• 关键词：三维荧光  溶解性有机质  富营养化  藻类  沉积物

• 基金项目：国家自然科学基金项目(No.41403094,41430743,41261140337)

• 冯伟莹
• 1. 北京师范大学水科学研究院, 北京 100875;2. 中国环境科学研究院环境基准与风险评估国家重点实验室, 北京 100012

• 朱元荣
• 中国环境科学研究院环境基准与风险评估国家重点实验室, 北京 100012

• 吴丰昌
• 中国环境科学研究院环境基准与风险评估国家重点实验室, 北京 100012

• 张旭
• 1. 中国环境科学研究院环境基准与风险评估国家重点实验室, 北京 100012;2. 南昌大学资源环境与化工学院, 南昌 330031

• 张琛
• 中国环境科学研究院环境基准与风险评估国家重点实验室, 北京 100012

• 摘要：利用三维荧光光谱(3DEEM)-平行因子分析(PARAFAC)技术,通过野外现场调查和室内模拟实验,分析富营养化湖泊(太湖)水体溶解性有机质(DOM)组成结构、分布规律及其来源,进一步研究藻类和水生植物残骸腐烂分解以及沉积物释放对水体DOM荧光组成特征的影响.结果表明:1太湖水体各个湖区DOM主要以类色氨酸物质(T₁、T₂峰)为主,竺山湾还存在类腐殖质和类富里酸物质,其荧光指数(f_450/500)为1.53±0.06,接近陆源f_450/500值(1.4),DOC浓度全湖最高((7.13±2.45) mg·L^-1),兼具陆源与生物来源的双重特性.2太湖藻类DOM组成丰富,出现了7种荧光组分,主要为类腐殖质、类富里酸和类蛋白物质(包括类色氨酸和类酪氨酸),藻类腐烂分解后,紫外区类色氨酸T₂峰和类酪氨酸B₂峰消失,其他类蛋白物质和部分易降解的类富里酸物质向水体中释放,其中A峰和C峰所代表的类富里酸物质降解率较高,分别降解了70.3%和41.0%.3水生植物DOM以类腐殖酸物质为主,其残骸腐烂分解后DOM由陆源类腐殖质向类腐殖酸物质转化.4沉积物DOM出现了5类荧光峰,兼具外源污染的类富里酸荧光C峰和A峰,同时含有生物来源的B₁、B₂、T₂类蛋白荧光峰,随其降解时间的增长,T₂荧光峰消失,B₁、B₂荧光物质降解率分别高达86.5%和82.5%,而C峰和A峰分别上升25.1%和1.5%,沉积物降解过程中大量类蛋白物质向上覆水体中释放,同时部分类蛋白物质向着更稳定的类富里酸物质转化.因此,外源输入和内源负荷(藻类和水生植物残骸腐烂分解以及沉积物释放等)对湖泊水体DOM组成结构以及富营养化过程具有重要影响.

• Abstract：Three-dimensional excitation-emission matrix fluorescence spectra (3DEEM) and parallel factor analysis (PARAFAC) were applied to investigate the fluorescence properties of dissolved organic matter (DOM) from overlying water in Tai Lake, China. The fluorescent characteristics of DOM from algae, aquatic plants, and sediments were further analyzed by simulation. Influences of DOM release from algae, aquatic plants, and sediments on the fluorescent characteristics of DOM in overlying water were investigated. DOM in overlying water of Tai Lake was primarily tryptophan-like substances (T₁and T₂ peaks). DOM in overlying water from Zhushan Bay also consisted humic and fulvic acids, for which the fluorescent index (f_450/500) was 1.53±0.06. This value was similar to that of terrigenous organic matter. Therefore, sources of DOM in overlying water from Zhushan Bay were derived from both autouthanous and allochthonous organic matter. The fluorescent characteristics of DOM indicated that it was primarily derived from algae in Tai Lake. Based on the fluorescent characteristics, it was determined that there were seven components, which could be classified as humus, fulvic acid and protein-like substances, such as tryptophan-like and tyrosine-like substances. The fluorescence peak of T₂ and B₂ disappeared during incubation, while other protein-like substances and some more labile components of fulvic acids were released into overlying water. Rates of degradation fulvic acids were greatest. Fluorescence intensity of peak A and C represents fulvic acids decreased by 70.3% and 41.0%, respectively. Humic acids were also a primary constituent of DOM released from aquatic plants. These humic substances could be transformed to fulvic acids during incubation. Five types of fluorescence peaks were detected in DOM from sediments. These included fulvic acids with fluorescence peaks (C and A) and protein-like fluorescence peaks (B₁、B₂、T₂). Peak T₂ disappeared during incubation and peaks B₁ and B₂ decreased by 86.5% and 82.5%, respectively, while the intensity of peaks C and A increased by 25.1% and 1.5%,respectively. Large proportions of protein-like substances were released to the overlying water during incubation of sediment, while some protein-like substances were likely transformed to more stable substances, such as fulvic acids. Therefore, exogenous input and endogenous loading (algae and aquatic macrophyte debris decomposition and sediments release) have important influence on the structure of DOM in water and the process of eutrophication in lakes.

• Key words：three-dimensional excitation-emission matrix fluorescence spectra  dissolved organic matter  eutrophication  algae  sediment

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