a once and future gulf of mexico ecosystem

8/4/2019 A Once and Future Gulf of Mexico Ecosystem

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A O ce a d FutureGul o MexicoEcosystemRestoratio Recomme datio so a Expert Worki g Group

Charles H. Peterso

Felicia C. Colema , Jeremy B.C. Jackso , R. Euge e Tur er, Gilbert T. Rowe

Richard T. Barber, Kare A. Bjor dal, Robert S. Car ey,Robert K. Cowe , Jo atha M. Hoekstra, James T. Hollibaugh,Shirley B. Laska, Richard A. Luettich Jr., Craig W. Ose berg,Stephe E. Roady, Sta ley Se er, Joh M. Teal a d Pi g Wa g


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Pete Peterson wishes to thank his co-authors, in particular Gene Turner, Felicia Coleman,Gil Rowe and Jeremy Jackson, or their insights and assistance in producing this report.The authors thank the Pew Environment Group or nancial support or this project and thethree peer reviewers, whose comments helped to improve the manuscript. We appreciatethe many help ul discussions that we each had with interested colleagues.

Acknowledgments

The views expressed are those o theauthors and do not necessarily refect theviews o the Pew Environment Group,Campaign or Healthy Oceans or The

Pew Charitable Trusts.

Suggested citation:Peterson, C. H.et al. 2011. A Onceand Future Gul o Mexico Ecosystem:Restoration Recommendations o anExpert Working Group. Pew EnvironmentGroup. Washington, DC. 112 pp.


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A Once and Future Gul o Mexico EcosystemRestoratio Recomme datio s o a Expert Worki g Group

Contents

The Pew Environment Group is the conservation arm o The Pew Charitable Trusts,a nongovernment organization that works globally to establish pragmatic, science-basedpolicies that protect our oceans, preserve our wildlands and promote clean energy.

www.PewEnvironment.org

3 Abstract

5 I troductio

9 Precede ts a d Pri ciples or Restori gthe Gul o Mexico Ecosystem

15 Acute a d Chro ic Stressors o the Gulo Mexico Be ore a d A ter the DWH Oil Spill

37 Recomme datio s or Resilie t Restoratioo the Gul o Mexico

91 Co clusio

93 Appendices

100 Endnotes

101 Re erences


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2 A O ce a d Future Gul o Mexico Ecosystem

A Padre Island National Seashore, TX

B Galveston, TX

C Flower Garden BanksNational Marine Sanctuary

D Grand Isle, LA

E Chandeleur Islands, LA(Breton National Wildli e Re uge)

F Pascagoula River, LA

G Green Canyon area(near the DWH spill site)

H De Soto Canyon

I Big Bend coastal region, FL, includesApalachicola Bay, St. Joe Bay and theFenholloway, Suwanee and OchlockoneeRivers

J Florida Keys National Marine Sanctuary

K Everglades National Park

Figure 1

The Gul o Mexico RegionFeatured sites mentioned in the report

CorpusChristi

PadreIsland

EgmontKey NationalWildli e Re uge

G

J

K

E

F

B

C

AMiami

GULF OF MEXICO

Mississippi

New Orleans

Baton Rouge

Houma

Biloxi

Mobile Pensacola

See map detail Page 28

See map detail Page 31

H

Galveston

Houston

TampaSite oDWH spill

D

I


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A O ce a d Future Gul o Mexico Ecosystem 3

The Deepwater Horizon (DWH) well blow-out released more petroleum hydrocarbonsinto the marine environment than anyprevious U.S. oil spill (4.9 million barrels),

ouling marine li e, damaging deep sea andshoreline habitats and causing closures oeconomically valuable sheries in the Gulo Mexico. A suite o pollutants liquidand gaseous petroleum compounds pluschemical dispersants poured into eco-systems that had already been stressed byover shing, development and global climatechange. Beyond the direct e ects that werecaptured in dramatic photographs o oiledbirds in the media, it is likely that there aresubtle, delayed, indirect and potentially syn-

ergistic impacts o these widely dispersed,highly bioavailable and toxic hydrocarbonsand chemical dispersants on marine li e

rom pelicans to salt marsh grasses and todeep-sea animals.

As tragic as the DWH blowout was, it hasstimulated public interest in protecting thiseconomically, socially and environmentallycritical region. The 2010 Mabus Report,commissioned by President Barack Obamaand written by the secretary o the Navy,provides a blueprint or restoring the Gulthat is bold, visionary and strategic. It isclear that we need not only to repair thedamage le t behind by the oil but also togo well beyond that to restore the anthro-pogenically stressed and declining Gulecosystems to prosperity-sustaining levelso historic productivity. For this report, weassembled a team o leading scientists withexpertise in coastal and marine ecosystemsand with experience in their restoration toidenti y strategies and speci c actions thatwill revitalize and sustain the Gul coastaleconomy.

Because the DWH spill intervened in eco-systems that are intimately interconnectedand already under stress, and will remainstressed rom global climate change, we

argue that restoration o the Gul must gobeyond the traditional in-place, in-kindrestoration approach that targets speci cdamaged habitats or species. A sustainable

restoration o the Gul o Mexico a terDWH must:

1. Recognize that ecosystem resilience hasbeen compromised by multiple humaninterventions predating the DWH spill;

2. Acknowledge that signi cant utureenvironmental change is inevitable andmust be actored into restoration plansand actions or them to be durable;

3. Treat the Gul as a complex and inter-connected network o ecosystems romshoreline to deep sea; and

4. Recognize that human and ecosystemproductivity in the Gul are interdepen-dent, and that human needs rom ande ects on the Gul must be integral torestoration planning.

With these principles in mind, we providethe scienti c basis or a sustainable restora-tion program along three themes:

1. Assess and repair damage rom DWHand other stresses on the Gul ;

2. Protect existing habitats andpopulations; and

3. Integrate sustainable human usewith ecological processes in the Gulo Mexico.

Under these themes, 15 historicallyin ormed, adaptive, ecosystem-basedrestoration actions are presented to recoverGul resources and rebuild the resilience o

its ecosystem. The vision that guides ourrecommendations undamentally imbedsthe restoration actions within the context othe changing environment so as to achieveresilience o resources, human communitiesand the economy into the inde nite uture.

Abstract


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On April 20, 2010, the eyes o the nationand the world ocused on the northern Gulo Mexico and witnessed the beginning o a

human and natural disaster. On that day, aBP oil well blew out on the MacondoProspect 1,500 m below the oceans sur aceand began gushing crude oil into thesea. Eleven men died rom the explosionsaccompanying the blowout and subsequent

re on the drilling rig, Deepwater Horizon.The great depth o the wellalmost a milebeneath the oceans sur acecomplicatede orts to stanch the torrential fow o oiland natural gas. During the next 85 days,an estimated 4.9 million barrels o crude oil

fowed into the sea as BP and the U.S. gov-ernment tried chemicals, concrete, physicalmaterial and other desperate measuresto plug the wellhead. The environmentaltragedy was dramatized in a continuous,mesmerizing video stream o the turbulentfow o oil and gas at the seafoor wellheadand in the satellite and television imageryo oil covering the sea sur ace, seabirds andshorelines. This blowout and spill releasedmore oil into U.S. waters than any other spillin history. In terms o human wel are, this

single event severely damaged the Gul snatural resources, harming the economy andcosting lives and jobs in a region dependenton shing, tourism and oil-and-gas extraction.

This tragedy, however, is but one o manyenvironmental perturbations that havedegraded or are still degrading the Gulenvironment. Over the previous ve yearsalone, or example, hurricanes Katrina, Ritaand Ike struck the Louisiana, Mississippi andTexas coasts, causing extensive loss o li eand property. Chronic stressors on the Gul

ecosystem include over shing and overhar-vesting o marine li e; pollution rom agri-cultural runo and industry; global climate

change and rising sea level; and alterationso terrain and rivers or oil exploration andreal estate development. Coastal marshacreage, riparian wetlands, and orestsin the drainage basins o the Mississippiand smaller rivers have declined dramati-cally, reducing sh and wildli e habitat andremoving natural water-puri ying unc-tions. These changes, in turn, have reducedthe Gul ecosystems ability to provide theservices and resources on which coastalcommunities depend.

The success and durability o actions takento restore damage caused by the oil releasewill depend upon the way Gul restorationaddresses the impacts o historical ecosys-tem degradation and anticipates uturechanges by creating both social and naturalresilience. Even narrowly ocused restorationactions are unlikely to be sustainable i they

ail to consider the complex and intercon-nected human and natural ecosystem o theGul . Restoration plans must also compen-sate or prior impacts to individual resourcesand to human economic enterprises andmust consider the ull scope o relationshipsto historical baseline conditions. Finally,the ability o restoration plans to anticipate

uture dynamic change will determine thesuccess o those plans over the long term.Some o these environmental changes, suchas sea level rise and severe weather events,are occurring aster and having largerconsequences along the Gul Coast thananywhere else in the country. There ore, theGul ecosystem could be a model or how

Introduction

The blowout and spillreleased more oil into U.S.

waters than any other oilspill incident in history.This tragedy, however, isbut one o many historic,recent and ongoingstresses degrading theGul environment.

Oil burns during a controlledre a ter the Gul oil spill.

Photo: Justin Stumberg/U.S.Navy/Marine Photobank


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to solve multiple social and natural chal-lenges to achieve sustainability in the aceo dramatic environmental change.

