简介：

简介：OnthebasisoftheresearchofDObudgetorkineticsinshrimppond,themaininfluenceprocessofDOanditsseasonalvariationsarequantitativelydescribedthroughredividingthebudgetprocessandmodifyingthequantitativemethodoftheprocess.Thepercentagesofoxygendemandofvariousprocessesinthetotaloxygendemandaredifferentinshrimpcultivationseasons.Itisshowedthatthedissolvedoxygendemandofmini-organismsisthemajoraffectedfactorofDOinthisenvironmentandapproximatelyaccountsfor64.1～74.1%ofthetotaloxygendemand.Intheearlyperiodofshrimpculture,thedissolvedoxygendemandofallotrophicbacteriadegradingorganicmattersismuchlowerthanthatofphytoplanktonrespiration.Butinthemidterrnandlaterperiod,itisabout50%ofthetotaloxygendemandbecauseofthehigherwatertemperatureandmoreseriousself-pollution.Thedissolvedoxygendemandofsedimentislowerandjust19.1～28.8%,whilethepercentageofshrimpoxygendemandislower.TheeffectofphytoplanktononDOinshrimpculturingwaterhasdualism.Oneistheoxygenproducingprocessofphotosynthesisandtheotheristheoxygenconsumptionprocessofrespiration.Itisestimatedthatthedissolvedoxygendemandofphytoplanktonrespirationisapproximatelyone-fifthoftheoxygenproducedbyphotosynthesisundernormalilluminationconditions.Thedissolvedoxygendemandofallotrophicbacteriadegradingorganicmattersandthetotaloxygendemandofsedimentincrease4timesand1.7timesrespectivelyfromtheearlyperiodtothemidtermandlaterperiod.Obviously,theDOofculturingwatercanbealsogreatlyimprovedbycontrollingtheselfpollutionoforganicmattersduringshrimpculture.

简介：

简介：InordertodeterminetherelativeagingstatusofupwelledorverticallymixedwaterinthenorthernTaiwanStrait,arecentlydevelopedmethodofcalcularingthedegreeofnutrientconsumption(DNC)wasemployed.Upwellingwasdetectedatawaterdepthofabout75minsummer.Bottomwatersintheaphoriczoneandnewly-upwelledwatersintheeuphoriczonewerefoundtobelowintermsoftheirDNC.Ingeneral,alowDNCwasnotedalongsidetheothertraditionalupwellingindicators,suchaslowertemperatureanddegreeofoxygensaturation,buthighersalinity,apparentoxygenutilization,nutrientcontentsandchlorophyll-a.Enhancedverticalmixing,butwithoutanapparentupwellingsignal,wasdetectednearthesamelocationinwinter.