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OceansSustainability Unit&
MarineMammalsasEcosystemSentinels
Scientistswhostudyclimate
changeconsidervariousfactors
andenvironmentalvariablesin
ordertoassessthenatureand
degreeofchangescorrelated
withachangingclimate.
Physicalgeographersand
chemicaloceanographers
studychangesinocean
temperatures,increasing
amountsofcarbondioxidein
seawater,risingsealevelsand
otherphysicalparameterswhen
assessingclimatechange.
Figure1.Graywhaleapproachesfishingpangatointeractwithhumans.
Image:SanIgnacioLagoon,BajaCalifornia,2006,MichelleKinzel.
Biologistsandecologistsexaminethebehaviorpatternsandresponsesoforganismsandsearch
forpossiblelinkagesorcorrelationstoclimatechangeparameters.Foreachofthesixexamples
below,youaretoidentifytheevidenceprovidedforeachstudy,aswellasdeterminethe
interpretationofferedthatexplainshowtheevidenceisrelatedtopotentialclimatechange.
Theevidenceispresentedasexamplesofchangesinthedistributionorbehaviorofgray
whales,andtheinterpretationisahypothesisorpossibleexplanationofhowtheseobserved
changesrelatetoclimatechange.Thegraywhaleisthusconsideredtobeamajorindicatorof
environmentalchangesintheecosystemandcanbelabeledasanecosystemsentinel.
Scientistssearchforlinkagesbetweengraywhalebehaviorsandclimatechangevariablesin
oceansystems.
Figure2.Graywhalespyhoppingtoviewsurroundingarea.Image:MichelleKinzel,2006.
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OceansSustainability Unit&
Figure3.Graywhaleglobaldistribution,showinghigherlatitudefeedinggroundsandlowerlatitudebreeding
groundsalongthePacificCoastofNorthAmerica.ImageCredit:"Cypron-RangeEschrichtiusrobustus"byOwn
work.LicensedunderCCBY-SA3.0viaWikimediaCommons.
Foreachofthefourstudiesyouareprovided,youneedtoidentifytheexampleofchangein
distributionorbehaviorofthegraywhales.Thesechangesrepresentthefactsorobservations.
Thenusetheinformationprovidedwiththatexampletodeterminethescientificinterpretation
relatedtothewhales’change,notinghowtheobservationsorfactscouldbeattributed
changesintheatmosphere,biosphere,andhydrosphere.
ScientificStudy1)Between1967and1999,scientistsmonitoringthemigratorymovementsof
whalesattwolocationsalongthePacificCoastofNorthAmerica,GraniteCanyonandPoint
Vicente,observeda6–8daydelayinthesouthboundmigrationofthegraywhalepopulation.
TheoverallmediansightingdateshiftedfromJan.8before1980toJan.15after1980.Thisshift
inmigrationcoincideswiththeNorthPacific“regimeshift”thatoccurredinthe1970s.Aregime
shiftisdescribedasa“majorreorganizationofbiotainthePacificNorthwest”andisdirectly
relatedtothePacificDecadalOscillation.Thewatertemperatureitselfdoesnotinfluencethe
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OceansSustainability Unit&
whales,butduetofeedbackloopsinthesystem,thechangesinthehydrosphereareaffecting
thepreyavailabilityanddelayingthejourneysouthformanywhalesinthepopulation.
Figure4.ThePacificDecadalOscillation(PDO)isalong-termoceanfluctuationofthePacificOceanwith
coolandwarmphasesoscillatedevery20–30years.
Image:CreativeCommonsPermission,
https://sealevel.jpl.nasa.gov/science/elninopdo/pdo/
ScientificStudy2)Graywhalesexhibited
responsesinbehaviortotheextremesofwarmEl
NinoandcoolerLaNinaoceanicconditionsin
theirsouthernrange.Inthebreedinggrounds,
therewasadeclineinthepresenceofmother-calf
pairsbyhalfandadelayinpeakoccupancy
followingthewarmElNinoof1997–1998inSan
IgnacioLagoon,BajaCalifornia.Thisalterationof
behaviorwasrelatedtothechangeinprey
availabilityforpregnantgraywhalesduringtheEl
Ninoyear.Withreducedamountsofprey
availablecausedbythewarmerElNinowaters,
thefemalegraywhalesproducedfewercalves
andtooklongertoreachthebirthinglagoons
(delayinpeakoccupancy).Thisincreasein
Figure5.GraywhalemigratoryroutealongthePacificCoastofNorth
America.MapCreatedbyMichelleKinzel,2007.
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OceansSustainability Unit&
temperatureandincreaseinpreycreatesaresponseinthegraywhales,anexampleofa
positivefeedbackloop.
Figure6.ElNinoisadisruptionoftheocean-atmospheresystemwhichcausesoceantemperaturesto
increasebyafewdegrees.ImageCredit:JPL,http://www.jpl.nasa.gov/imagepolicy/,CreativeCommons
Licensed.
ScientificStudy3)In1999and2000,graywhaleswererecordedfeedingyear-roundinwaters
offshoreofKodiakIsland,Alaska.Duringthistime,increasingnumbersofwhaleswerefound
feedinginareastraditionallyconsideredmigratinggrounds,aresponsetolackofpreyinthe
higherlatitudesthatresultedfromtheElNino.Thislackoftraditionalpreyitems,benthic
invertebrates,causedthegraywhalestoshifttheirprimarypreyandtheirmainfeeding
locations.Becauseofchangesinthebiosphere,thegraywhaleswerefoundinnon-traditional
feedingareas.