To assess restoration opportunities in theGul , we assembled a team o leadingscientists with expertise and experience incoastal and marine ecosystems and theirrestoration. Together we identi y strategies

and speci c actions that will help revitalizethe Gul Coast ecosystem and economy.Our scienti c approach is based upon spa-tially explicit and ecosystem-based insightsderived by in erring the baseline conditionsand controlling unctions o the Gul coastalecosystem as they were be ore majorhuman modi cations were made. Previoususe o this approach to guide ecologicalrestorations o estuarine (Lotzeet al. 2006),marine (Jacksonet al. 2001) and reshwater(Sche eret al. 2001) aquatic ecosystems

have revealed how human-induced modi -cations, such as over shing apex predatorsand historically dominant lter eeders,have led to the loss o ecosystem resiliencewhen subsequent perturbations occurred,such as nutrient overloading. Such interac-tions among multiple stressors can propelthe ecosystem across a threshold and intoan alternative persistent state rom whichrecovery to baseline conditions is di cult.For example, the overharvest o suspension-

eeding oysters rom Chesapeake Bay and

Pamlico Sound estuaries in the decadesaround 1900 disabled the capacity o theecosystem to exert top-down grazingcontrols on phytoplankton blooms. Whennutrient overloading occurred decades later,the suspension- eeders were no longer

unctionally capable o grazing downthe microalgae and helping to suppressbloom development (Jacksonet al. 2001).There ore, our restoration recommenda-tions address a range o modi cationsto the Gul ecosystem. Using historical

baselines to guide restoration does notmean that we advocate the impossible,such as rebuilding coastlines to match thelocations and elevations o previous timesbe ore substantial subsidence occurred.Instead, historical ecology guides us towardrestoring previously critical processes thatserve to organize the ecosystem and trig-ger compensatory internal dynamics thatstrengthen resilience.

The DWH well blowout is an obvious trag-edy, but it appears to have made at least

two positive contributions to the region.The publicity generated by the oil spill put aspotlight on the immense value o the natu-ral resources and communities o the GulCoast. It also drew attention to how littlepublic or private investment has been madein restoring the Gul ecosystem a ter pastinjuries or in creating the natural and socialresiliency required or this unique region tosustain itsel in the ace o a dramaticallychanging natural environment. Althoughgovernment promises o unding or hur-ricane rehabilitation and restoration haveproved overly optimistic, unds or Gul res-toration derived rom environmental nes

or ocean pollution and natural resourcedamage will be more substantial. Some othe unds are restricted to direct compensa-tion or damage done by the DWH oil spillto the Gul ecosystem, its natural resourcesand the Gul coastal economy; however,the potential uses or the rest o the undsrange broadly.

The ederal Oil Pollution Act o 1990(OPA) dictates criteria or compensatoryrestoration projects that can be supportedby monies given in settlement o naturalresource damage claims or awarded by thecourt system. OPA then has general jurisdic-tion over Gul restoration unds derived

rom legal settlements with BP. Under theprovisions o OPA, compensatory restora-

tion projects must be explicitly tied to thenatural resource injuries, either damage tospeci c resources, such as the loggerheadturtle, or damages to speci c habitats, suchas coastal marsh. Consequently, restora-tion that draws upon this source o undingmust be justi ed by linkage to one or moreinjured resources or habitats, such as thoselisted in Table 1.

The Gul ecosystem has been bu eted andso deeply modi ed by such a wide varietyo anthropogenic and natural stressors thatmerely ollowing traditional governmentguidelines or in-place, in-kind com-pensatory restoration under OPA or otherstatutes is unlikely to provide sustainablebene ts. For example, the combination osubsidence, global sea level rise, shorelineerosion by major hurricanes, and ero-sion and fooding acilitated by numerousnavigation channels cut through the wet-lands could easily lead to submersion anddrowning o Spartina marsh constructedat most or all sites where the DWH oil spill

The ability o restorationplans to anticipate

uture dynamic changewill determine thesuccess o those plansover the long term.

1900 Overharvesting o oystersrom the Chesapeake Bay and

other estuaries contributedto dramatic changes in theirecosystems. Above, the oysterfeet in Baltimore Harbor, circa1885. Photo: Collection oMarion Doss


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destroyed previous marsh habitat. Conse-quently, at a minimum, compensatory resto-ration o injuries caused by DWH oil andcollateral damage rom emergency responseactions should contemplate expecteddynamic change to ensure durability orestoration projects. At best, the long-termGul restoration plan would redress pastinsults and restore a resilient Gul ecosystemsimilar in unctioning to its historic base-line condition, within which compensatoryrestoration o habitat and natural resourcesinjured by the DWH oil release could besel -sustaining. President Obamas mandateto address historical and immediate ecologi-cal damage in the Gul provides an oppor-tunity or this ideal restoration strategy; theMabus Report, commissioned by PresidentObama and written by Secretary o theNavy Ray Mabus, provides a broad and boldvision or how to proceed with importantaspects o ul lling this mandate.

Fortunately, the compensatory damagesunds do not represent the only source o

support or DWH oil spill and broader Gulrestoration, so the limiting criteria laid outin OPA need not apply to all restorationactions that are taken in the wake o theDeepwater Horizon incident. For example,under the ederal Clean Water Act o 1972(CWA), the uses o monies rom water pol-lution penalties or illegal discharge o oil

into the ocean are not similarly constrained.CWA penalties are based on volumedischarged with an additional multiplier

or negligence. Particularly i negligenceis established as a signi cant actor to theblowout, CWA penalties may represent thebulk o the DWH restoration unds. The$500 million trans erred rom BP to theGul Coast Alliance does not appear to becontrolled by provisions tying the use othose unds to injured resources. Finally, it islikely that other major grantors will emerge

as the restoration process takes shape;these grantors may help to multiply thesynergistic bene ts rom related restorationprojects.

Our restoration guidance is there oreintended to target administrators o several

unding sources. Funding institutionswill value aspects o the Gul o Mexico

variously; or this reason, we have notprioritized the restoration actions that wedevelop. Nor have we made detailed esti-mates o the costs o these 15 restorationactions. Costs o compensatory restorationactions will vary with the scale o injuries

rom the oil spill that require compensa-tion. The multiple unding sources will havedi erent goals and constraints. Many o oursuggested actions address long-standingmodi cations o the Gul ecosystem that

t well into the strategies articulated in

initial expert responses to the spill (e.g., theMabus Report). Others are directly relatedto oil spill damage and compensatory res-toration. We o er these recommendationsto help guide allocation o resources whileplans are still being developed. Guidelines

or use o the unds provided by BP as aninitial payment to jump-start restoration arenow vague and will be developed by theadministrators. Details o how water pollu-tion nes will be allocated are likely to bedetermined by Congress. Consequently, our

strategy is to o er what we conclude arethe most infuential and justi able actionsto take, while emphasizing the principles orestoration that must guide all expendituresso as to maximize likelihood o success,achieve synergies o integration based uponecosystem connections, re-create lost eco-system processes associated with historicalecological baselines, and enhance resiliencethrough knowledge o ongoing and inevi-table environmental change.

1970s Passage o theClean Water Act providedthe ramework or regulatingenvironmental stressors onthe Gul ecosystem. Above,oil and natural gas spew

rom a broken cap in BayouSt. Denis in Louisiana. Photo:

Carrie Vonderhaar/OceanFutures Society/NationalGeographic Stock


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The interdisciplinary elds o restorationecology, conservation biology, and com-munity and ecosystem ecology all o er

scienti c guidance or restoration projects.Basic research in community and ecosystemecology sheds light on the mechanistic

unctions o habitats and the roles o directand indirect interactions between species inorganizing communities. Conservation biol-ogy o ers strategies or protecting habitats,species and their interactions in ecosystems.Restoration ecology tends to move aheadthrough practice, rather than via elabora-tion and subsequent testing o theory (Allenet al. 1997, Palmeret al. 1997, Peterson and

Lipcius 2003). These elds o er relatedapproaches to restoration, but no overarch-ing theory o restoration has emerged. Theabsence o a compelling theory that couldbe applied to species or habitat restora-tion implies that empirical assessment osuccesses and ailures o previous restorationactions should guide new decision-makingand that small-scale tests o restorationconcepts should be conducted be ore decid-ing on larger-scale projects (Bernhardtet al. 2005). Because so much was done under

the banner o restoration a ter the ExxonValdez oil spill, learning rom that historyseems prudent be ore restoration decisionsare made to compensate or DWH injuries tonatural resources o the Gul and to restoreits ecosystem services (see box, Page 11).

Lear i g rom the ExxoValdez restoratio e ortsIn response to the DWH oil spill, DennisTakahashi-Kelso, executive vice president

o Ocean Conservancy, wrote a letter inAugust 2010 to the government trustees othe DWH case, o ering practical guidance

based upon experiences rom the ExxonValdez restoration process. Addressed toDeputy Secretary o the Interior David Hayesand Under Secretary o Commerce JaneLubchenco, this letter drew upon a panelo scienti c experts that included two ous, Senner as panel lead and Peterson asparticipant, each with extensive experiencein habitat and species restoration a ter theAlaskan oil spill. In this letter, Dr. Takahashi-Kelso quotes President Obamas June 15,2010 charge to Navy Secretary Ray Mabus

and pledge to develop a long-term GulCoast restoration plan. Dr. Takahashi-Kelsoo ered support or a plan that acknowl-edges the importance o the NationalResources Damage Assessment (NRDA)restoration process, which is the processused or OPAs in-place, in-kind approach.But he stressed that restoration must alsogo beyond those constraints. We agreethat recognition o the dual mandate othe presidents wider plan and the narrowercompensatory restoration process driven

by OPA is critically important to achievingsustainable restoration. We build upon thisoverarching concept to design and advo-cate our speci c restoration suggestions.

