Consulting (Canada) Ltd.Ann-Marie Mueller Aquacoustics, Inc.

Timothy Mulligan Scientist Emeritus, Dept. of

Fisheries and Oceans, CanadaVincent Myers DRC AtlanticMasahiko Nakamura Kyushu UniversityHerb Nelson Office of the Secretary of DefenseWilliam Phoel Undersea Research Foundation

International, IncChris Roman University of Rhode IslandAbolfazl Saajedi Liverpool John Moores UniversityStephanie Showalter National Sea Grant Law CenterDavid Smallwood Northrop Grumman CorporationCharles (Mike) Staehle Submersible Systems Technology

ConsultantThomas Stock Dynasafe Germany GmbHHiroyoshi Suzuku Osaka UniversityChristian Tamburini Université de la Méditerranée -

Centre d’Océanologie de MarseillePaul Tyler University of Southampton

Lewis Thompson University of Texas at AustinRalf Trapp ConsultantTamaki Ura University of TokyoFrank Wabnitz FMC TechnologiesBarrie Walden Woods Hole Oceanographic

InstitutionDon Walsh International Maritime

IncorporatedJeffrey Waugh U.S. Army Corps of EngineersJ. Morgan Wells Former Director NOAA Diving

ProgramRoy Wilkens University of HawaiiStanislaw Witek Technology University of Wroclaw X. Xie University of ManchesterWerner Zielke University of HannoverRobert Wernli First Centurion Enterprises


BOA RD OF DIREC T ORSPresidentElizabeth CorbinHawaii, Department of Business, Economic Development and TourismPresident-electJerry BoatmanPlanning Systems, Inc.Immediate Past PresidentBruce C. Gilman, P.E.ConsultantVP—Section AffairsKevin HardyDeepSea Power and LightVP—Education and ResearchJill ZandeMATE CenterVP—Industry and TechnologyJerry C. WilsonFugro Pelagos, Inc.VP—PublicationsKarin LynnTreasurer and VP—Budget and FinanceDebra KillInternational Submarine EngineeringVP—Government and Public AffairsKaren KohanowichNURP

SEC T IONSCanadian MaritimeVacantFloridaProf. Mark LutherUniversity of South FloridaGulf CoastTed BennettNaval Oceanographic OfficeHampton RoadsRaymond TollSAICHawaiiPhilomene Verlaan, Ph.D., J.D.HoustonMarcy A. WhitesOil States Industries, Inc.JapanProf. Toshitsugu SakouTokai UniversityMontereyJill ZandeMATENew EnglandChris JakubiakUMASS Dartmouth-SMASTNewfoundland and LabradorVacantPuget SoundFritz StahrUniversity of WashingtonSan DiegoBarbara FletcherSSC-San DiegoSouth KoreaDr. Seok Won HongMaritime & Ocean Engineering Research Inst.(MOERI/KORDI)Washington, D.C.Robert (Rusty) MirickBooz Allen Hamilton

P ROF E S SION A L COMMI T T EE S

Industry and TechnologyBuoy TechnologyDr. Walter PaulWoods Hole Oceanographic InstitutionCables & ConnectorsVacantDeepwater Field Development TechnologyDr. Benton BaughRadoil, Inc.DivingDavid C. BerryOcean Projects/Exxon MobilDynamic PositioningHoward ShattoShatto EngineeringManned Underwater VehiclesWilliam KohnenSEAmagine Hydrospace CorporationMooringsVacantOceanographic InstrumentationDr. Jim IrishUniversity of New HampshireOffshore StructuresDr. Peter W. MarshallMHP Systems EngineeringRemotely Operated VehiclesDrew MichelROV Technologies, Inc.Renewable EnergyRich ChwaszczewskiRopes and Tension MembersEvan ZimmermanDelmar SystemsSeafloor EngineeringVacantUnderwater ImagingDr. Fraser DalgleishHarbor Branch Oceanographic InstituteUnmanned Maritime VehiclesJustin ManleyLiquid Robotics

Education and ResearchMarine ArchaeologyBrett PhaneufProMare, Inc.Marine EducationDr. Susan B. CookConsortium for Ocean LeadershipMarine Geodetic Information SystemsDave ZilkoskiNOAAMarine MaterialsVacantOcean ExplorationVacantPhysical Oceanography/MeteorologyDr. Richard L. CroutNational Data Buoy CenterRemote SensingHerb RipleyHyperspectral Imaging Limited

