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Study of colloidal phosphorus variation in estuary with salinity

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Study of colloidal phosphorus variation in estuary with salinityof,in,IN,Study,with,STUDY,study

    Study of colloidal phosphorus variation in

    estuary with salinity

    Acta0ceano1.Sin.2010.Vo1.29.NolP1725

    DOI:10.1007/s1313101000035

    http://wwwhyxb.oIg.cn

    Emaihhyxbe~263.net

    Studyofcolloidalphosphorusvariationinestuarywith

    salinity

    CHENDing.ZHENGAirongh.CHENMin'

    DepartmentofOceanographyandInstit1lteofSubtropicalOceanograph3r.XiamenUniversity

    Xiamen361005,China

    StateKeyLaboratoryofMarineEnvironmentalScience.XiamenUniversity.Xiamen361005Chilla

    Received5January2009;accepted24March2009

    ?TheChineseSocietyofoceanographyandSpringerVerlagBerlinHeidelberg2010

    Abstract

    Thevariationofcolloidalphosphoruswithsalinityinestuarywasstudiediuthispaper,whichwas

    comparedwiththoseofparti('leandtrulydissolvedphosphoruswiththepurposeoffindingouttile

    similaritiesanddifierencesbetweentheirbehaviorsintheestuary.Distributionpatternsofphospho

    rusinparticle.colloidalandtrulydissolvedphaseatdifierentsalinitiesandtheirrelationshipswith

    suspendedparticulatematterwerealsostudiedtounderstandthetransformationandtransporta

    tionofcolloida1phosphorusinestuarinearea.Theresultshowedthattheconcent~ationsofiotal

    colloidalphosphorus,organk('olloidalphosphorusandinorganiccolloida]lphosphatealldescended

    fromriver

    endtosea-end.ilhlstratingtheirterrigenoussource.Ratiosoforganictototalcolloidal phosphorusdecreasedwithsalinity'sincrement.indicatingthatorganicphosphoruswasi1~fluenced

    byscavengingprocessofcolloidmoresignificantlyascomparedwithinorganicphosphate.Bothof

    thephosphorusvariationtendenciesandtheproportionbetweenorganicandinorganicphost)horus

    incolloida1phasewassimilarwiththatintrulydissolvedphasewhiledifierentfroruthatinparticle

    phase.

    Keywords:trulydissolvedphase.colloidalphosphorus.salinity

    1IIItroduction

    Cjolloidexistswidelyinnaturalaquaticenviron

    ment.asresearchesshowthatthet'cexistalotof

    colloidalmattersnomatterillfreshwater.seawa

    terorinterstitialwaterofsedimeilt(OI'landini1990:

    MccarthyandZachara.1989;Siglcoandttelz.1981:

    KronlandSholkvitz.19771.Coiloidcaneasilyabsorb

    someradioactiveisotopes.traceelementsandorganic:

    compoundstoitssurfacewiththepropei'tyofslnal1

    grainsize,largespecificStiFf'aceareaandabundantof'

    organicfunctionalgroups.Asaresult.itplaysasig

    nificantroleinthepresentationandtraI1sD0rtatioI1of

    elementsintheoceal1.SincetileusageofCI'OSSflow

filtrationfCFF1frOlllthe1980s.colloMCallbestud

    iedseparatelyapartfronlttIOSeeolrlnlon"dissolved phasefiltratedbythe0.45nnsieve.

    Inmanyestuarineareasaildbax's.thechemi

    calbehaviorofphosphorusappea1'squitccomplicated fHydesaeta1..2004:Lineta1.,20(14:Gowenaeta1. 2002;Xiongeta1..1999;Chen.Lueta1..1997:Chen. Liaoeta1..1997)fbrtherearesignificantchangesof water)llysi(ocheI_I1icalcharacteristicstakingplacein theestuary.a,ndtransfornlatkmsortransportations amongdifferentphosphol'USformsarealsofrequent fChenLueta1..1997).ItllaS[/eenstudiedthat thereis(:loserelationshipbetweenphosI)ho~,118coucen

    trationalldsalinityinestuarineandthalassicwater.