Based in part on his own Exxon Valdezexperiences and those o Senner, Petersonand others, Dr. Takahashi-Kelso makesseveral undamental points about theprocess o restoration a ter natural resourcedamage that should be applied to the DWHoil spill restoration process. We modi y andexpand upon these points to ormulate our

Precedents and Principles orRestoring the Gul o MexicoEcosystem

Oyster ree s and mangroves(shown on Sanibel Island, FL)serve important unctions inthe Gul ecosystem. Photo:Brian Kingzett

Because so much wasdone under the banner

o restoration a ter theExxon Valdez oil spill,learning rom that historyseems prudent be orerestoration decisions aremade to compensate orDWH injuries to naturalresources o the Gul and to restore its ecosys-tem services.


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suggested ecosystem-based restorationguidance (Appendix I). A summary o themost relevant points rom the Takahashi-Kelso letter ollows: The restoration process should be trans-

parent to the public and should engagethe public in meaning ul dialogue overpotential actions rom an early point.

Quick settlement o damage claimswithout a legal mechanism to achievecompensatory unding or restorationo unexpected, delayed injuries is not inthe public interest. The legal settlementlanguage is critical because it dictatesthe scope o restoration possibilities.

Restoration should be broad to allowenhancement o injured resources overand beyond their status and conditionat the time o the oil spill so as to be

responsive to the need to account orpast degradation and, in the process,create a sel -sustaining system moresimilar to historic baselines.

The scope o possibilities to be consid-ered or restoration should be clearlyde ned and, or the compensatoryrestoration und, limited to resources,habitats and systems that were injuredby the hydrocarbon releases. Otherwise,public expectations can be misguidedand overly expansive, which unnecessar-ily causes disappointment and bitterness.

Care must be taken to avoid harmingthe ecosystem and its services by imple-menting untested projects that couldresult in negative rather than positivenet impacts on resources.

The restoration program or programs,separating the Gul ecosystem restora-tion rom compensatory restoration

or spill injuries, should be ecosystem-based, integrating component projectsinto a comprehensive restoration planacross the northern Gul .

Division o restoration unds into stateblock grants would not achieve thesynergies possible, resiliency neededand scope required to address the mostcritical challenges in sustaining Gulecosystems and their services, becausethose bigger challenges tend to beregional in scope and require coordi-nated responses.

Restoration must also be based upon sci-ence and developed using peer review byindependent scientists without conficts ointerest. Some o the science needed toconduct success ul restoration o importantnatural resources in the Gul ecosystem,including the injuries caused by the Deep-water Horizon disaster, is not complete andneeds urther development be ore restora-tion can be con dently achieved (Bjorndalet al. 2011).

The Mabus ReportIn addition to the Takahashi-Kelso letter,we take guidance rom the Mabus Report(2010), which was prepared by the secre-tary o the Navy in response to the Presi-dents charge. Fundamentally, we endorsethe recommendation o the Mabus Reportthat an in ormed and independent undingstructure is necessary to lead to long-termecosystem, economic, and health recoveryin the Gul (Mabus, Page 5).

Speci cally, the Mabus report recom-mended the establishment o a Gul CoastRecovery Council that should work withexisting ederal and state advisory com-mittees, as appropriate, to ensure thatrelevant scienti c and technical knowledgeunderpins recovery planning and decisionmaking, and that research, monitoring,

and assessment e orts are organized. TheCouncil should also provide oversight andaccountability into Gul o Mexico recoverye orts by developing quanti able per or-mance measures that can be used to trackprogress towards recovery goals (Mabus,Page 8). However, we recommend that the(perhaps inadvertently) restricted ocus onstate and ederal agencies be broadened toinclude academics and nongovernmentalagencies. We enthusiastically concur withthe ve guiding principles or restoration

(see box, Page 12) presented in the Mabusreport, though we o er several cautions.We note that sediment management issuesare complex, and some suggested interven-tions may be so narrowly ocused as to becounterproductive. Additionally, monitoringconditions and processes is necessary, andthe metrics o success must be identi edand used to adapt the restoration actions asneeded to achieve their goals.

1989 A worker operatesrespirator hoses during an oildispersant application test onSmith Island in Prince WilliamSound a ter the Exxon Valdezoil spill. Photo: Alaska ResourcesLibrary and In ormation Service


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Cormorants sit on stakesplaced by researchers next tonewly planted sea grass in theFlorida Keys. The birds drop-pings serve as ertilizer or theplants. Photo: Florida Fish andWildli e Commission

Ecosystem Services

Natural ecosystems and their constituentorganisms engage in a wide variety oprocesses. Some o these processes serveneeds o other organisms, communitieso organisms, and ecosystems; these clus-ters o bene cial processes are known asecosystem services. Valuable ecosystemservices have historically been taken

or granted and there ore not properlyconsidered in the process o permittingdevelopment projects. One example isthe pollination o crops by honeybees.I armers had to pay or the services opollination instead, the costs o produc-ing crops would be much higher. Therecent decline o honeybee populationshighlights our need to protect valuableecosystem services as we modi y naturalsystems.

Coastal wetlands have or decadesbeen recognized or the high value o

their many ecosystem services, and theimportance o this delivery o goods andservices has been refected in ederaland state legislation or the protection ocoastal wetlands. The mantra o no netloss o wetlands has guided approachesto estuarine management or decades.Tidal marshes are valued, protected andrestored in recognition o their ecosystemservices (MEA 2005), which include:

high primary productivity o emer-gent vascular plants as well as single-celled benthic microalgae and habitatprovision supporting the ood websleading to sh and wildli e;

serving as a bu er against stormwave damage to the adjoining veg-etation and human development onhigher ground;

shoreline stabilization and erosionprotection;

food water storage; water quality maintenance, including

ltering out sediments, nutrients andpathogens;

biodiversity preservation, especiallyo a suite o endemic, o ten threat-ened or endangered vertebrates;

carbon storage as peat is accumu-lated, buried and stored, thus bu er-ing greenhouse gas emissions; and

socioeconomic bene ts, such as sus-taining the aesthetics o coastlines,maintaining a heritage and historicalculture, supporting ecotourism, serv-ing as a living laboratory or natureeducation, and promoting psycho-logical health and supporting shingand water owl hunting.


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Mabus Principles (2010)

Our committees reactions are in italics; details appear later. The ollowing serve as ideal and guidingprinciples to restoration toward states to which the Gul can realistically aspire. The Mabus Report assertsthat they serve as the drivers or achieving the vision o resilient and healthy Gul o Mexico ecosystems(Mabus, Pages 38-39).

Principle 1: Coastal Wetland and Barrier Shoreline Habitatsare Healthy and Resilient. In order to sustain the many ecosystemservices upon which humans rely, coastal habitats must be healthyand resilient. Reversing ongoing habitat degradation and preservingthe remaining healthy habitats is a key principle. It must be recog-nized that even the healthiest ecosystems are dynamic, so a restora-tion e ort should not ocus entirely on a xed ootprint. A keyobjective o this principle is to bring greater balance to managingthe Mississippi River and other rivers or food control, navigation,

and ecosystem restoration. Another objective is to retain sedimentsin coastal wetlands, be ore they leave the river channel to the Gul(Mabus, Page 38).

We concur with this guidance,although we express serious con-cern about whether the Mississippi River, with all its channelizationand engineering constraints suchas levees and dams, brings enough

sediment to sustain wetland elevations beyond the immedi-ate ootprint o the river-mouth

delta. We suggest that the organic soils o the inter-levee area can beharmed by the high concentrationo nutrients in the river. We also

suggest that lling dredged chan-nels and preventing new wetland losses will be much more e ectiveand less expensive than alternativerestoration approaches.

A Fou datio orDurable RestoratioWith guidance rom Dr. Takahashi-Kelsosletter to government leaders, rom pub-lished papers on ecosystem-based restora-tion, and rom our own experience, we

eel that restoration in the Gul must reston a solid oundation that acknowledges

the past, is realistic about the uture, andrecognizes the interdependence o habitat,species, and human beings in the ecosys-tem. There ore, durable and success ulrestoration in the Gul o Mexico must:

1. Recognize that ecosystem resilience hasbeen compromised by multiple humaninterventions predating the DWH spill;

2. Acknowledge that signi cant utureenvironmental change is inevitable andmust be actored into restoration plansand actions or them to be durable;

3. Treat the Gul as a complex and inter-connected network o ecosystems romshoreline to deep sea; and

4. Recognize that human and ecosystemproductivity in the Gul are co-depen-dent, and that human needs rom ande ects on the Gul must be integral torestoration planning.


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Principle 2: Fisheries are Healthy, Diverse and Sustainable.The Gul is home to the largest commercial shery in the contigu-ous United States. The total trip expenditures or recreational shingin the Gul states in 2008 were nearly $1.5 billion. Key objectives othis principle may include incorporating testing and other mecha-nisms or sea ood sa ety to ensure that sh and shell sh are sa e orhuman consumption, and working through regulatory and other

conservation mechanisms to restore populations o sh and shell sh(Mabus, Page 38).

We concur that conservation regu-lation will be required to render

shing sustainable in the Gul ,but we also identi y habitat protec-tion as a major additional processneeded to develop the ecosystem

support or resilient sh and shell-

sh populations.

