Coccolith assemblages and their response to climate and surface hydrography in the Yellow Sea, Northwest Pacific, AD 1780–2011

(整期优先)网络出版时间:2016-10-20
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AstudyofcoccolithassemblagesfromaboxcorefromthecentralSouthYellowSea(SYS)wasperformedrevealingfluctuationsontheirrelativeabundance(%)thatcanberelatedtoclimaticandhydrographicchangesoverthelast230years(1780–2011).Totalcoccolithabundancesrangedfrom7.0to55.1×106coccoliths·g-1sediment.Althoughtheabundanceofdifferentspeciesvariedwidelythroughoutthecore,seventaxadominatedtheassemblage.Amongthesespecies,Gephyrocapsaoceanicawasthemostdominantspecies,anditshowedanaveragepercentageof50.1%.ThepatternofG.oceanica(eutrophicspecies)wasoppositetothatofthecombinedpercentageofBraarudosphaerabigelowiiandUmbilicosphaerasibogae(botholigotrophicspecies),indicatingthatintheYellowSea(YS),thedistributionpatternofG.oceanicamightbecharacteristicofnutrientavailability.SimilarpatternsbetweenG.oceanicaandtheSiberianHighwereobservedonaninter-decadaltimescale,indicatingthattheEastAsianWinterMonsoon(EAWM)maybeanimportantdriverofecologicalchangesintheYS.WhentheEAWMprevails,boththeYellowSeaCoastalCurrent(YSCC)andYellowSeaWarmCurrent(YSWC)strengthen,andtheincreasingnutrientavailabilityandwarmerwaterbroughtbythestrengthenedYSWCfavoreutrophicandwarm-watercoccolithophorespecies,suchasG.oceanica.Thislikelymechanismdemonstratesthatcoccolithassemblagescanbeusedasbenignandreliableproxyforclimatechangeandsurfaceoceanography.