Download - Marine Mammals as Ecosystem Sentinels · Oceans Sustainability Unit 3 Figure 5. Gray whale migratory route along the Pacific Coast of North America. Map Created by Michelle Kinzel,

OceansSustainability Unit&

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Figure1.Graywhaleapproachesfishingpangatointeractwithhumans.Image:SanIgnacioLagoon,BajaCalifornia,2006,MichelleKinzel.

Figure2.Graywhalespyhoppingtoviewsurroundingarea.Image:MichelleKinzel,2006.

MarineMammalsasEcosystemSentinels

Scientistswhostudyclimatechangeconsidervariousfactorsandenvironmentalvariablesinordertoassessthenatureanddegreeofchangescorrelatedwithachangingclimate.Physicalgeographersandchemicaloceanographersstudychangesinoceantemperatures,increasingamountsofcarbondioxideinseawater,risingsealevelsandotherphysicalparameterswhenassessingclimatechange.

Biologistsandecologistsexaminethebehaviorpatternsandresponsesoforganismsandsearchforpossiblelinkagesorcorrelationstoclimatechangeparameters.Foreachofthesixexamplesbelow,youaretoidentifytheevidenceprovidedforeachstudy,aswellasdeterminetheinterpretationofferedthatexplainshowtheevidenceisrelatedtopotentialclimatechange.Theevidenceispresentedasexamplesofchangesinthedistributionorbehaviorofgraywhales,andtheinterpretationisahypothesisorpossibleexplanationofhowtheseobservedchangesrelatetoclimatechange.Thegraywhaleisthusconsideredtobeamajorindicatorofenvironmentalchangesintheecosystemandcanbelabeledasanecosystemsentinel.Scientistssearchforlinkagesbetweengraywhalebehaviorsandclimatechangevariablesinoceansystems.


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Figure3.Graywhaleglobaldistribution,showinghigherlatitudefeedinggroundsandlowerlatitudebreedinggroundsalongthePacificCoastofNorthAmerica.ImageCredit:"Cypron-RangeEschrichtiusrobustus"byOwnwork.LicensedunderCCBY-SA3.0viaWikimediaCommons.

Foreachofthefourstudiesyouareprovided,youneedtoidentifytheexampleofchangeindistributionorbehaviorofthegraywhales.Thesechangesrepresentthefactsorobservations.Thenusetheinformationprovidedwiththatexampletodeterminethescientificinterpretationrelatedtothewhales’change,notinghowtheobservationsorfactscouldbeattributedchangesintheatmosphere,biosphere,andhydrosphere.

ScientificStudy1)Between1967and1999,scientistsmonitoringthemigratorymovementsofwhalesattwolocationsalongthePacificCoastofNorthAmerica,GraniteCanyonandPointVicente,observeda6–8daydelayinthesouthboundmigrationofthegraywhalepopulation.TheoverallmediansightingdateshiftedfromJan.8before1980toJan.15after1980.ThisshiftinmigrationcoincideswiththeNorthPacific“regimeshift”thatoccurredinthe1970s.Aregimeshiftisdescribedasa“majorreorganizationofbiotainthePacificNorthwest”andisdirectlyrelatedtothePacificDecadalOscillation.Thewatertemperatureitselfdoesnotinfluencethe


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Figure5.GraywhalemigratoryroutealongthePacificCoastofNorthAmerica.MapCreatedbyMichelleKinzel,2007.

whales,butduetofeedbackloopsinthesystem,thechangesinthehydrosphereareaffectingthepreyavailabilityanddelayingthejourneysouthformanywhalesinthepopulation.

Figure4.ThePacificDecadalOscillation(PDO)isalong-termoceanfluctuationofthePacificOceanwithcoolandwarmphasesoscillatedevery20–30years.Image:CreativeCommonsPermission,https://sealevel.jpl.nasa.gov/science/elninopdo/pdo/

ScientificStudy2)GraywhalesexhibitedresponsesinbehaviortotheextremesofwarmElNinoandcoolerLaNinaoceanicconditionsintheirsouthernrange.Inthebreedinggrounds,therewasadeclineinthepresenceofmother-calfpairsbyhalfandadelayinpeakoccupancyfollowingthewarmElNinoof1997–1998inSanIgnacioLagoon,BajaCalifornia.ThisalterationofbehaviorwasrelatedtothechangeinpreyavailabilityforpregnantgraywhalesduringtheElNinoyear.WithreducedamountsofpreyavailablecausedbythewarmerElNinowaters,thefemalegraywhalesproducedfewercalvesandtooklongertoreachthebirthinglagoons(delayinpeakoccupancy).Thisincreasein


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temperatureandincreaseinpreycreatesaresponseinthegraywhales,anexampleofapositivefeedbackloop.

Figure6.ElNinoisadisruptionoftheocean-atmospheresystemwhichcausesoceantemperaturestoincreasebyafewdegrees.ImageCredit:JPL,http://www.jpl.nasa.gov/imagepolicy/,CreativeCommonsLicensed.

ScientificStudy3)In1999and2000,graywhaleswererecordedfeedingyear-roundinwatersoffshoreofKodiakIsland,Alaska.Duringthistime,increasingnumbersofwhaleswerefoundfeedinginareastraditionallyconsideredmigratinggrounds,aresponsetolackofpreyinthehigherlatitudesthatresultedfromtheElNino.Thislackoftraditionalpreyitems,benthicinvertebrates,causedthegraywhalestoshifttheirprimarypreyandtheirmainfeedinglocations.Becauseofchangesinthebiosphere,thegraywhaleswerefoundinnon-traditionalfeedingareas.

