MarineConserva,onScience&PolicyCurriculum–2012,2015DeeringEstate.Allrightsreserved.1
FocusQuestionWhat isthe intertidalzone?Whatorganisms live inthishabitatandwhat challengesdotheyface?Whatisafoodchainandwhatorganismsoftheintertidalzoneareinterconnected?
ObjectivesStudents will explore the intertidal zone and discover some of the unique qualities of thisecosystem.Studentswilllearnto:
• Identifythefoursubzonesoftheintertidalzone.• Identifysomeoftheorganismsthatliveinthishabitatandthechallengestheyface.• Describeafoodchainandelaborateonefoundintheintertidalzone.
This will be a project-based activity in which students will discuss the interconnectedness oforganismsandthehabitatsinwhichtheylive.
BackgroundTherhythmicriseandfalloftheocean surface isduemostlytothepull exertedonthewaterbythemoon’sgravity.Thisdailyfloodinganddrainingexposesauniquehabitatalongthecoastscalledtheintertidalzone.Theintertidalzone,alsoknownasthelittoralzone,istheareaalongtheshoreofmarineenvironmentsthat isexposedtotheair in lowtideandfloodedbytheseawaterduringhightide.
Theintertidalzonecanbedivided intofoursubzones,includingthesprayzone,thehightide zone,themiddletidezone,andthe lowtidezone.Thesprayzone,orsupratidal zone, ismoreofaterrestrialenvironment,asit liesabovethespringhightide lineand isonlyfloodedduringstormsurgesorotherextremeweatherevents.Whilethiszone receiveswaves splashand wind-blown spray, organisms here must be able to cope with exposure to air, heat,freshwaterfromrain,andpredators likeseagulls.Someorganismsthatmakethiszonetheirhabitatincludebarnacles,aswellaslandcrabs,seagulls,possiblyevenraccoonsandseals.
Just lower than the spray zone, the high intertidal zone, as the name implies, is onlyflooded during high tide, and is exposed to the air for the longest amounts of time. Thisexposuremeans thatmarineorganisms riskdesiccation, or lossofwater, andmustadaptbyhiding or clamming up, which means sealing off their shell to conserve moisture. Marineorganismsthathaveadaptedtowithstandthisexposure includered,brownandgreenalgae,hermitcrabs,limpets,andsomesnailsandwhelks.
Themiddleintertidalzone,alsocalledthelowermid-littoralzone,isgenerallysubmerged,exceptforbriefperiodsduringlowtide.Organismsthatthriveinthiszonehaveadaptedtotheturbulenceofthedailytidalrhythms,andincludeseastars,snails,barnacles,anemones,crabs,sealettuce,andmussels.
The low intertidal zone isusuallyunderwater,only exposed to theairwhen the tide isunusuallylow.Organismsthatliveinthiszonearenotwelladaptedtolongperiodsofdryness
MarineConservationScience&Policy:IntertidalZone
GradeLevel:
4th-12th
SubjectAreaScienceBiologyDuration1.5Hrs
BodyofKnowledgeLifeScienceNatureofScience
BigIdeaOrganizationandDevelopmentofLivingOrganisms.ThePracticeofScience
StandardsSC.1.L.17.1Recognizethatallplantsandanimals,includinghumans,needthebasicnecessitiesofair,water,foodandspace.SC.4.L.17.2TracetheflowofenergyfromtheSunasitistransferredalongthefoodchainthroughtheproducersandtheconsumers.SC.7.L.17.1Explainandillustratetherolesandrelationshipsamongproducers,consumers,anddecomposersintheprocessofenergytransferinafoodweb.SC912.L.17.9Useafoodwebtoidentifyanddistinguishproducers,consumersanddecomposers.
Benchmarks:
MarineConserva,onScience&PolicyCurriculum–2012,2015DeeringEstate.Allrightsreserved.2
Backgroundorextremetemperatures.Someorganismsthatmaybefoundinthiszoneincludeabalone,seaurchins,seastars,brownseaweed,seacucumber,sponges,shrimp,surfgrass,tubeworms,andsomesmalloctopusspecies.
Particularlyalong rockyshores,tidepools canform inthe intertidal zones,areasof lowdepression that retain seawater as the tide recedes. Tide pools can range from shallow todeep,andcanbefoundinallsubzonesoftheintertidalzone.Becausethewatercanevaporate,tide pools threaten inhabitants with wild changes in salinity, oxygen and temperatures, andexposuretotheswelteringsunandpredators.Despitethechallenges,manycreatures canbefoundintidepools,includingseaanemones,starfish,barnacles,hermitcrabs,andevenfish.
