藻源性湖泛发生过程CDOM变化对水色的影响

J．LakeSci．(湖泊科学)，2015，27(4):616-622DOI10．18307/2015．0408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443nm处的吸收系数ag(443)为4.48m－1．水体黑度值(FeS浓度)呈先增大后减小的趋势，最大值0.35mmol/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，ag(443)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ag(443)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，wedevelopedalaboratoryscalemesocosmtostudytheconditionsthatfavourtheformationofblackwaterblooms．Usingwatersamplesandsedimentfromaneutrophiclake，weanalyzedthedailytransformationofphysical，biologicalandchemicalconditionsoverseveralweeks．Theresultsshowedthatatransformationofoxic-hypoxic-anoxicconditionscharacterizedtheformationoftheblackbloom．Inanaerobicconditions，chromophoricdissolvedorganicmatter(CDOM)increasedduetothepro-ductionofdegradationproductsfromdecayingalgae．CDOMreachedamaximumonday6withthevalueof4.48m－1．Theblack-ness(FeSconcentration)increasedinitially，thendecreasedtoaconstantconcentrationof0.35mmol/L．CDOMvaluesweresig-nificantlycorrelatedwiththeblacknessofwatercolor．Water-leavingradiancewassimulatedunderdifferentCDOMconditionsbyHydrolightandtransposedusingtheCIEcolormatchingfunctions．Thisshowedatransitionfromgreentobrownwhichcloselyfol-lowedtheincreaseinCDOMabsorption．ＲesultsaboveclearlyshowthatCDOMisamajorfactorleadingtotheformationofblackblooms，andcanbeusedtomonitortheirdynamicsovertime．Keywords:Blackbloom;absorptioncharacteristics;CDOM;watercolor藻源性湖泛是指湖泊富营养化