ScientificStudy4)Themostsurprisingandlastexampleofevidenceofashiftinthegray
whales’behaviorcamefromrecordingsofwhalecallsintheBeaufortSea,locatednorthof
Alaska,inthewinterof2003–2004.Seaiceconditionsasnotedfromanalysisofsatellite
imageryfoundicecrackslargeenoughtoprovidebreathingholesforgraywhalesduringwinter
conditions.ThisprovidedevidencethatthegraywhalescouldpotentiallyoverwinterinArctic
conditions,astheywererespondingtothereductioninseaice.Thechangeinthehydrosphere,
orreductioninseaice,elicitedadirectbehavioralresponseinthegraywhales’behavior.
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OceansSustainability Unit&
Figure7.Lifecycleofgraywhaleandmigratorymovementsrepresentedinmapformatandinatimeline.Image
byMichelleKinzel,2015.
Allscientificstudiescitedfromthefollowingjournalarticle:
Moore,S.E.2008.“MarineMammalsAsEcosystemSentinels.”JournalofMarineMammalogy.
89(3)534-540.
MarineMammalsasEcosystemSentinels—Pre-ActivityWorksheets
1)Readthesummaryarticle“GrayWhalesAsEcosystemSentinels”byMichelleKinzel,2015.
2)Completethefollowingchartbasedontheinformationprovidedinthearticleyoureadfor
Step1.Forhomework,youonlyneedtocompleteallsectionsofthischart.
Tipsforcompletingthechart:
•
ScientificStudy:Summarizetheinformationforeachstationnumberbyprovidinga
shorttitle-likenameforthescientificstudy.
! Examplesmightinclude“FeedinginJuly,”“CalfProduction,”etc.
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OceansSustainability Unit&
•
Observation/Facts:Readthearticleandlistanythingthatcanbecategorizedasan
observationorfact.Lookforexampleswithdatareferences,summariesofthingsseen
orrecordedandexamplesofscientificevidence.
! SeeExamplebelowrelatedtoClimateChange
• InterpretationofObservation:Theseareoftenreferredtoasahypothesisandofferan
explanationfortheobservationsandfacts.Thesearealsofactual,butcoverabigger
picturesummaryoroverarchingdescriptionoftheinformationpresented.Keywords
thatindicateastatementisaninterpretationcouldinclude“coincidedwith,”“attributed
to,”“relatedto,”etc.
•
! SeeExamplebelowrelatedtoClimateChange
LifeCycleMostAffected:Determinefromthesummaryprovidedwhichlifecycleis
affected,migration,feedingorbreeding/calving.
ExampleofScientificStudy,ObservationsandInterpretation.Usethisexample
tounderstandhowtoidentifyobservations,factsandinterpretthem.
Figure7.Climatechangestudyexamplesshowingeffectsonecosystemsandspecies.
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OceansSustainability Unit&
ScientificStudy:ClimateChangeinOceansAffectingPolarBears
Facts:1)Oceantemperatureshaveincreased.
2)Reflectiveicedisappears,anddarkerwatersabsorbmoreheat.
3)Arcticseaicemeltsastemperaturesriseinhydrosphereandatmosphere.
4)ewerpolarbearcubsaresurviving.
InterpretationofObservation:Thereducedpolarbearcubsurvivalisattributedtofood
shortagescausedbyreductioninhabitatfrommeltingseaice.Thisisanexampleofanegative
feedbackloop.
Question:Howdochangesinthephysicalenvironmentaffectthebiology(reproductive
success)ofpolarbearsintheArctic?
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OceansSustainability Unit&
Table1.Completethistablebasedoninformationfromthearticle.
Scientific
Study/Station
Number
1
2
LifeCycle
Most
InterpretationofObservation/Causal
Affected;
Factors
Feeding,
(Scientificreasonrelatedtoclimate
Migration
change)
or
Breeding
Observation/Facts
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OceansSustainability Unit&
Scientific
Study/Station
Number
3
4
LifeCycle
ofGray
Whale
InterpretationofObservation/Causal
Most
Factors
Affected;
(Scientificreasonrelatedtoclimate
Feeding,
change)
Migration
or
Breeding
Observation/Facts
Question:Whatphysical(hydrosphericoratmospheric)/environmentalandbiologicalfactors
affectgraywhales?
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OceansSustainability Unit&
Question:Howdothesefactorsaffectthebehaviorofthegraywhale?Arethesedirector
indirectinfluences?
3)Labelthefollowingmapwithscientificstudynumbers.Usethearticle“MarineMammalsAs
EcosystemsSentinels”todeterminewhichgeographiclocationcorrelateswithwhichscientific
study,1–4.Placethenumberofthescientificstudyonthemapinthetextboxofthecorrect
geographiclocation.
Figure8.RangeofeasternNorthPacificgraywhales,depictingcoastalstudysitesfromwintering/breedingareas
offshoreofMexico,summering/feedingareasextendingfromthePacificNorthwesttoAlaska.MapImageCreated
byMichelleKinzel,GoogleEarth,2015.
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