This zone forms an extreme environment for four particular reasons: providing onlyintermittently the supply ofwater whichmarine organisms need to survive; poorly adaptedanimals canbedislodgedandwashedawayby the intensewaveactionalong the shore; thehighexposuretothesuncausesanextremerangeoftemperaturesfromnearboilingtoalmostfreezing;andamuchhigher salinityas seawater left inpools evaporates leavingbehind saltdeposits.
While the intertidal zone poses many challenges to organisms trying to cope, it alsoprovidesmanyadvantagestothoseabletoadapt.Therelentlesswaveaction,thoughabrasive,also constantlysuppliesthe zonewithfreshnutrientsandoxygen.Therockyprotrusionsalsoprovideallsortsofnooksandcranniesthatmakeperfecthidingplacesandsurfacestoclingto.Thesebenefits also includeplentiful sourcesof food,as theabundant sunlightalso supportsmanyalgaeandintertidalplantsthatformthebaseofarichfoodchain.
Afoodchainisagroupoforganismlinkedintheorderofthefoodtheyeat,startingwithprimary producers like plants and algae andmoving up through consumers, including prey,predators, and ending with decomposers. A foodweb can connect many food chains anddemonstratetheinterconnectionsbetweenorganisms.
Intheintertidalzone,thefoodchainbeginswithphytoplankton,microorganismsthatusephotosynthesis to create energy from the sun. These are usually consumed by zooplankton,whichinturniseatenbymussels,barnaclesorotherinvertebrate.Barnaclesareusuallyeatenbywhelks,atypeofsnailthatinturnispreyeduponbyseastars.Whileseastarsareneartheverytopofthefoodchain,theycanbestillbegobbledupbyaseagulloraseaotter.Whenthehighest predator, such as a gull or a sea otter, dies, its body is consumed by decomposers,animals that break down dead tissues and wastes. Sea urchins are common intertidal zonedecomposers,andastheycanbeeatenbyseastars,thefoodchaincanbelinkedintothefoodweb. In thismanner, the foodwebdisplaysnot just the “who eatswhat”,buthighlights thecomplexinteractionsandinterconnectednessofallorganismsandtheirenvironment.
SupplementalResources“FoodWeb.”NationalGeographicEducation.http://education.nationalgeographic.org/encyclopedia/food-web/
“IntertidalZone.”BBCNature.http://www.bbc.co.uk/nature/habitats/Intertidal_zone
“PointReyesIntertidalandSubtidalZones.”NationalParkService.http://www.nps.gov/pore/learn/nature/intertidal.htm
Vocabulary:
IntertidalZone:Theareaalongthecoastalshoresthatareexposedandfloodedalternatelybytheoceantides.
SprayZone:Theareajustabovethetidelinethatstillreceivessplashfromwindandwaves.
HighIntertidalZone:Theshoreareaonlyfloodedbyhightide,exposingitsmarineorganismstotheelements.Desiccation:Dryingoutorlossofwater.
MiddleIntertidalZone:Theshoreareagenerallysubmergedbutstillexposeddailyduringlowtide.
LowIntertidalZone:Theshoreareaisonlyexposedduringextremelowtides,hostingorganismsthatarenotwelladaptedtodrynessorextremetemperatures.
FoodChain:Agroupoforganismslinkedintheorderofthefoodtheyeat,startingwithprimaryproducersandcontinuingthroughconsumersandeventuallytodecomposers.
FoodWeb:Thenaturaloverlappinginterconnectionsbetweenfoodchainsinanecosystem.
PrimaryProducers:Organismsthatusephotosynthesistoconvertenergyfromthesunintonutrients,formingthebaseofmostfoodchains.
Consumers:Organismsthatneedtoeatotherorganismsfornutrients,thesecanbedividedintoherbivores,carnivores,andomnivores.
Decomposers:Organismsthatconsumeorganicmaterial,includingdeadtissuesandwastes,breakingdownnutrientsandreturningthemtoproducers.