Principle 3: Coastal Communities are Adaptive and Resilient.The needs and interests o Gul communities vary and the moste ective solutions will be based on local conditions. Given that mucho the land a ected by the oil spill is privately held, ull restorationwill rely on local citizen support. The impacts o climate change,including sea level rise and more requent and intense storms,will likely alter the landscape signi cantly, orcing communities toreassess their priorities. Key objectives o this principle may includeproviding coastal managers with in ormation and tools to make

better land use and public health decisions, and increasing aware-ness o the connection between ecosystem and community resilience(Mabus, Page 38).

We concur and go urther to add that a long-term process o social engagement with local communi-ties to encourage understandingo the scope o unavoidable

uture change is required to support development o community resilience.

Principle 4: A More Sustainable Storm Bu er Exists. Persistentcoastal land loss, compounded by sea level rise, is deterioratingnatural lines o de ense, leaving coastal communities vulnerable totropical storms. Natural and engineered systems are necessary toreduce exposure and ensure protection. Key objectives o this prin-ciple may include maintaining and expanding natural storm bu erssuch as wetland and barrier islands and improving decision-makingwith regard to structural protection and navigation interests so thatthese complement and enhance restoration o natural systems.Another objective is the reduction o risk posed to people and pri-vate property through e ective planning, mitigation, and balancingo interests (Mabus, Pages 38-39).

We concur while recognizingthat hardened erosion protection

structures and beach nourishment degrade barrier island ecosystem

services and require compensatory restoration o impacts to natural resources.

Principle 5: Inland Habitats, Watersheds and O shore Watersare Healthy and Well Managed. Communities across the nationrely on our ability to maintain healthy, resilient, and sustainableocean, coasts, and Great Lakes resources or the bene t o presentand uture generations. Additional stressors on the health o thesesystems and the resources they support include over shing, pollu-

tion, and coastal development. Further, ocean and coastal resourcesare directly and indirectly impacted by land management and usedecisions in the watersheds that drain into the Gul o Mexico. Keyelements o this principle include improving management o agricul-tural and orest lands; restoring foodplains and wetlands to improvewater quality by uptake o nutrients, reduce food risks, and enhancewildli e habitat; reducing erosion and nutrient runo rom agricul-tural and developed land; and using state-o -the-art planning toolsto deliver comprehensive, integrated ecosystem-based managemento resources (Mabus, Page 39).

We concur with every point.


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The Deepwater Horizon well blowoutoccurred April 20, 2010, resulting in explo-

sions and res on the drilling rig that killed11 men, injured many more and led twodays later (ironically on Earth Day, April 22)to sinking o the rig to the seafoor about1,500 m below the sur ace. On April 22,substantial amounts o orange-brown crudeoil appeared at the sur ace, con rmingthat a well blowout had occurred at thedrill site. As the oil continued to fow or85 days, totaling an estimated 4.9 millionbarrels, the nonpro t organization SkyTruthassembled and posted satellite images rom

in rared and radar sources depicting thelocation o the sur ace oil slick. By June 25and 26, the slick had covered more than24,000 square miles o the sea sur ace inthe northern Gul o Mexico (Norse andAmos 2010). By July 16, the day a ter all oilfow rom the stricken well had ended, anarea o about 68,000 square miles o theGul sur ace had been covered by oil (Norseand Amos 2010).

In late April, winds in the Gul typicallyswitch to the seasonally characteristic,southwesterly onshore direction, whichwould have brought the oil quickly andheavily onto shore and into shoreline habi-tats. Fortuitously, the spring o 2010 wasnot typical and lacked the spring period oonshore winds. In addition, much o thesur ace oil was caught up in an eddy thathelped keep it at sea and prevent its trans-port via the Loop Current southward to theFlorida Keys and then into the Gul Streamand Atlantic Ocean. As a consequence, oilwas not detected reaching shore until

June 3 in Alabama. Oil ultimately groundedon hundreds o miles o beaches, marshes,

sea grass beds, tidal fats and oyster ree s,despite intensive response e orts to preventand minimize this outcome. These e ortsincluded massive applications o dispersantsboth on the sea sur ace and injected intothe plume emerging rom the seafoor,skimming foating oil rom the sea sur ace,burning it at sea, installing booms alongmarshes and other sensitive shorelines,diverting reshwater river discharges intomarshes in an attempt to prevent intrusiono oil slicks, and dredging and lling to

construct arti cial berms on the coastline.Although no damage assessment test dataare available, eld observations suggest thatthese response actions caused some levelo collateral injuries to wildli e and habitats,which there ore represent indirect damageattributable to the Deepwater Horizonblowout (Table 1).

Despite the emergency response e orts, theoil ouled many acres o the most valuablemarsh edge habitat, ouled ocean beaches,

orced closures o shell sheries and n-sheries and decimated the economically

vital Gul tourism industry, extending atleast as ar as southwest Florida (Table 1).Many birds o several species were killedalong shore, including brown pelicans andother species that were nesting during thatspring-summer season, and marsh residentslike rails. Lesser amounts o oil entered low-energy muddy habitats o marshes and mudfats, where it can persist without com-plete weathering or years. Consequently,the Deepwater Horizon oil release also

The skyscrapers o New Orleansare visible behind housesfooded by Hurricane Katrina.Photo: Tyrone Turner/NationalGeographic Stock

The DWH Oil Spill i the Gul o Mexico

Acute and Chronic Stressors on theGul o Mexico Be ore and A ter theDWH Oil Spill

The state o the Gul andits coastal zone imme-diately be ore the DWHincident was ar rompristine, with countlessstressors having alreadyaltered and degraded theecosystem.


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resembled earlier shallow-water oil spillsby a ecting shoreline habitats o value towildli e and to human enterprise.

Di ere ces betwee DWHa d other oil spillsAs anticipated, the Deepwater Horizonblowout led to the oiling o sea-sur aceand shoreline habitats and to consequentdamage to natural resources. In contrastto previous spills, however, the majorityo the oil and gas released at the well-head remained ar below the sea sur ace.An estimated 500,000 tons o gaseoushydrocarbons perhaps hal o all hydro-carbons released by the blowout (Joyeet al. 2011) entered the ocean yet weremetabolized by heterotrophic bacteria inthe deep ocean, and only 0.01 percent wasvented into the atmosphere (Kessleret al. 2011). A large raction o the oil was alsoretained beneath the sea sur ace becauseo the unique physical chemistry created bythe deepwater blowout conditions. Underconditions o high-pressure deepwater dis-charge o hot oil and gas, the entrainmento cold seawater, caused by violent andturbulent fows at the wellhead, created avariety o dispersed phases, including ne-scale oil droplets, gas bubbles, dissolvedgas, oil-water emulsions and gas hydrates.The collective buoyancy o this mixture ooil and gas created a rising plume, romwhich much o the oil and gas separatedand was trapped by ocean strati cation atdepths o 800 to 1,200 m and subsequentlydefected and transported by ambient cur-rents (Joyeet al. 2011). Massive productiono methanotrophic bacteria was associatedwith the oil and gas in this depth stratum,causing a detectable depression o oxygenlevels, but it did not approach anoxia (Joyeet al. 2011).

The natural dispersal o oil induced by pro-cesses at the wellhead may have renderedthe application o 1.8 million gallons otoxic Corexit dispersant unnecessary, butthe net e ect was the novel dispersal o theoil in very ne droplets and retention o alarge percentage o the oil droplets in themesopelagic and bathypelagic depths othe deep sea. Such dispersal and reten-tion o oil in the water column as nelydispersed droplets exposes organismsliving there or passing through to bioavail-able, toxic oil, a ecting copepods, salps,

invertebrate larvae and other particle-consuming, mesopelagic zooplankters.Subsequent agglomeration o oil particles,sediments and marine snow, possibly medi-ated by release o muds rom the well andby sticky bacterial exudates (Hazenet al. 2010), acilitated the transport o this oil tothe seafoor, where observations o dead,so t corals and crinoids on hard bottomand polychaetes and brittle stars on so tbottom were associated with dark depositso hydrocarbon-enriched sediments (Fisher2010). Consequently, the process o dis-persing the oil led to widespread exposureso particle- eeding organisms o the deeppelagic and seafoor realms. This oil stimu-lated massive production o microbes, withunknown consequences to deep-ocean

ood webs, in part because o the likelymortality and eeding incapacitation o theparticle eeders that might consume thesemicrobes (Table 1).

Clearly, the Deepwater Horizon oil releasedi ers so dramatically rom all previous,well-studied crude oil spills that it requiresdevelopment o a completely new concep-tual model, applicable not only to this spillbut also to all uture deepwater releases(Petersonet al. in press). Elaboration othis emerging model or deepwater wellblowouts, including rigorous ecotoxicologi-cal models, is urgently needed to document

and understand the deep-ocean impacts othis oil spill, and especially to allow or thee ective compensatory restoration o lostecosystem services.

What DWH i dicates aboutailures i the deep-sea oil

drilli g programThe National Commission on the BP Deep-water Horizon Oil Spill and O shore Drilling(Grahamet al. 2011a) provides an insight uland comprehensive account o the many

actors over multiple time scales that led tothe well blowout on the Macondo Prospectand the resulting loss o li e, environmen-tal contamination, and impacts to humanenterprise along the northern Gul Coast.The commission concluded that the spillwas preventable. According to the commis-sion, the immediate causes o the calamitywere ailures in management by BP,Halliburton, and Transocean on the Deep-water Horizon rig at the end o the drillingprocess. Communications ailures among

The DWH oil releasedi ers so dramatically

rom all previous, well-studied crude oil spillsthat it requires develop-ment o a completelynew conceptual model.


