藻源性湖泛发生过程CDOM变化对水色的影响

．，．LakeSci．(湖泊科学)，2015，27(4)：616-622DOI10．183O7／2015．0408@2015byJournalofLakeSciences藻源性湖泛发生过程CDOM变化对水色的影响李佐琛，段洪涛，申秋实，张玉超，马荣华(中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室，南京210008)摘要：利用Y-型沉积物再悬浮发生装置模拟湖泛发生过程，分析其中有色可溶性有机物(CDOM)的变化特征及其对水色的影响．结果表明，藻类死亡过程消耗大量的氧气，水中溶解氧在短时间内消失殆尽，形成厌氧环境；并同时分解产生大量CDOM，使得水中CDOM显著增多．前期阶段，CDOM浓度随时间一直升高，第6d时CDOM浓度达到峰值，CDOM在443am处的吸收系数u(43)为4．48m～．水体黑度值(FeS浓度)呈先增大后减小的趋势，最大值0．35mmo~L同样出现在第6d，整个过程中，CDOM浓度和黑度值变化趋势一致，a(43)与水体黑度呈显著正相关．利用Hydrolight和CIE颜色匹配函数模拟不同梯度的CDOM对水色的影响，发现随U(43)增大，水体颜色也逐渐由绿色转为棕色，整体向长波方向移动，水色逐渐变暗．因此，可以认为CDOM浓度变化是引起湖泛水体发黑的重要原因之一，可作为定量监测湖泛强度的指示性参数．关键词：湖泛；光学特性；CDOM；水色Thechangesofwatercolorinducedbychromophoricdissolvedorganicmatter(CDOM)duringtheformationofblackbloomsLIZuochen，DUANHongtao，SHENQiushi，ZHANGYuchao＆MARonghua(StateKeyLaboratoryofLakeScienceandEnvironment，NanjingInstituteofGeographyandLimnology，ChineseAcademyofSciences，Nanjing210008，P．R．China)Abstract：Inthisstudy，wedevelopedalaboratoryscalemesocoslTltostudytheconditionsthatfavourtheformationofblackwaterblooms．Usingwatersamplesandsedimentfromaneutrophiclake，weanalyzedthedailytransformationofphysical，biologicalandchemicalconditionsoverseveralweeks．Theresultsshowedthatatransformationofoxic—hypoxic—anoxicconditionscharacterizedtheformationoftheblackbloom．Inanaerobicconditions，chromophoricdissolvedorganicmatter(CDOM)increasedduetothepro—ductionofdegradationproductsfromdecayingalgae．CDOMreachedamaximumonday6withthevalueof4．48m～．Theblack—ness(FeSconcentration)increasedinitially，thendecreasedtoaconstantconcentrationof0．35mmol／L．CDOMvaluesweresig—nificantlyCOlTelatedwiththeblackness0fwatercolor．Water—leavingradianeewassimulatedunderdiferentCDOMconditionsbyHydrolightandtransposedusingtheCIEcolormatchingfunctions．Thisshowedatransitionfromgreentobrownwhichcloselyfol-lowedtheincreaseinCDOMabsorption．ResultsaboveclearlyshowthatCDOMisamajorfactorleadingtotheformationofblackblooms，andcanbeusedtomonitortheirdynamicsovertime．Keywords：Blackbloom；absorptioncharacteristics；CDOM；watercolor藻源性湖泛是指湖泊富营养化水体在藻类大量暴发、