Government and Public AffairsMarine Law and PolicyCapt. Craig McLeanNOAAMarine Mineral ResourcesDr. John C. WiltshireUniversity of HawaiiMarine SecurityDallas MeggittSound & Sea TechnologyOcean Economic PotentialJames MarshUniversity of HawaiiOcean Observing SystemsDonna KocakMaritime Communication Systems,HARRIS CorporationOcean PollutionJacob SobinNOAA Coastal Services Center

S T UDEN T SEC T IONSDuke UniversityCounselor: Douglas Nowacek, Ph.D.Florida Atlantic UniversityCounselor: Douglas A. Briggs, Ph.D.Florida Institute of TechnologyCounselor: Stephen Wood, Ph.D., P.E.Long Beach City CollegeCounselor: Scott FraserMassachusetts Institute of TechnologyCounselor: Alexandra Techet, Ph.D.Monterey Peninsula CollegeCounselor: Jeremy R. HertzbergTexas A&M University—College StationCounselor: Patrick LynettTexas A&M University—GalvestonCounselor: Victoria Jones, Ph.D.University of HawaiiCounselor: Reza GhorbaniUniversity of Southern MississippiCounselor: Stephen Howden, Ph.D.

HONOR A RY MEMBERS†Robert B. Abel†Charles H. BussmannJohn C. Calhoun, Jr.John P. Craven†Paul M. FyeDavid S. Potter†Athelstan Spilhaus†E. C. Stephan†Allyn C. Vine†James H. Wakelin, Jr.†deceased

Marine Technology Society Officers

CORP OR AT E MEMBERSABCO Subsea Houston, TexasAllseas USA, Inc. Houston, TexasAMETEK Sea Connect Products, Inc. Westerly, Rhode IslandC & C Technologies, Inc. Lafayette, LouisianaC-MAR America, Inc. Houston, TexasCompass Publications, Inc. Arlington, VirginiaConverteam Houston, TexasCortland Cable Company Cortland, New YorkDeep Marine Technology, Inc. Houston, TexasDelcor USA Houston, TexasDOF Subsea USA Houston, TexasDynacon, Inc. Bryan, Texas E.H. Wachs Company Houston, TexasElectrochem Solutions, Inc. Clarence, New YorkFluor Corp. Sugar Land, TexasFugro Chance, Inc. Lafayette, LouisianaFugro-McClelland Marine Geosciences Houston, TexasFugro Pelagos, Inc. San Diego, CaliforniaGeospace Offshore Cables Houston, TexasGS-Hydro US Houston, TexasHydroid, LLC Pocasset, MassachusettsInnerspace Corporation Covina, CaliforniaINTEC Engineering Houston, TexasInterMoor, Inc. Houston, TexasiRobot Corporation Durham, North CarolinaJ P Kenny, Inc. Houston, TexasKongsberg Maritime, Inc. Houston, TexasL-3 Dynamic Positioning and Control Systems Houston, TexasL-3 MariPro Goleta, CaliforniaLockheed Martin Sippican Marion, MassachusettsMaritime Communication Services Melbourne, FloridaMitsui Engineering and Shipbuilding Co. Ltd. Tokyo, JapanMohr Engineering & Testing Houston, TexasOcean Design, Inc. Daytona Beach, FloridaOceaneering Advanced Technologies Hanover, MarylandOceaneering International, Inc. Houston, TexasOdyssey Marine Exploration Tampa, FloridaPegasus International, Inc. Houston, TexasPerry Slingsby Systems, Inc. Houston, TexasPhoenix International Holdings, Inc. Largo, Maryland

QinetiQ North America – Technology Solutions Group Reston, VirginiaS&J Diving, Inc. Houston, TexasSaipem America, Inc. Houston, TexasSchilling Robotics, LLC Davis, CaliforniaSEA CON Brantner and Associates, Inc. El Cajon, CaliforniaSonTek/YSI, Inc. San Diego, CaliforniaSouth Bay Cable Corp. Idyllwild, CaliforniaSubconn, Inc. Burwell, NebraskaSubsea 7 (US), LLC Houston, TexasTechnip Houston, TexasTeledyne RD Instruments, Inc. Poway, CaliforniaTyco Telecommunications (US), Inc. Morristown, New Jersey