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Damage rom sur ace oil at sea

Resource Damage

Seabirds Tens to hundreds o northern gannets, brown pelicans,laughing gulls, terns, black skimmers and many others

were killed and experienced tness losses that reducedreproductive capacity.

Sea turtles Hundreds o loggerhead, Kemps ridley, green andleatherback turtles (all threatened or endangered spe-cies) experienced tness loss or were killed.

Marine mammals Bottlenose dolphins were killed.

Sargassum community Plants were soaked with oil, hatchling sea turtles oiled, juvenile game sh exposed, orage sh and inverte-brate prey exposed, resulting in community mortalitiesand tness losses.

Fish and crabs Blue crab in early li e stages took up oil and dispersantwith likely e ects on tness; sh in early li e stageswere similarly exposed.

Cannonball jelly shand smaller gelatinouszooplankton

Physical ouling likely resulting in loss o li e andtness.

Damage rom oiling o shoreline habitats

Resource DamageCoastal marsh habitat Loss o ecosystem services rom hundreds o acres o

heavily, moderately and lightly oiled marsh

Ocean beach habitat Some mortality rom ouling o eeding apparatus omole crabs, bean clams, amphipods and polychaetes(prey or sur sh and shorebirds, reducing their pro-ductivity)

Sea grass bed habitat Some mortality o sea grass with loss o its ecosystemservices and mortality o sensitive species such as crus-taceans and echinoderms

Tidal fat habitat Many areas o partial loss o ecosystem services oproducing sh, crabs and shrimp

Oyster ree habitat Polycyclic aromatic hydocarbon contamination o oys-ters and likely slower growth and production; probabledeaths o some resident crustaceans such as amphi-pods, shrimp and crabs.

Nearshore species More bird deaths, including rails, pelicans, terns, blackskimmers, shorebirds, gulls, wading birds; reptiledeaths including terrapins and alligators; deaths omarsh mammals such as river otters

Table 1

Major Natural Resource Damage From DWH Well Blowout

An oiled pelican stands on a

rock jetty at Grand Isle, LA,a ter the Deepwater Horizonspill. Photo: Eileen Romero/ Marine Photobank

Oil rom the spill is visible on amarsh. Photo: NOAA


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Dying corals have been oundnear the Deepwater Horizonsite. Photo: NOAA OER andBureau o Ocean EnergyManagement, Regulation andEn orcement

Two shing vessels drag an oilboom a ter trapped oil is setablaze in the Gul . Controlledburns were conducted toprevent the spread o spilledoil. Photo: Je ery TilghmanWilliams, U.S. Navy/MarinePhotobank

Damage rom subsur ace dispersed oil and gas

Resource Damage

Pelagic suspension eeders Ingestion o particulate oil and ouling o eedingapparatus caused widespread mortality o deep-sea,mesopelagic and benthopelagic guilds o particle eed-ers (e.g., salps, appendicularians, jellies, zooplankton),altering energy trans er through the ood web

Benthic suspension eed-ers on hard bottoms andsuspension and deposit

eeders on so t bottoms

Ingestion o particulate oil and ouling o eedingapparatus caused widespread mortality o so t corals,crinoids, bryozoans, brittle stars, polychaetes thebenthos o both hard and so t bottoms

Heterotrophic microbialproduction throughout thewater column, especially in8001,200m o water

Massive organic carbon enrichment resulted inlocalized oxygen reductions and disruptions in the

ood web.

Collateral damage caused by response actions

Activity Damage

Soot releases intothe atmosphere anddeposition on the seafoor

rom burning oil

Wildli e health e ects o respiring soot and possiblebenthic e ects o its ocean deposition

Use o mechanical skim-mers to remove sur ace oil

Contact with skimmers resulted in wildli e injuries andatalities

Dredging and lling tocreate berms o shore in

attempts to block oil romgrounding on naturalhabitats

Mortality o benthic invertebrates, which serve as keyprey or shrimp, crabs and demersal sh, and mortality

o seabird and sea turtle eggs

Intensive repeated beachexcavations and raking toremove tarballs

Simultaneous mortality o benthic invertebrates suchas mole crabs and bean clamsimportant prey or sur

shers and shorebirdsplus removal o wrack, whichserves as habitat or small crustaceans and insectsconsumed by plovers and other shorebirds

Sea turtle nest relocationsrom Gul Coast to eastern

Florida beaches

Risks o imprinting survivors to return to live along andnest on a di erent coast

Boom deployment o -shore o marsh shorelines

Direct physical damage to marsh plants as boomsbreak loose and are driven by waves into the marsh;occasional trapping o oil and waterbirds together,resulting in oiling and enhanced mortality o the birds

Use o 1.8 million gallonso Corexit

There is uncertainty about Corexit-generated chronicexposures to pelagic organisms, and likely tnesslosses and direct mortality o particle eeders.


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separate specialists and ailure to recognizethe seriousness o inherent risks were parto a complex sequence o multiple ail-ures that acilitated an improbable event.Although the blowout may have beenimprobable, an underlying and long-stand-ing culture o indi erence within both thepetroleum industry and the ederal regula-tory agency (the ormer Minerals Manage-ment Service) set the stage or the blowoutand made such an event inevitable (Grahamet al. 2011a).

As the most accessible oil reservoirs arebeing depleted while the demand oroil increases, the petroleum industry hasextended exploration and production intoprogressively deeper waters. This pro-cess has required remarkable engineeringinnovation or success ul drilling in oceanwaters over a mile deep and extraction o

oil several miles deeper below the seafoor.Oil at such depths exists under ar greaterpressures than oil extracted rom shal-low depths, thereby increasing the needto control pressure in the well. Despiteremarkable advances in engineering or oilexploration and production in deep water,corresponding progress has not occurred inblowout prevention, emergency response,clean-up and mitigation technologies. Someo the same crude tools used to respond tothe oil release at the sur ace o the ocean

by the grounded Exxon Valdez tanker in1989skimming and sur ace boomingwere applied again 21 years later. Neitherthe industry nor government regulators haddeveloped e ective new technology orshutting down a deepwater, high-pressureblowout, as evidenced by the well-pub-licized and remarkably rapid conceptualdevelopment, construction and testing otools and approaches by the industry in theweeks a ter April 20, 2010.

Industry complacency, ailure to recognizerisk and the di erences between deep andshallow oil releases, and the confictedmission o the ederal regulatory agencycharged with promoting development andproduction o oil and gas while simulta-neously acting as regulator meant thatappropriate advances were not made inenvironmental sa eguards to match theheightened risks and challenges o deepwa-ter drilling. The development and testing oe ective and reliable technologies to cap arunaway blowout o a deep or ultra-deep

well should have preceded the emergencyneed or them. Application o dispersantat the wellhead should at least have beentested in mesocosms under conditionsmimicking a deepwater blowout be ore thedecision to use it or the DWH. Toxicity testsusing the unique deep-sea particle eedersat risk to nely dispersed oil should havebeen conducted in advance o the decisionto use dispersants. In addition, scienti cadvances needed to understand the biologi-cal communities o the deep pelagic andbenthic oceans and the physical transportregime that carries oil a ter release into theenvironment in deep water had also stalled.As a consequence, assessment o oil spillimpacts rom deepwater blowouts was seri-ously compromised.

As tragic as the DWH blowout was, it o ersan opportunity. As with the 1969 blowout

in the Santa Barbara Channel,1 which ledto passage o the National EnvironmentalPolicy Act (NEPA), and the moratorium onoil drilling o the Cali ornia coast and otherstates, the DWH blowout could stimulateinterest in protecting the economically,socially and environmentally critical Gulregion o the United States.

Ecosystem a d aturalresource impacts o oil a d

gas releaseBe ore the Deepwater Horizon blowout,the prevailing paradigm o maritime oilbehavior, biological exposure pathways

ate, and consequent impacts to naturalresources was based upon syntheses o pastshallow-water, largely nearshore oil spills(e.g., NRC 2003). In such spills, crude oilremains at the sur ace, unless mixed intothe water column by strong sur ace waves.I discharged below the sea sur ace, the oilrises rapidly to the sur ace because o itsbuoyancy. Gaseous hydrocarbons such asmethane also rise to the sea sur ace, primar-ily as bubble plumes, and disperse rapidlyinto the atmosphere. The crude oil on thesea sur ace is viscous and sticky; it oulsthe eathers o seabirds and the coats o

ur-bearing marine mammals, causing highrates o mortality by disrupting thermoregu-lation and through ingestion o toxins asthese birds and mammals preen eathers or

ur (Riceet al. 1996). Other organisms thatuse the ocean sur ace, such as sea turtles,

Despite remarkableadvances in engineer-ing or oil explorationand production in deepwater, correspondingprogress has not occurredin blowout prevention,emergency response,clean-up and mitigationtechnologies.

Ships clean up oil in the Gul oMexico using the same crudetools that were used a ter theExxon Valdez spill 21 yearsearlier. Photo: James Davidson


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are exposed to physical ouling, potentiallyresulting in death. Smooth-skinned marinemammals, such as killer whales and harborseals, risk mortality and sublethal e ects ongrowth, reproduction and behavior rominhalation o oil globules while breathingthrough their blowholes and rom inhalingthe more volatile toxic hydrocarbons in theatmosphere. The foating oil is transportedby winds and sur ace currents and can endup grounded on shores, where it exposes,

ouls and kills intertidal and shallow subtidalorganisms, including salt marsh plants, seagrasses, macroalgae and oysters that pro-vide important biogenic habitat (Teal andHowarth 1984). Oil that penetrates into thesediments su ciently, so that sunlight doesnot reach it and oxygen cannot be readilyresupplied rom the atmosphere, can persist

or many decades without degradation(Bou adelet al. 2010), exposing animals

that excavate those sediments to orm bur-rows (Culbertsonet al. 2007) or to uncoverin aunal prey. This exposure can causesublethal losses o tness that can havepopulation-level consequences or severalyears (Petersonet al. 2003b).

