InvestigationsofchlorophyllaandprimaryproductivitywerecarriedoutintheBeringSeaalongtheBRlineandtheBSlineduringtheSecondChineseNationalArcticResearchExpeditioninthesummerof2003.Theresultsshowedthatthesurfacechlorophyllaconcentrationswere0.199～1.170μg/dm3,andtheaveragevaluewas0.723μg/dm3ontheBRline.FortheBSline,thesurfacechlorophyllaconcentrationswere0.519～4.644μg/dm3(average1.605μg/dm3)and0.568～14.968μg/dm3(average5.311μg/dm3)duringtheearlyandlatesummer,respectively.Theaveragevalueinthelatesummerwasmuchhigherthanthatintheearlysummer.Thehighvalues(morethan4.0μg/dm3)occurredatstationsoftheBSlineinthesouthernBeringStrait.Thechlorophyllaconcentrationsinthesubsurfacelayerwerehigherthanthoseinthesurfacelayer.Theresultsofthesize-fractionatedchlorophyllashowedthatthecontributionofthepicoplanktontototalchlorophyllawasthepredominanceattheearlysummerandthecontributionofthenetplanktonwasthepredominanceatthelatesummer.Thecarbonpotentialprimaryproductivitiesvariedbetween0.471and1.147mg/(m3·h)ontheBRline,withaverageratesof0.728mg/(m3·h).TheprimaryproductivitiesontheBSlineweremuchhigherthanthoseoftheBRline,rangingfrom1.227mg/(m3·h)attheearlysummerto19.046mg/(m3·h)atthelatesummer.Theresultsof1.147mg/(m3·h)ontheBRline,withaverageratesof0.728mg/(m3·h).TheprimaryproductivitiesontheBSlineweremuchhigherthanthoseoftheBRline,rangingfrom1.227mg/(m3·h)attheearlysummerto19.046mg/(m3·h)atthelatesummer.Theresultsofthesize-fractionatedprimaryproductivityshowedthatthecontributionofthenanoplanktontototalproductivitywasthepredominanceattheearlysummerandthecontributionofthenetplanktonwaspredominanceatthelatesummer.Theassimilationnumberofphotosynthesiswas0.45～2.80mg/(mg·h)inthesurveyedstations.