ScientificStudy4)Themostsurprisingandlastexampleofevidenceofashiftinthegraywhales’behaviorcamefromrecordingsofwhalecallsintheBeaufortSea,locatednorthofAlaska,inthewinterof2003–2004.Seaiceconditionsasnotedfromanalysisofsatelliteimageryfoundicecrackslargeenoughtoprovidebreathingholesforgraywhalesduringwinterconditions.ThisprovidedevidencethatthegraywhalescouldpotentiallyoverwinterinArcticconditions,astheywererespondingtothereductioninseaice.Thechangeinthehydrosphere,orreductioninseaice,elicitedadirectbehavioralresponseinthegraywhales’behavior.


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Figure7.Lifecycleofgraywhaleandmigratorymovementsrepresentedinmapformatandinatimeline.ImagebyMichelleKinzel,2015.

Allscientificstudiescitedfromthefollowingjournalarticle:

Moore,S.E.2008.“MarineMammalsAsEcosystemSentinels.”JournalofMarineMammalogy.89(3)534-540.

MarineMammalsasEcosystemSentinels—Pre-ActivityWorksheets

1)Readthesummaryarticle“GrayWhalesAsEcosystemSentinels”byMichelleKinzel,2015.

2)CompletethefollowingchartbasedontheinformationprovidedinthearticleyoureadforStep1.Forhomework,youonlyneedtocompleteallsectionsofthischart.

Tipsforcompletingthechart:

• ScientificStudy:Summarizetheinformationforeachstationnumberbyprovidingashorttitle-likenameforthescientificstudy.

! Examplesmightinclude“FeedinginJuly,”“CalfProduction,”etc.


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• Observation/Facts:Readthearticleandlistanythingthatcanbecategorizedasanobservationorfact.Lookforexampleswithdatareferences,summariesofthingsseenorrecordedandexamplesofscientificevidence.

! SeeExamplebelowrelatedtoClimateChange

• InterpretationofObservation:Theseareoftenreferredtoasahypothesisandofferanexplanationfortheobservationsandfacts.Thesearealsofactual,butcoverabiggerpicturesummaryoroverarchingdescriptionoftheinformationpresented.Keywordsthatindicateastatementisaninterpretationcouldinclude“coincidedwith,”“attributedto,”“relatedto,”etc.

! SeeExamplebelowrelatedtoClimateChange• LifeCycleMostAffected:Determinefromthesummaryprovidedwhichlifecycleis

affected,migration,feedingorbreeding/calving.

ExampleofScientificStudy,ObservationsandInterpretation.Usethisexampletounderstandhowtoidentifyobservations,factsandinterpretthem.

Figure7.Climatechangestudyexamplesshowingeffectsonecosystemsandspecies.


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ScientificStudy:ClimateChangeinOceansAffectingPolarBears

Facts:1)Oceantemperatureshaveincreased.

2)Reflectiveicedisappears,anddarkerwatersabsorbmoreheat.

3)Arcticseaicemeltsastemperaturesriseinhydrosphereandatmosphere.

4)ewerpolarbearcubsaresurviving.

InterpretationofObservation:Thereducedpolarbearcubsurvivalisattributedtofoodshortagescausedbyreductioninhabitatfrommeltingseaice.Thisisanexampleofanegativefeedbackloop.

Question:Howdochangesinthephysicalenvironmentaffectthebiology(reproductivesuccess)ofpolarbearsintheArctic?


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Table1.Completethistablebasedoninformationfromthearticle.

ScientificStudy/Station

NumberObservation/Facts

InterpretationofObservation/CausalFactors

(Scientificreasonrelatedtoclimatechange)

LifeCycleMost

Affected;Feeding,Migration

orBreeding

1

2


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ScientificStudy/Station

NumberObservation/Facts

InterpretationofObservation/CausalFactors

(Scientificreasonrelatedtoclimatechange)

LifeCycleofGrayWhaleMost

Affected;Feeding,Migration

orBreeding

3

4

Question:Whatphysical(hydrosphericoratmospheric)/environmentalandbiologicalfactorsaffectgraywhales?


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Question:Howdothesefactorsaffectthebehaviorofthegraywhale?Arethesedirectorindirectinfluences?

3)Labelthefollowingmapwithscientificstudynumbers.Usethearticle“MarineMammalsAsEcosystemsSentinels”todeterminewhichgeographiclocationcorrelateswithwhichscientificstudy,1–4.Placethenumberofthescientificstudyonthemapinthetextboxofthecorrectgeographiclocation.

Figure8.RangeofeasternNorthPacificgraywhales,depictingcoastalstudysitesfromwintering/breedingareasoffshoreofMexico,summering/feedingareasextendingfromthePacificNorthwesttoAlaska.MapImageCreatedbyMichelleKinzel,GoogleEarth,2015.

Download - Marine Mammals as Ecosystem Sentinels · Oceans Sustainability Unit 3 Figure 5. Gray whale migratory route along the Pacific Coast of North America. Map Created by Michelle Kinzel,

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