The DWH well blowout indeed led tosubstantial coverage o the sea sur ace and

consequent ouling and killing o seabirds,sea turtles, bottlenose dolphins and perhapsother marine mammals, as expected romtraditional shallow-water spills (Table 1). Theseabirds that experienced the most loss oli e include northern gannet, brown pelican,gulls, terns and the black skimmer. Abortedbottlenose dolphin etuses were observed.Sur ace oil also collected in the foatingSargassum , a large brown alga that ormsa unique foating nursery habitat in theGul and other seas.Sargassum supports

large numbers o small shes, including

A menhaden shing boat inEmpire, LA. Photo: LouisianaSea Grant College Program/ Louisiana State University

Oil that penetrates intothe sediments su ciently,so that sunlight doesnot reach it and oxygencannot be readily resup-plied rom the atmo-sphere, can persist or

many decades withoutdegradation.

The Menhaden Fishery in the Gul o Mexico

The Gul menhaden shery dates tothe late 1800s and remains economi-cally important today. With landings o468,736 tons in 2004, the Gul men-haden landings comprise 11 percento all U.S. shery landings, and Gulmenhaden support the second-largestcommercial shery in the United States(Pritchard 2005). The menhaden catchrecords or years be ore World War IIare incomplete, but annual landings

rom 1918 to 1944 probably rangedrom 2,000 to 12,000 tons (Nicholson

1978). Landings appeared to increaserom the late 1940s through 1970, with

a peak o 521,500 tons landed in 1969(Chapoton 1970, 1971). Landings con-tinued to increase through the 1970sand 1980s, exceeding 800,000 tons orsix consecutive years (1982 to 1987)and peaking at 982,800 tons in 1984(Smith 1991). Since 1988, the land-ings have ranged rom 421,400 tons in1992 to 761,600 tons in 1994, show-ing no apparent trend. Although themenhaden landings do not appear to bedeclining urther rom the 19821987levels, the potential or over shing isstill a concern and must be consid-ered in the uture management o this

important shery. Because menhaden isa orage sh or many predatory pelagic

shes, seabirds and marine mammals,reductions in stock levels by shingmay have consequences or the healthand viability o populations o highertrophic-level predators (Bots ordet al. 1997). To the extent that these higher-order predators are protected by law,these indirect ecosystem-based issuesassociated with menhaden harvest arelikely to represent a critical manage-ment concern. The menhaden sheryshistory indicates limited consideration

or ecosystem-based impacts, yet asthe ocean environment continues tochange, management o this highly pro-ductive sh stock will need to take intoaccount a broader range o actors thatdrive menhaden dynamics, includingDWH oil spill impacts, and a wider rangeo consequences o shing, includingimpacts on threatened and endangeredspecies and on species injured by theoil spill. Menhaden represent one omany sh stocks or which ecosystemconsequences o shing need to beconsidered in a context o the changingGul environment so that sustainability isincorporated into management.


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juvenile blue n tuna, cobia and wahoo, aswell as crustaceans and other invertebratesthat help eed juvenile predatory pelagic

shes. In addition, this is the critical habitator juvenile loggerhead, Kemps ridley and

other sea turtles rom the time o leavingthe nest until they return to coastal waters.Large numbers o sea turtle hatchlingswere recovered dead and dying rom theSargassum .

The state o the Gul and its coastal zoneimmediately be ore the DWH incident was

ar rom pristine, with countless anthropo-genic stressors having already altered anddegraded the ecosystem. In the Gul andother ocean ecosystems, anthropogenicdegradation is a historically cumulativeprocess (Jackson 1997, 2010, Jacksonet al. 2001, 2011), and an understanding o thatdegradation process is critical to success-

ul restoration. Stressors can synergisticallyintensi y their impacts over time and acrosssystems and species in ways that may resultin alternative and less desirable ecosystemstates (Sche eret al. 2001). Thus, attemptsto repair the consequences o more recentdisturbances in any ecosystem will neces-sarily ail unless restoration addresses all othe drivers o degradation both present andpast. Consequently, the restoration shouldincorporate an understanding o the base-line natural processes o the ecosystem, thehistorical degradation o those processes,and the way in which progressive environ-mental changes in the ecosystem mighta ect restorative actions. The durability orestoration depends upon consideration othese actors. This section outlines someo the major historical and anthropogenicstressors on the Gul ecosystem.

Humans have been active in the Gulecosystem or thousands o years, ranging

rom centuries o subsistence shing andharvesting o nearshore resources by NativeAmericans to oil and gas extraction in the20th and 21st centuries. The impacts ohuman activities include bottom habitatmodi cation and population reductionsin targeted sh and shell sh stocks and inspecies killed as bycatch rom large-scalecommercial and recreational shing; chan-nelization and damming o major riversfowing into the Gul ; widespread and rap-idly accelerating coastal development with

its attendant modi cation o hydrology,

increases in impermeable sur ace area, anddredge-and- ll activities in wetlands; extrac-tions o subsur ace fuids such as oil, gasand groundwater, which induce subsidence;water quality degradation rom agricultural,urban, and industrial runo o nutrients;and the burgeoning impacts o anthropo-genically induced global climate change.The Gul has endured the consequences ouncontrolled nutrient runo and eutro-phication because o agriculture upstream(Rabalaiset al. 2002, 2007); over shing andassociated habitat destruction rom trawl-ing; and loss o habitat because o coastaldevelopment, land subsidence, channeliza-tion o wetlands, intensi cation o severestorms, and sea level rise. The historicalcontext o each o these human modi ca-tions o the ecosystem is presented below.

Ce turies o shi g i theGul o MexicoThe rst signi cant human impact onthe Gul ecosystem was probably causedby shing in coastal estuaries by NativeAmericans. Although no recorded evidenceexists, Native American shing may haveparticularly a ected accessible species suchas oysters near shore (Jacksonet al. 2001,Lotzeet al. 2006). This e ect may havebeen minimal: From the time o Columbuss

landing through the early 1600s, there wereaccounts o large abundances o sh, oys-ters, sea turtles and marine mammals oundin the Gul and the Caribbean. However,by the early 1800s, many o these organ-isms were already being over shed (Jackson1997, Jackson et al. 2001), and exploitationincreased through the 19th century. The seaturtle shery peaked in 1890, when turtlesranked 10th among shery products romGul states and th in Texas, and declinedsharply a ter 1892 due to overexploitation

(Doughty 1984).

1890s Green turtles are pre-pared or shipping to New York

rom Key West, FL, in 1898.The Gul sea turtle sherypeaked in the late 1800s andthen declined sharply becauseo overexploitation. Photo:Florida Keys Public Libraries

Damage to the Gul o Mexico Prior to theDWH Oil Spill


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Advances in shing technology a ectedthe Gul as vessels and catching devicesimproved the e ciency o shing. Thetransitions rom sailing vessels in the late1800s to steamers in the early 1900s andthen to diesel-powered vessels in the 1930seach increased the impact that shing hadon marine populations. The introduction opurse seines and longlines in the late 1800s,otter trawls or ground sh and shrimp in theearly 1900s, and more recent advances suchas durable nylon bers or nets, Loran-C,and GPS navigation systems dramaticallyincreased e ciency, the ability to targetspeci c sites, and the size o catches. Re rig-eration also helped increase demand bycreating globalization o markets.

These technological advances in the com-mercial and recreational shing industryhave contributed to over shing and the

subsequent decline o major sheries in theGul , including Spanish and king mackerel,red snapper, several species o grouper, reddrum and many pelagic shark species (UNFAO 2005, Colemanet al. 2004a, Baumand Myers 2004). The U.S. National MarineFisheries Service reported that in 2002, the

ve Gul Coast states landed a total o morethan 1.7 billion pounds (771,800,000 kg)o sh, including Gul menhaden (see box,Page 20) and shell sh, worth more than$705 million. These landings, however, do

not include the many pounds o bycatch(including juvenile commercial shes, orageshes, birds, sea turtles and marine mam-

mals) that are associated with many sheries(Mooreet al. 2009), making the totalextraction o sh and wildli e rom sheriesmuch greater.

Gul landings o shrimps and oystersaccount or about 68 and 70 percent,respectively, o total U.S. landings. Althoughimpacts o shing on populations o theseanimals are not well documented in theGul , the indirect e ects o their harveston the benthic habitats and the commu-nities o invertebrates and sh that theysupport have been well studied in recentdecades. Trawling or shrimp and ground shdisturbs bottom habitat and reduces thespecies diversity, abundance and biomasso bottom-dwelling organisms that serve asa ood source or many demersal sh andcrustaceans (Collieet al. 1997). Di erentassemblages o sh and crustaceans canalso be associated with habitats requently

disturbed by trawling, indicating shi ts incommunity structure at multiple trophiclevels (Wellset al. 2008). Such bottomdisturbance resets the benthic invertebratecommunity to an early successional stageo small, short-lived invertebrates. Whencombined with the loss and degradation ocoastal habitats induced by other stressors,continued intense shing pressure andbottom disturbance associated with trawlingand dredging may cause even more habitatmodi cations and reductions in sh stocks.