BUSINE S S MEMBERSAanderaa Data Instruments, Inc. Attleboro, MassachusettsAntares Offshore, LLC Houston, TexasAshtead Technology, Inc. Houston, TexasBennex Subsea, Houston Houston, TexasBioSonics, Inc. Seattle, WashingtonC.A. Richards and Associates, Inc. Houston, TexasC-Innovation LLC Mandeville, LouisianaCochrane Technologies, Inc. Lafayette, LouisianaCompass Personnel Services, Inc. Katy, TexasDeepSea Power and Light San Diego, CaliforniaDeepwater Rental and Sypply New Iberia, LouisianaDOER Marine Alameda, CaliforniaEquipment and Technical Services, Inc. Houston, TexasFalmat, Inc. San Marcos, CaliforniaFibreMax Joure, NetherlandsFugro Atlantic Norfolk, VirginiaFugro Jacques GeoSurveys, Inc. St. John’s, Newfoundland and Labrador, CanadaFugro Seafloor Surveys, Inc. Seattle, WashingtonGilman Corporation Gilman, ConnecticutGlobal Industries Offshore, LLC Houston, TexasHawboldt Industries, Ltd. Chester, Nova Scotia, CanadaHorizon Marine, Inc. Marion, MassachusettsICAN Mt. Pearl, Newfoundland and Labrador, CanadaIntrepid Global, Inc. Houston, TexasIVS 3D Portsmouth, New Hampshire

IXSEA Woburn, MassachusettsLighthouse R&D Enterprises, Inc. Houston, TexasLiquid Robotics Palo Alto, CaliforniaMakai Ocean Engineering, Inc. Kailua, HawaiiMarine Desalination Systems, LLC St. Petersburg, FloridaMatthews-Daniel Company Houston, TexasNorth Pacific Crane Company Seattle, WashingtonOceanic Imaging Consultants, Inc. Honolulu, HawaiiOceanWorks International Houston, TexasQuest Offshore Resources Sugar Land, TexasRemote Ocean Systems, Inc. San Diego, CaliforniaRRC Robotica Submarina Macaé, BrazilSeaBotix San Diego, CaliforniaSES – Subsea Engineering Solutions, Inc. Houston, TexasSonardyne, Inc. Houston, TexasSound Ocean Systems, Inc. Redmond, WashingtonStress Subsea, Inc. Houston, TexasTechnology Systems Corporation Palm City, FloridaTeledyne Impulse San Diego, CaliforniaTension Member Technology Huntington Beach, CaliforniaVideoray, LLC Phoenixville, Pennsylvania

INS T I T U T ION A L MEMBERSCLS America, Inc. Largo, MarylandConsortium for Ocean Leadership Washington, DCHarbor Branch Oceanographic Institution, Inc. Fort Pierce, FloridaInternational Seabed Authority Kingston, JamaicaIranian Fisheries Research Organization Tehran, IranMarine Institute St. John’s, Newfoundland and Labrador, Canada MOERI/KORDI Library Dagjeon, KoreaMonterey Bay Aquarium Research Institute Moss Landing, CaliforniaNational Research Council Institute for Ocean Technology St. John’s, Newfoundland and Labrador, Canada Naval Facilities Engineering Service Center Port Hueneme, CaliforniaNOAA/PMEL Seattle, WashingtonNoblis Falls Church, VirginiaSociety of Ieodo Research Jeju-City, South KoreaUniversity of California Library Berkeley, California

Marine Technology Society Member Organizations

The Marine Technology Society gratefully acknowledges the critical support of the Corporate, Business, and Institutional members listed.Member organizations have aided the Society substantially in attaining its objectives since its inception in 1963.

The MTS Journal

includes technical

papers, notes and

commentaries

of general interest in

most issues.

Contact Managing EditorAmy Morgante

([email protected])

if you have material you

would like considered.