     whichCal1beweakpositivc(leta1..2006)orneg

    tirefHydesaeta1..2(104:Go~venaeta1..2002)orof diffei?entten(1enc\rdevidedbysonlesalinityfLineta1.. 2004;Xiollgeta1..1999:C11el1.Liaoeta1.1997)in differentestuarysaridba3,s.Suspendedmattei'Call actasabufferfordissolxedphoshptlOtUS1),itsab

    sorbtionoi(tesorptionofphosphoIusandinfluencc the1)ioavailablephospllorustosoiueextent(Tanaka. 19881.Besides,colloidisconsideidasthemedium forn~d111ingtileprocessofparticlematterdecom

    poulldingtodissolvedmattel.aildislikel5'tobecomea "colloi(1alpump"ofelenlcntstransportationfHydesa eta1..20041.Howab/)ut1(colloid'srelationshipwith

    particleOl-dissolvednlatteri?theesttlaiv?Thereis

    stillUOstnd3reportsaboutthistopicathomeand abroad.

Foundationitem:TheEducationDepartmentofChinafortheplanofchiefteaclmrsinllnivel's

    ities;theNationalNatm'alScience

    FoundationofChinaforthekeyplanundeicontl'actNo90411016. CorrespoIldingauthorEmaihalzhengU,xmueel1.1(1n

    18CHENDingeta1.ActaOceano1.Sin,2010,Vo1.29,No.1,P.17-25 Inthispaper,wesetsevensitesofdifierentsalin

    itiesfrom0to30intheJiuloniangRiverandsouth

    XiamenBay.Phosphorusconcentrationsofsuspended particle,totaldissolvedphase,trulydissolvedphase andcolloidalphaseweredetectedinordertogetthe variationtendencyofcolloida1phosphoruswithsalin- ityintheJiulongjiangRiverEstuary,whichwascorn

    paredwiththoseofparticulateandtrulydissolved phosphorus,soastoknowthethesimilaritiesand differencesbetweentheirbehaviorsinestuarinearea. Moreover,phohsphorusproportionsinparticle,col

    loidalphaseandtrulydissolvedphaseandtheirre

    lationshipwithsuspendedparticularmattercontent werestudiedtofindouttheactionofcolloidonphos

    phorus'transportationandtransformationinthees. 1I746

    tuarY

    2Materialsandmethods

    2.1Studyareaandsamplecollection

    WatersamplesfromtheJiulongjiangRiverEstu- aryandsouthXiamenBayofChina(showninFig.1) werecollectedonNovember2006.Thelatitudeand longitudeofeachsite.andthesalinitiesaregivenin Table1.Cleanplasticbucketswereusedforsampling surfacewaters,whichweredippedinchromicacidmix-

    turefirst,thenwashedbyaplentyofpurewaterand rinsedbywatersampleseveraltimesbeforesampling. Salinitieswerequicklymeasuredbyasalinometerin siteandthenbyargentometryforexactitudeinthe laboratoryafterarriva1.

    IJ8O0II8.08E

    Fig.1.DiagramofsamplingsitesfromtheJiulongjiangRiverandsouthXiamenBayofChina.

    Table1.Samplingsitesandsalinity

    2.2Colloidisolationandphosphor-usdetec

    tion

    First,about500mLwatersampleofeachsalin

    itywasfilteredbyfabricestermicroholefilteringfilm

    Iporesize0.22m,beensoakedindilutehydrochlo

    ricacidfor12hwashedtoneutra1andweighedaf- terovendried(StandardizationAdministrationofthe People'sRepublicofChina,20o2)togetthesamples

    ofsuspendedparticulate::latter.Followingmethods inZhengeta1.f2002),therestlargevoluIneofwater sampleswasprefilteredthrougha0.22"mporesize

    cartridgefilterinorder'toremovesuspendedparticu

    latematterandprovidethesamplewecalledthetotal dissolvedphase(<0.22m).

    CrossflowultrafiltrationsystemfAmiconH1P10- 20,10kDamolecularmasscuto1wasusedtoisolate

    colloid,andtheenrichmentfactor(=;,

    standforthevolumesofpre.filtrationwaterandre- tentate,respectively)wasabout40.Accordingtopre- viousresearch,graindiameterofmaterialtrappedby the10kDafiltermembranewasabout25nmf?lls

    andGoldberg,1991),sothefractionpassedthrough

    themembranewastrulydissolvedphase,andthere- mainingfractionwasamixtureofthetrulydissolved phase(<10kDa)andthecolloidalphase(10kDa-0.22 m).

