Vertical variation of pelagic ciliate communities in the western Arctic Ocean

Abstract

The verticaldistributionandstructureofpelagicciliatecommunitieswereinvestigatedat32stations (westernArcticOcean)inasummersea-icereductionregionfromAugust1toSeptember10,2012.The distributions ofspeciesnumber,abundance,biomass,dominantspeciesnumberandabundance,and structural diversityindicesshowedclearverticaltrendsassociatedwithverticalchangesinthewater column. Inaddition,verticalpatternsincommunitystructureaccuratelyreflected thoseenvironmental conditions. Multivariatecorrelationanalysisdemonstratedthatverticalvariationinciliatecommunities wassignificantly relatedtoaseriesofenvironmentalvariables.Communitystructureparameters, especially Shannondiversity(H0) andMargalefrichness(D), showedstrongrelationshipswithvertical changes inchlorophyll a and mightprovidebetterpredictorsinfuturestudies.Furthermore,hetero- trophic andmixotrophicassemblagesbothdemonstratedclearverticaldistributionpatterns,and microzooplanktonhaveshownsignificantly relationshipwithchlorophyll a. Theseresultsprovidebasic data onverticalvariationinciliatecommunitiesinthewesternArcticOceanandhaveconsiderable potentialtounderstandhowpelagicciliatesstructuredinwatercolumn.