Specifications for

submitting a manuscript

are on the MTS Web site

under the Publications menu.

www.mtsociety.org

E-mail:

[email protected]

Or visit our homepage at

www.mtsociety.org

UPCOMING MTS JOURNAL ISSUES CALL FOR PAPERS

January/February 2010Marine Technology for Offshore Wind Power

March/April 2010Student-Authored Papers

May/June 2010Obstacles, Approaches and Opportunities: U.S. Sustainable Marine Aquaculture Development in the 21st CenturyGuest Editor: John Corbin, Aquaculture Planning & Advocacy LLC

July/August 2010Best of MTS Conferences

Check the Society Web site for future Journal topics.

www.mtsociety.org

Marine Technology Society Publications ListingThe following Marine Technology Society publications are available for purchase.Prices for 2009 are listed below.Members are granted a discount of 10% off the purchase order.You can purchase publications by doing one of the following:■ Calling MTS at 410-884-5330 with

your publication(s) order and credit card number. Reference 43.5.

■ Logging on to our Web site at www.mtsociety.org, selecting the Store.

■ Circling the items and filling out the form below, then mailing it to MTS.

JOURNALSThe Legacy of Underwater Munitions

Worldwide .................................................. $20Diving Deeper: Expanded Papers from Recent

MTS Conferences....................................... $20Student Authors: The Next Wave of Marine

Technology Professionals ............................ $20Global Lessons Learned from Regional Coastal

Ocean Observing Systems .......................... $20Offshore Wind Energy .................................... $20The State of Technology in 2008 .................... $20Advances in Animal-Borne Imaging ................ $20Societal Benefits of Marine Technology .............$20Stemming the Tide of Coastal Disasters, Part 2 .. $20Stemming the Tide of Coastal Disasters, Part 1 .. $20Tales of Not-So-Ancient Mariners: Review From

the MTS Archives ...................................... $20Promoting Lifelong Ocean Education ............. $20State of Technology: Marine Technology

in 2005........................................................$20Acoustic Tracking of Marine Fishes: Implications for

Design of Marine Protected Areas .................. $20Final Report from the U.S. Commission on Ocean

Policy: Implications and Opportunities ...... $20Underwater Pollution Threats to Our

Nation’s Marine Resources .......................... $20Innovations in Ocean Research Infrastructure to

Advance High Priority Science ................... $20Human-generated Ocean Sound and

the Effects on Marine Life .......................... $20Ocean Observing Systems ............................... $20

Science, Technology and Management in the National Marine Sanctuary Program .......... $20

Ocean Energy—an Overview of the State of the Art ........................................................ $20

Marine Archaeology and Technology—A New Direction in Deep Sea Exploration .... $20

Technology in Marine Biology ........................ $20Ocean Mapping—A Focus of Shallow

Water Environment .................................... $20Oceanographic Research Vessels ...................... $20Technology as a Driving Force in the Changing Roles

of Aquariums in the New Millennium .......... $20Submarine Telecoms Cable Installation

Technologies ............................................... $20Deep Ocean Frontiers ..................................... $20A Formula for Bycatch Reduction ................... $16Marine Science and Technology in the Asia Region,

Part 2 ......................................................... $16Marine Science and Technology in the Asia Region,

Part 1 ......................................................... $16Major U.S Oceanographic Research Programs:

Impacts, Legacies and the Future ............... $16Marine Animal Telemetry Tags: What We Learn and

How We Learn It ...........................................$16Scientific Sampling Systems for Underwater

Vehicles ...................................................... $16U.S. Naval Operational Oceanography ........... $16Innovation and Partnerships for Marine Science and

Technology in the 21st Century ...................$16Marine Science and Technology in Russia ....... $16Public-Private Partnerships For Marine Science &

Technology (1995) ..................................... $16Oceanographic Ships (1994–95) ..................... $16Military Assets for Environmental Research

(1993–94) .................................................. $16Oceanic and Atmospheric Nowcasting and

Forecasting (1992) ...................................... $12Education and Training in Ocean Engineering

(1992) ........................................................ $12Global Change, Part II (1991–92) .................. $10Global Change, Part 1 (1991) ......................... $10

MARINE EDUCATIONGuide to Marine Science and Technology Programs

In Higher Education (2008) ..................$25Operational Effectiveness of Unmanned

Underwater Systems ..............................$99State of Technology Report—Ocean and Coastal

Engineering (2001) ...............................$7 dom ..............................................................$9For.State of Technology Report—Marine Policy and

Education (2002) ..................................$7 dom ..............................................................$9 For.