    Phosphorusconcentrationsinpre-filteredwater, ultrafiltrateandretentatearerepresentedbycD,cuand Crandtheconcentrationofphosophorusintheco1. 1oidalphasecanbecalculatedas:cr=Cpcu.

    CHENDingetal_ActaOceano1.Sin.,2010,Vo1.29,No.1,P.17-25 AccordingtoChineseNationalStandardMethod.in

    organicphosphate(IP)intotalandtrulydissolved phasewasdetectedbythephosphorusmolybdenum

    bluemethod.TotalphosphorusfTP1wasmeasured bypotassiumperoxydisulfateoxidization,followedby thesamemethodasIP.Andorganicphosphorus(OP) concentrationwasobtainedbythedifierenceofIP concentrationandTPconcentration.Thedetection limitwas1.4#g/din.Forsuspendedparticle.TP wasalsomeasuredbypotassiumperoxydisulfateox

    idizationmethodfStandardizationAdnfinistrationof thepeople'sRepublicofChina,2002),IPbycascade

    extractmethod(Yangeta1.,1998)andphosphorus

    molybdenumbluemethodforeachextractedphase. Calculationofrecoveriesandtheirrangeswerere

    portedinC!heneta1.f20061.

    19

    2.3Performancemesurementofcross.ul

    trafiltrationsystem

    AsmethodsdescribedinChenetal

    thecrossflowultranltrationcartridgewassequentially cleanedwith1%Micro90abluentfmadebyCole

    Parmercompany1,0.2nlo1/dm3Na0Hsolution,0.2 mol/dinHClsolutionbeforeultrafiltration.then2L milliOwaterwascirculatedinthesystemfor2h. Whilecycling,ultrafiltratethatbacktothestorage wanmixedwithretentate.After2h.theultraltrate

    andretentatewanseparatedassamplesandtheirTP andIPconcentrationsweremeasured.Comparedwith milliOwater,theincreaseofeachcomponentdur

    ingtheultraltrationprocedurewaslistedinTable2, whichshowedthattherewasnearlynoincrementof Table2.Incrementofeachcomponentinultrafiltrateandretentate(pmol/dm.)

    IPduringultraltrationwhileTPincreseda1ittle. TP'sincrementwasquiteinsignificantincomparison withTPconcentrationinsamplesfT1e41.which accountforlessthan0.13%soit'sunnecessaryto dobbbbnnb1ankcorrectionincalculation.Theblank valueofthiscrossflowultraflltrati0nsystemwas1ower thanthosereportedbefore.

    UsingthemethodsinDaieta1.f2005)with

    ethanolasprecipitationreagentandmeasuringthe turbidityofglucaninitswatersolution.twokindsof glucan.ofwhichthemolecularmassis20kDaand40 kDarespectivelywereusedtobethestandardtrac

    ingsubstance.TheapparentretentioncoefficientfRC1 andtheabsorptionlossfL)inhighpurit3,waterand

    artificialseawaterof35salinityweremeasuredrespec

    tively,showninTable3.Theglucanapparentreten

tioncoefficientsinbothhigh--puritywaterandseawa.

    terwerebetterthaninstudiesbeforefZhaoeta1., 2004;Cheneta1.,2000;Daieta1.,1998;Buesseler eta1..1996;Gustafssoneta1.1996)andtileretention molecularmassmetthevaluesignedbyinanufacturer. Theabsorptionlosseswereinthelowvaluerangeconl

    paredwiththoseinstudiesbefore(Zhaoeta1.,2004; Cheneta1.,2000;Daieta1.,1998;Buesselereta1., 1996;Gustafssoneta1.19961.Cheneta1.f2000)has evercheckedthisultrafiltrationsystemandgottheap

    parentretentioncoemcientof85%andabsorption1OSS of18%for40kDadextranonAInieonultraltration