Fishing is a major pillar o the contemporaryGul coastal economy. Achieving sustainableharvest levels at higher stock abundanceswould result in millions o dollars worth oenhancement to Gul state economies. OurGul restoration actions under Theme 3 (seePage 75) include suggestions or achievingsustainable levels o extraction o sh and

shell sh at high yields while also minimizingimpacts on wildli e.

Pollutio i the Gul

Trends in nutrient loading and pollutionNutrient loading, sedimentation and dis-charges o other pollutants into the Gulhas increased over the past 200 years asa consequence o more intense humanoccupation, development and use o landin the Mississippi River watershed and otherrivers entering the Gul (Turner 2009). Theconcentration o nitrate and phosphorus inriver systems that eed into the Gul , such asthe Mississippi, increased three- to ve oldbetween the early 1900s and the 1990sand may continue to rise with increas-ing demands or ood and, more recently,

or corn and other crops used in ethanolproduction in the Midwest (Figure 2; Turneret al. 2007). The concentrations o pollut-ants such as heavy metals have increasedin the sediments, and these increases areprobably associated with oil drilling activitiesin the Gul (Vazquezet al. 2002). Increasedlevels o mercury and some other toxic con-taminants in the Mississippi River and otherrivers leading into the Gul can be linkedto settlement o the Midwest by Europeanimmigrants in the mid-1800s. Contaminantconcentrations o heavy metals peakedin the 1960s and have since declined,primarily in response to environmental lawsenacted in the 1970s such as the CleanWater Act (Wiener and Sandheinrich 2010).

Late 1800s Sailing vesselswere replaced by steam vessels.Credit: NOAA

The concentration o nitrate and phosphorusin river systems, such asthe Mississippi, that eedinto the Gul increasedthree- to ve oldbetween the early1900s and the 1990s.


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Despite regulatory protections, mercuryand organic pollutants, such as DDT andPCBs, which were released into the Gulwatersheds be ore e ective regulation, havegradually biomagni ed to concentrationsadversely a ecting apex predators (Wienerand Sandheinrich 2010).

Impacts o nutrient loadingand pollutionSalt marshes, sea grass meadows andoyster ree s act as lters or nutrientsand other pollutants, but the process otrapping excess nutrients, heavy metalsand toxic organic chemicals has ecologicalconsequences (Dameet al. 1984). Althoughnutrient enrichment is not the primarycause o wetland loss in the Gul , it appearsto contribute to it. From 1998 to 2004,370,760 o the 3,508,600 acres o saltwaterwetlands along the Gul Coast were lost,more than along any other U.S. coastline(Stedman and Dahl 2008).

In general, nutrient enrichment o wetlandsresults in higher aboveground standing bio-mass (Morris 1991). However, belowgroundproduction is more critical than aboveg-round production to sustaining marshesas sea level rises. The production o rootsand rhizomes elevates the marsh sur ace atrates that can help compensate or rela-tive sea level rise. Results rom a 30-year

experiment in salt marshes in Massachusettsshow that eutrophication does not increaseorganic matter accumulation belowgroundbut instead weakens soil strength and maycause a signi cant loss in marsh elevationequivalent to about hal the average globalsea level rise rates (Turneret al. 2009).There ore, sustaining and restoring coastalemergent marshes is more likely i theyreceive ewer, not more, nutrients.

Like wetlands, other biogenic shoreline

habitats have su ered signi cant degrada-tion and loss rom nutrient enrichmentin the decades be ore the DWH oil spill.Nutrient loading can cause massive bloomso phytoplankton, microalgae and macroal-gae, which can compete with benthic seagrasses (Hugheset al. 2004, Burkholderet al. 2007) and corals (Anthonyet al. 2011)

or light and oxygen and can inter ere withoyster spat settlement on ree s (Thomsenand McGlathery 2006). Orth and vanMont rans (1990) estimated that sea grass

covered 2.47 million acres (nearly one

million hectares) o the Gul ; sea grass habi-tat losses over the past 50 years, however,have been estimated at 20 to 100 percent

or most northern Gul estuaries (Duke andKruczynski 1992). Similarly, losses o 50to 89 percent are estimated or oysters inthe Gul rom baselines ranging rom 20 to130 years ago to the present (Becket al. 2011). Coral ree s in the Gul have experi-enced coral bleaching and disease outbreaksattributed to anthropogenic stressors inthe past ew decades, resulting in losses intotal coral cover on some ree s (Knowltonand Jackson 2008). Because o the knownstress o excess nutrients on these organ-isms, we can attribute some aspect o theselosses to nutrient loading. Nutrient loading islikely to continue to increase in the comingdecades and could inter ere with success ulrestoration o coastal wetlands and subtidalbiogenic habitats o the Gul i it continuesunabated.

Dead zones in the Gul o Mexico:The consequences o hypoxiaIn large part because o nutrient loading,hypoxia (dissolved oxygen < 2 mg l-1) is agrowing problem worldwide in estuariesand coastal oceans (Rabalais 2002, Diaz andRosenberg 2008). The extent and persis-tence o hypoxia on the continental shelo the northern Gul make the Gul s deadzone the second-largest mani estation oanthropogenic coastal eutrophication in theworld (Figure 2). Systematic mapping andmonitoring o the area o hypoxia in bottomwaters began in 1985 (Rabalais 2002). Thedead zone size, as measured each year inJuly, has ranged between 40 to 22,000 km2 and averaged 16,700 km2 rom 2000 to 2007(excluding two years when strong stormsoccurred just be ore the hypoxia survey).

An Action Plan or Reducing, Mitigating,and Controlling Hypoxia in the Northern

Gul o Mexico (Mississippi River/Gul oMexico Watershed Nutrient Task Force2001) endorsed by ederal agencies, statesand tribal governments calls or a long-termadaptive strategy coupling managementactions with enhanced monitoring, mod-eling and research, and reassessment oaccomplishments and environmental indica-tors at ve-year intervals. Several modelssummarize the relationship between thenutrient loading o nitrogen and phospho-rus and the severity o the hypoxic zone

(Figure 2; Rabalaiset al. 2007) and support

1920spresent Widespreadapplication o pesticides and

ertilizers occurred on agricul-tural lands beginning in the1920s and continuing today.Photo: Willard Culver/NationalGeographic Stock


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Hypoxic Dead ZoneWhen dissolved oxygen levels reach two milligrams perliter or lessa condition called hypoxiamost slow-moving or attached animals su ocate, creating areasknown as dead zones in the bottom waters. The deadzone in the northern Gul o Mexico is nearly the largestin the world, averaging 6,700 square miles (17,300square kilometers) over the past ve years; it is secondonly to the hypoxic zone in the Baltic Sea.

Agricultural sources contribute more than 70%o the nitrogen and phosphorus delivered to theGul , versus only 9 to 12% rom urban sources.

Nitrogen66% comes rom growing crops, espe-cially corn and soy. Other sources includeatmospheric deposition (16%), urban andpopulation sources (9%), pasture and range(5%), and natural land (4%).

Phosphorus43% comes rom crops, especially cornand soy, and 37% comes rom range andpasture, particularly animal manure. Othersources include urban and populationsources (12%) and natural land (8%).

Source: Alexanderet al. 2008

The maximum area o this dead zone wasmeasured at 8,481 square miles (22,000square kilometers) during the summer o2002; this is equivalent to the size oMassachusetts.

States that run o into the GulMore than 75% o nitrogen and phosphorus runocomes rom Illinois, Iowa, Indiana, Missouri, Arkansas,Kentucky, Tennessee, Ohio and Mississippi

Study area200 km

GalvestonBay

MississippiRiver

Figure 2

Mississippi River BasinRivers, estuaries and tributaries

rom the 48 contiguous statesrun o into the Gul via theMississippi River basin. Source:USDOI and USGS 2008

Year-to-year area o Gul o Mexicohypoxia, shown in square milesNo data available or 1988 and 1989.Source: Rabalais et al. 2010

0

20101985 1990

s q u a r e m

i l e s

2000

5,000

10,000


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the key component o the management

action, which is to reduce nutrient loadingto the Gul o Mexico so that the averagehypoxic area in summer is 5,000 km2 orless by 2015. Turneret al. (2008) suggestedthat there was an increase in the oxygendemand o marine sediments arising romthe accumulation o organic matter andthat the accumulation in one year made thesystem more sensitive to nitrogen loadingthe next year. Remedial actions meant toreduce the size o the hypoxic zone mustaddress these uture increases in nutrient

loading and todays legacy o eutrophication.

La d loss alo g the Gul Coast

Coastal developmentThe population o the ve Gul Coast statesincreased by 45 percent between 1980and 2008. More than 20 million people arenow living on the Gul Coast, with coastalcounties in Texas and Florida (see boxabove) experiencing the largest population

increases (Crossettet al. 2004). Increases

in residential, commercial, industrial andagricultural development have accompa-nied this population increase, resulting inthe loss o coastal orests and wetlandsand increases in storm water runo andtransport o nutrients and sediments intothe Gul .

Channelization, levee construction anddamming have limited foodwater fowsonto the food plains, thereby suppressingthe transport, deposition and retention osediments to enrich the soils and vegeta-tion. Motivated by a desire to create morewater ront real estate with riparian access

or large boats, aggressive construction o nger channels (see photos, Page 26)took place in the mid-1950s to late 1960salong much o the coast o south Florida.The dredge-and- ll operations were o tenconducted directly over mangrove orests oroyster ree s, as illustrated in these photos.In addition to destroying critical sh habi-tats, aggressive construction in the estuaries

Figure 3

South Florida PopulationGrowth Since 1900 SouthFloridas population has grown

rom 5,000 in 1900 to a currentpopulation over ve million.