PROCEEDINGSOceans 2008 MTS/IEEE (CDROM) ............. $80Oceans 2007 MTS/IEEE (CDROM) ............. $80Oceans 2006 MTS/IEEE (CDROM) ............. $80Oceans 2005 MTS/IEEE (CDROM) ............. $50Oceans 2004 MTS/IEEE (CDROM) ............. $50Oceans 2003 MTS/IEEE (CDROM) ............. $50Oceans 2002 MTS/IEEE (CDROM) ............. $50Oceans 2001 MTS/IEEE (CDROM) ............. $50Artificial Reef Conference ............................... $25Oceans 2000 MTS/IEEE CD-ROM .............. $50Oceans 1999 MTS/IEEE ‘99 Paper Copy ....... $80Oceans 1999 MTS/IEEE CDROM ................ $40Ocean Community Conference ‘98 .............. $100Underwater Intervention 2002 ........................ $50Underwater Intervention 2000 ........................ $50Underwater Intervention ‘99 ........................... $50Underwater Intervention ‘98 ........................... $50500 Years of Ocean Exploration

(Oceans ‘97) ............................................. $130Underwater Intervention ‘97 ........................... $50The Coastal Ocean—Prospects for

The 21st Century (Oceans ‘96) ................ $145Underwater Intervention ‘96 ........................... $50Challenges of Our Changing Global

Environment (Oceans ‘95) ....................... $145Underwater Intervention ‘95 ........................... $75Underwater Intervention ‘94 ........................... $95Underwater Intervention ‘93 ........................... $95MTS ‘92 ....................................................... $140ROV ‘92 ....................................................... $105MTS ‘91 ....................................................... $130ROV ‘91 ......................................................... $951991–1992 Review of Developments in Marine Living

Resources, Engineering and Technology ...........$15ROV ‘90 ......................................................... $90The Global Ocean (Oceans ‘89) ..................... $75ROV ‘89 ......................................................... $65Partnership of Marine Interest (Oceans ‘88) ... $65The Oceans–An International Workplace

(Oceans ‘87) ............................................... $65Organotin Symposium (Oceans ‘87, Vol. 4) ... $10ROV ‘87 ......................................................... $40Technology Update–An International

Perspective (ROV ‘85) ................................ $35Ocean Engineering and the Environment

(Oceans ‘85) ............................................... $45Ocean Data: Sensor-to-User (1985) ................ $33

S E N D O R D E R F O R M T O :

Marine Technology Society5565 Sterrett PlaceSuite 108Columbia, Maryland 21044FAX: (410) 884-9060

Please call MTS at 410-884-5330 for anMTS Membership Application or see the following pages for an Application.

M T S P U B L I C A T I O N S O R D E R F O R M – R E F : 4 3 . 5Please print

Mr./Ms./Dr. First name Last name

Address

City State Zip Country

Telephone FAX

E-mail

P A Y M E N T: Make checks payable to Marine Technology Society (U.S. funds only)Credit card: ❏ Amex ❏ Mastercard ❏ Visa ❏ Diners Club

Card Number Exp. Date Signature

Underwater Intervention 2010February 9–11, 2010 New Orleans, La. www.underwaterintervention.com

More than 145 booths are already sold, and there are numerous sponsorship opportunities available. Visit the website to find out how to add your company’s name.

ONR/MTS Buoy WorkshopMarch 9–11, 2010 Monterey, Calif.www.whoi.edu/buoyworkshop/index.html

The 8th Buoy Workshop will be held at the Monterey Conference Center, but come a day early to enjoy an icebreaker reception at the lodging headquarters, The Hotel Pacific, located across the street from the Conference Center. Over the course of the 2.5 days workshop, presentations will cover many of the aspects of the highly specialized technology and field of oceanographic and other data buoy systems. The buoy group has become quite international, with many applications and projects from the Great Lakes to the coastal and deep oceans around the world.

Offshore Technology ConferenceMay 3–6, 2010Houston, Texaswww.otcnet.org/2010

The submission deadline to have your technology recognized in the Spotlight on New Technology Awards is January 15. MTS members have won in the past, so don’t miss this opportunity!

For exhibitors, changes have been made regarding the available indoor exhibition space, which will streamline access to exhibits and enhance the tradeshow experience for both attendees and exhibitors. For attendees, housing information should be available now, and registration information will be available by the end of January 2010.