    membraneinseawater.0urexperimentshowedthat afterithadbeenusedforalongtime.thisultrafiltra- tionsystemwasstillingoodconditionforuse. Table3.Apparentretentioncoefficientandabsorption lossofglucansonH10P1020ultrafiltration

    cartridge

    3Resultsanddiscussion

    3.1Contentanddistributionofphosphorusin watersofdifferentsanlinities

    Totalphosphorus,inorganicphosphateandor

    galliCphosphorusconcentrationsinparticle,trulydis

    solvedphaseandeolloidalphasewithdifierentsalin

    itiesareprovidedinTable4,whichindicatsthatthe concentrationsofphosphorusinparticulatephasewere highestwhileincolloidalphasetheywerelowest CHENDingeta1.ActaOceano1.Sin.,2010,Vo1.29,No.1,P.17"-25 amongthreephases.TPandIPcontentincolloidal

phasewas2.639.7#g/dmand3.14.0#g/dmre

    spectively.whileOPincolloidalphaserangedfrom belowdetectionlimitto36.5#g/dm3.ColloidalTP accountedfor9.5%44.8%ofthetotaldissolvedTP

    fincludingcolloidalandtrulydissolved).Mayerand Jarrell(1995)studiedcolloidsfromriversaMreported that,colloidalphosphorus(includingIPandOP)all- countedfor0%48%ofthetotaldissolvedTP,sug-

    gestingthesimilarratioofcolloidaltototaldissolved phophorusintheriverandintheestuary.

    Table4.Phosphoruscontentsofdifferentspeciesineveryphase Notes:BDstandsforbelowdetectionlimit

    3.2Variationtendencieso1'colloidalphospho- swithsalinityinestuary

    VariationtendenciesofcolloidalTP.IPand0P contentswithsalinityareshowninFig.2andTa

    ble5.ColloidalIPvarieslittlewithsalinityfFig.21 asdecliningslightlyformriverendtosea-end.Vari

    ationtendenciesofcolloidalTPandOPappearuni

    formwitheachother,bothofwhichgenerallydecline fromrivertosea,andtheirdeclinecurvesweremore sharplythanthoseofcolloidalIP.AsinFig.5,expo- nentialreductioncurveshowsthatcolloida1TPand OPappeartobenonconservativescavengingines

    tuarine.Thisresultcoincideswiththoseofcolloidal totalorganiccarbon(TOC),tracemetalandsomera- dioactiveisotopesvariationwithsalinityfCheneta1., 1999;Sanudowilhelmyeta1.,1996;Guoeta1.,1995, Gnoet..1994;Bennereta1..1992).Generalizing theresearchesoncolloidinthepast.GnoandSantschi

    f1997)pointedoutthatcolloidalmatterwasareactive componentwhichwastransportedfromnearshoreto offshore,beingproducedintheupperwatercolumn andthenconsumedduringitstransporttothedeep water.Thevariationtendencyofcolloidalphospho- ruscOncentrationinthisresearchsupportedtheview

    pointabove.Itcouldbeacceptedthatterrigenous inputwasthemainsourceofcolloidalphosphorusfin

    cludinginorganicphosphateandorganicphosphorus) innearshoreoftheJiulongJiangRiverestuarinearea, thetransportationofcolloidalphosphorusfromriver toseawasnotasimpledilutionprocessbutanon

    conservativescavenging.Chen,Liaoeta1.(1997)re

    portedthat,theinfluenceofsalinitytophosphorus transportaionwasmorevisibleinthelow.salinityarea wheresalinitylessthan15,andthevariationtendency approximatelybecamejdea1conservativemixturein theareawheresalinityhigherthan15.Colloidex- istsinenvironmentsthatstrictlydemandthephysical chemistryconditionssuchassalinityandPH,whilein estuarinearea,especiallythemidsalinitywaterarea

    lessthan15,thephysicochemicalpropertyofwater columnchangessharply,flocculationofcolloidalmat

    terintheseareas(Sanudo-wilhelmyeta1.,1996)leads tothegreatlyscavengingofcolloidalphosphorus.0p- positely,thescavengingprogressisnotsosignificant inthehighsalinityareaabout20to30.

    50

    0l0152O25

    Salinity

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