Source: Walkeret al. 1997

0

1

2

3

p o p u

l a t i o n

( m i l l i o n s )

5

4

1900 20111950

19802008 The populationo the ve Gul Coast statesincreased by 45 percent. Aboveis Panama City, FL. Photo: RayDevlin

Coastal Development in South Florida

South Florida, consisting o seven coun-ties, supported a population o only5,000 people in 1900. By 1930, a terHenry Flagler, a principal in Standard Oil,completed the Miami railway, the popu-lation had grown to more than 230,000.With this population surge came largeincreases in agriculture in the rst hal othe 20th century, with more than 55,000hectares o armland by 1943, accom-panied by the destruction o coastalmangrove orests and the Evergladeswetlands, and then large increases inresidential and urban development in thelatter hal o the 20th century. Massivefooding in the late 1940s with bur-geoning mosquito populations causedthe ederal government to build dikesaround Lake Okeechobee to providefood protection or the growing urbanareas to the south and to build mosquitoabatement ponds throughout the area.By 1950, the South Florida populationreached 720,000, primarily associatedwith migration o retirees into suburban

single- amily residences surrounded bygol courses, pools and urban centers(Walkeret al . 1997). Today the popula-tion is over ve million, representing oneo the highest growth rates in the UnitedStates rom 1900 to the present.

Because o the high rate o develop-ment, many o the unctions o theecosystems in South Florida are nolonger being per ormed. Erosion hasbecome a major problem on the coast,largely as a result o severed water andsediment transport pathways romupstate down through the Evergladesand to Miami, loss o mangroves onshore, consequences o channel dredg-ing, and impacts o subsidence causedby groundwater extraction. With sealevel rise now threatening to food allo South Florida (Figure 8), restoratione orts in this region must address a suiteo ecological issues to restore long-termsustainability and resilience o ecosys-tems and human communities.


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reduced the bay size and altered the sedi-ment dynamics o the tidal inlets and thenearby ocean beaches (Wang et al. 2011).

Compounding the rapid residential develop-ment, dredging or oil and gas extractionhas been causally linked to coastal wetlandloss in the Gul . More than 90 percent oU.S. o shore oil and gas reserves, pastproduction and present yields are in thecoastal waters o the Gul o Mexico, butthe inshore recovery peaked more than adecade ago. Large-scale e orts to slow orreverse wetland losses along the Gul beganin the early 1990s, ocused on constructiono river diversions. Such projects make upthe largest and most expensive strategy oraddressing wetland loss in the Louisianacoastal area, with uture costs possiblyreaching several billion dollars. Dredgingnavigation routes through Gul coastal wet-lands began at least 200 years ago (Davis1973), but it was the canals dredged or oiland gas recovery e orts beginning in the1930s and peaking in the 1960s (Figure 4)that had demonstrable and coastwide infu-ences on wetlands. The direct impact odredging on wetlands amounted to 1,017km2 o canals in 1990 (Britsch and Dunbar1993), with an equal area o spoil banksstacked on the adjacent wetlands (Bau-mann and Turner 1990). There is a muchlarger indirect impact rom canals and thedredged spoil deposits that is demonstrableat several temporal and spatial scales. Forexample, 1) land loss rates in the deltaicplain, in similar geological substrates, aredirectly related to dredging; 2) the amount

o land loss where dredging is low is nearzero; and, 3) the land loss rates acceler-ated and slowed when dredging rose and

slowed in the Barataria basin (Turneret al. 2007b).

The rise and all in dredging is coinciden-tal with the rise and all o wetland loss(Figure 4). Other plausible explanations

or wetland loss are related to the loss othe accumulated organic matter and plantstress accompanying an altered hydrology(Swenson and Turner 1987, Turner 1997,2004). But the act that sea level rise, soilsubsidence and the concentration o sus-

pended sediment in the river have remainedabout the same rom the 1960s to thepresent (Turner 1997, Turner and Rabalais2003) supports the conclusion that the cur-rent dominant cause o Gul wetland loss isdredging.

Dredging is regulated and authorizedthrough permits issued by state and ederalagencies, and the permitting processdoes not appear to refect the oreseeableconsequences or wetland loss. Damagethat is now evident was largely completedbe ore critical analyses o wetland impactso canal dredging were completed. Buteven today there is no coastwide restorationprogram that speci cally targets compen-sating or the direct and indirect impactso canals and spoil banks on wetland loss.Existing canals and any uture dredging andcanal construction could compromise DWHrestoration e orts i they occur within areastargeted or restoration.

1950s1960s Finger channelswere constructed over man-grove and oyster ree habitatsin South Florida. The reductionin bay size rom lling also hada substantial impact on the tidalinlets and on sediment supplyto adjacent beaches. Photos:Courtesy o Ping Wang

The rise and all indredging is coincidentalwith the rise and all o wetland loss.

1918 A canal is dredged inNew Orleans. Photo: TeamNew Orleans/U.S. Army Corpso Engineers

1951 2010


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1220001850

L a n

d a r e a

( k m

2 )

1900 1950

14

16

18

-1520001850

O u

t e r

b a r

d r e

d g

i n g

d e p

t h ( m )

1900 1950

-10

-5

0Figure 5

Land loss trends or HornIsland, a Mississippi-Alabamabarrier island (le t), comparedwith depths o shipping chan-nels dredged through the outerbars at the Horn Island Pass.Source: Adapted rom Morton2008

Figure 4

Relationship between landloss and canal density in theLouisiana coastal zone Thestudy measures land loss over

ve time periods between 1930and 2000. Source: Adapted

rom Turneret al. 2007b

020001930

L a n

d l o s s

( k m

2 )

1950 1970 1990

40

80

120

020001930

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d ( k m

2 )

1950 1970 1990

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12

The sinking coastline: unsustainable oil,gas and groundwater extractionAlthough natural subsidence processes,such as sediment compaction and down-warping o underlying crust (e.g., in theMississippi River Delta plain, Barataria Basin,and Atcha alaya Basin) are occurring alongthe coast, the withdrawals o subsur ace oiland gas are also major contributors to Gulwetland loss in some places (Kennish 2002).For example, the rates o soil compactionand eustatic sea level rise along the upperTexas coast can exceed 13 millimeters peryear (mm yr-1), while human-induced sub-sidence rates can be as high as 120 mm yr-1 (White and Tremblay 1995). In the Houston-Galveston area, withdrawal o groundwa-ter has caused up to three meters o landsur ace subsidence, with the rate o subsid-ence ranging rom 10 mm yr-1 to more than60 mm yr-1 (Gabrysch and Coplin 1990).

Beach nourishment to compensateor land loss

As sea level rises and hurricanes and otherstorms subject barrier beaches to highwave run-up and beach erosion, the land

orms can change dramatically. With risingsea level, barrier islands commonly rollover through the process o over-wash andbecome reestablished in a new locationdisplaced landward (Figures 9, 10). Thisprocess represents a natural dynamic osandy shorelines, although the greenhousegas-driven high rates o present and uturesea level rise are abnormal. So long as bar-rier islands and coastal barrier beaches arenot developed and residents do not attemptto draw permanent property lines, the roll-over o coastal barriers does not representa problem (Figures 9, 10). However, whenhouses, roads and other in rastructure andbusinesses are constructed on these mobile


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Figure 6

Detail o northern coast oGul o MexicoSee Gul overview map Page 2.See Barrier Island detail mapson Pages 3435 (Isles Dernieresand Chandeleur Islands).

DauphinIsland

Site oDWH spill

De SotoCanyon

Flower GardenBanks NationalMarine Sanctuary

Grand Isle

PascagoulaRiver

AlabamaRiver

EscambiaRiver

Atcha alayaRiver

Atcha alayaBay

Mississippi River Delta

Mississippi River

New Orleans

Baton Rouge

Isles Dernieres(see detail map on Page 34)

Houma

Biloxi

MobilePensacola

GULF OF MEXICO

Chandeleur Islands(see detail map on Page 35)

lands, then engineered hard structures suchas seawalls and jetties or so t solutions suchas beach nourishment are typically pursuedto protect the investments. Stabilizingcostal barriers under the emerging context

o accelerating rates o sea level rise andenhanced requency o intense tropicalstorms will make occupation o coastalbarriers along the Gul Coast increasinglyexpensive, environmentally damaging andpotentially too costly to maintain, especiallyon the rapidly subsiding Mississippi Delta.

Beach excavations to locate and removeburied oil and tarballs also represent physi-cal habitat disturbances that can bury andkill the invertebrate prey or shorebirds and

sur sh, but this is a brie pulse disturbancerom which recovery should occur within ayear. Removal o plant wrack composed omarsh macrophytic and sea grass materialstakes away a resource that nurtures insects,amphipods, isopods and other invertebratesthat serve as prey or shorebirds, especiallyplovers. Consequently, this interventioninto sandy beach habitats also representsdegradation o ecosystem services. Potentialimpacts on the threatened piping plover areespecially critical to assess.

Alteratio s o river systemsthat lead i to the Gul oMexicoThe watersheds in the Gul contain a range

o habitats that support biologically diverseand productive ecosystems with bothnursery and eeding grounds or ecologi-cally and economically important species(Livingst

a once and future gulf of mexico ecosystem

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