OCEANS’10 MTS/IEEE Seattle Innerspace: A Global ResponsibilitySeptember 20–23, 2010Seattle, Washingtonwww.oceans10mtsieeeseattle.org

Seattle’s OCEANS’10 features tutorials on special-interest topics, a comprehensive technical program of lectures and presentations, a student program, and a large exhibit hall with products from over 100 companies. For more information, e-mail [email protected].

rolex oyster perpetual and deepsea are trademarks.

oyster perpetualrolex deepsea

rolex is proud to honor the trieste &

don walsh on the 50th anniversary

STOP...and consider your options.Teledyne RDI’s Explorer DVL is now available in the traditional remote configuration or our new self-contained configuration.

Options...Teledyne RD Instruments’ new self-contained Explorer DVL provides you with yet another

valuable alternative for your littoral underwater navigation needs. Now, in addition to our

remote head Explorer, the self-contained configuration offers you all of Teledyne RDI’s proven

Broadband technology packed into a single housing for “power-and-go” applications.

The self-contained unit also boasts a new phased array transducer, offering reduced size

and weight, plus enhanced system performance. The unit is rated to 500m for your littoral

navigation needs. Learn more at: www.rdinstruments.com/explorer.html

Speaking of options—Teledyne RDI has a full line of underwater Doppler products for your full spectrum of navigation needs.

Poway, CA USATel. +1-858-842-2600www.rdinstruments.com

www.sidus-solutions.com - (866) 978-1276

We are ready for highly hazardous locations and extreme conditions.

SIDUS is ready to deliver the capability to observe your target as if you were

right there, regardless of the elements!

For outstanding security, safety, asset and facility management, we've

put eyes exactly where you need them. ● Insustry Experience● Field Service Ready● Innovative Engineering● Installation Support

Sidus Honors the Trieste

In commemoration of the great achievements of people on whose shoulders we stand. This is a re-print from an advertisement by LAMB Co. in 1973 and framed in of ces for 37 years. Its presence today is a re-af rmation that the spirit lives on through the next generations.

The contrast between ordinary and great living is the difference between what a person is required to do to exist and what he/she feels they can and must do to be their best self. There are parasites in every society. They rely on the efforts and support of others. The margin of life is the difference between what they are and what they might become if they used their potential abilities.

There is a margin in the business world. In every industry and profession there are those who get by with a minimum of effort. They are more interested in money than in service; more concerned about what they can get than what they can give. They are specialists in mediocrity.

Others nd work an adventure. They want their product, or their service, to meet the highest standards. They nd satisfaction in being part of a team which produces something to enrich life. They strive to make their contribution as nearly perfect as possible. They put something extra into their work.

That attitude constitutes the margin in life.

There is also a margin in personal relationships. Sometimes we make friends reluctantly. We use people for our own ends. We are critical of those who threaten our positions. We make little effort to understand the point of view of those about us. We assume an air of superiority to hide our inner fears.

On the other hand, sometimes we reach out to people.

We are not blind to their weakness, but we recognize that there is value in every person. We look for the best. We see every individual as made in the divine image. We search for opportunities to relate to persons.

That attitude constitutes the margin of life.

There is a margin, too, in the realm of character. You have met those who assert that standards of value no longer exist. They believe there is no right and no wrong. Or they declare: “That is right which gives me pleasure, and that is wrong which limits my freedom.”

Concerned people recognize a standard of values. It is steeped in the heritage of the ages. It has been tested in the crucible of human experience. These men and women know that a code of laws must be adapted to each new generation, but they af rm the enduring importance of duty, honesty, and work.

That attitude constitutes the margin of life.

There is another margin in our relationship to society. It is tempting to ignore the call of responsibility – to blame someone else for pollution, or political corruption, or crime.

For a large number of those who are concerned, service is the plus element which helps to make a better world. They expand their horizons by giving their money, time, and efforts to lift the load of poverty, injustice, or hate. It isn’t what they have to do, but what they want to do in order to be their best.

That’s what makes the margin in life.

(2009) Claremont, California USA — www.seamagine.com

The Marine Technology Society is where opportunity runs deep. Our extensive offering of professional development and networking ensures the field of marine technology and our members’ careers con nue to rise.

Visit mtsociety.org to explore your membership benefits. Not a member? Join online today.

mtsociety.org

o

o

o

o

Marine Technology Society5565 Sterrett Place, Suite 108Columbia, Maryland 21044

Postage for periodicalsis paid at Columbia, MD,and additional mailing offices.

paper under high pressure: spherical glass flotation and

Documents