MarineConserva,onScience&PolicyCurriculum–2012,2015DeeringEstate.Allrightsreserved.3
Materials• Chalkboardormarkerboardorlargebutcherpaper• Chalk,dryerasemarkerorothermarker,dependingonaboveavailability• Tape• Indexcards(orsimilarsizedpiecesofpaper)• Crayons,markers,orcoloredpencils• Pensorpencils• Specimensfromtheintertidalzoneorbooks,magazinesorprintouts,orinclude
photosinadatashowofanimalsfromtheintertidalzoneifavailable)
Procedure
1. Writethenamesofthefourinter,dalzonesontheboardorbutcherpapertocreatefourcolumns.
2. Dividethestudentsintofourgroupsandassigneachgrouponeofthefourzones.3. Haveeachgroupcompletethefollowingontheindexcards:
-1carddescribingtheirassignedzoneincludingphysicalfactorsthataffectthehabitat(i.e.turbulence,sunexposure,etc.)-Severalcardsdemonstra,ngsomeoftheorganismsthatliveintheirassignedzone,eachcardshouldfeature:thenameoftheorganism,whattheyeat,anyspecialfeaturesthathelpthemadapttotheinter,dalzone,andadrawingoftheanimal.
4. Haveeachgrouppresenttheirzoneandorganisms,tapingtheircardsintheappropriatecolumn.
5. Onceallzonesarepresented,askstudentstohelpconnectthemalltoformafoodwebbydrawingarrowsfromproducerstoconsumers,preytopredator.Ifthereisspace,drawtheSun,waterandbubbles(toindicateoxygen)andincludetheminthefoodweb.Encouragediscussionontheinterconnectednessandinterdependenceoforganismsandtheirenvironment.Wheredohumansfitin?Whatwouldhappenifonetypeoforganismdisappeared?
WorksheetAnswerKey
1. Sprayzone2. Highintertidalzone3. Middleintertidalzone4. Lowintertidalzone5. Answerswillvary,mayinclude(butarenotlimitedto):
Producers-kelp,bladderwrack,spiralwrack,sawwrackConsumers-seaurchins,rockcrabs,sunflowerstars,barnacles,hermitcrabsDecomposers-seaslugs,bacteria,fungi,
IntertidalZone:Theareaalongthecoastalshoresthatareexposedandfloodedalternatelybytheoceantides.Thiszonecanbedividedintofoursubzones,includingthesprayzone,andthehigh,midandlowintertidalzones.FoodChain:Agroupoforganismslinkedintheorderofthefoodtheyeat,startingwithprimaryproducersandcontinuingthroughconsumersandeventuallytodecomposers.FoodWeb:Thenaturaloverlappinginterconnectionsbetweenfoodchainsinanecosystem
Havestudentsreplytothefollowingpromptintheirsciencejournal:Thefoodwebisanimportantconceptforallofustoknow.Writeanexplanationofthefoodwebthatwouldhelpyouryoungerbrotherorsisterunderstand.
Havestudentscompletetheintertidalworksheetafterclass.Havestudentswriteareflectionparagraphimagingwhatwouldhappenifoneofthelinksofthefoodweb(i.e.phytoplankton)werecompletelyeliminated.Howwouldthataffectotherorganisms?
ExtensionActivity:
Assessment:
Vocabulary:
ProgramPartner:
MarineConserva,onScience&PolicyCurriculum–2012,2015DeeringEstate.Allrightsreserved.4
MSCP
TheIntertidalZone
TheInter,dalZone
1.
2.
3.
4.
Thiszoneisonlydryduringextremelow,des,hos,ngorganismsthatarenotwelladaptedtoairexposure.
Thiszoneisonlyfloodedduringhigh,de,exposingorganismstothesunandairforover12
hoursaday.
Thiszoneliesjustabovethe,deline,receivingsprayfrom
windandwaves.
Thiszoneismostlysubmergedbutisdraineddailybytheturn
oflow,de.
Writeinthenamesofthesubzonesoftheinter1dalzoneandmatchthemwiththeirdescrip1on.
Afoodwebisachartthatconnectsorganisms,showingtheinterconnec,onsandwhoeatswhatinanecosystem.MostsystemsbeginwithprimaryproducersthatusephotosynthesistoconvertenergyfromtheSunandcreatenutrients.Consumersareorganismsthatneedtoeatotherorganismsfornutrients,andthesecanbedividedintoherbivoresandcarnivores.Decomposersareorganismsthatconsumeorganicmaterial,includingdeadtissuesandwastes,breakingdownnutrientsandreturningthemtoproducers.
5.Usingtheabovediagramandyourknowledge,writeoneorganismfromtheintertidalzonethatfitsineachcategoryofthefoodweb:
SunProducers Consumers Decomposers
_______________________________________ ____________________
