利用荧光光谱法研究高原湖泊中溶解有机质组成和腐殖化的深度依赖性变化。
Depth-dependent variations of dissolved organic matter composition and humification in a plateau lake using fluorescence spectroscopy.
机构信息
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 10012, China; College of Water Sciences, Beijing Normal University, Beijing, 100875, China.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 10012, China.
出版信息
Chemosphere. 2019 Jun;225:507-516. doi: 10.1016/j.chemosphere.2019.03.089. Epub 2019 Mar 16.
In aquatic systems, dissolved organic matter (DOM) plays an important role in regulating the reactivity and transport of environmental pollutants. Fluorescence excitation-emission matrix (EEM) analysis combined with fluorescence regional integration (FRI) and parallel factorial analysis (PARAFAC) were applied to investigate the composition, humification degree and depth-dependent variation of DOM in Lake Baihua, China. The results showed that humic-like materials with more than 60% of percentage fluorescence response (P) were dominant in DOM. The molecular complexity and structural condensation of PARAFAC components showed the order of C1 (humic-like components) > C3 (protein-like components) > C4 (fulvic-like components) > C2 (fulvic-like components). The lower maximum fluorescence intensities (F) of components in surface layers were attributed to photo-oxidation of DOM by radiation. With depths less than 16 m, the F increases and decreases were attributed to accumulation of recalcitrant humic substances and microbial/abiotic degradation of particulate DOM, respectively. A combination of biological and humification indices could be used as indicators for distinguishing different degrees of humification and sources of DOM. DOM from Lake Baihua mainly originated from an aquatic bacterial source that consisted of an important/intermediate autochthonous component with a weak humic character. The fluorescence indices of P/P, P/P, C2, C1/C2 and C2/(C3+C4) were more suitable to determine the humification degree. Stronger humic characters and higher humification degree for DOM were present at depths of 10-13 m. The fluorescence spectroscopy combined with fluorescence indices is convenient to investigate depth-dependent DOM characteristics and to assess water quality or pollution risk in lake systems.
在水生系统中，溶解有机物质（DOM）在调节环境污染物的反应性和迁移性方面起着重要作用。荧光激发-发射矩阵（EEM）分析结合荧光区域积分（FRI）和并行因子分析（PARAFAC）被应用于研究中国百花湖 DOM 的组成、腐殖化程度和深度依赖性变化。结果表明，腐殖质样物质占 DOM 荧光响应（P）的 60%以上，占主导地位。PARAFAC 成分的分子复杂性和结构缩合程度表现为 C1（腐殖质样成分）＞C3（蛋白质样成分）＞C4（富里酸样成分）＞C2（富里酸样成分）。表层成分的最大荧光强度（F）较低归因于 DOM 受辐射的光氧化作用。在深度小于 16 m 时，F 的增加和减少分别归因于难降解腐殖质的积累和颗粒 DOM 的微生物/非生物降解。生物和腐殖化指数的组合可作为区分不同腐殖化程度和 DOM 来源的指标。百花湖的 DOM 主要来源于水生细菌源，其中包含一个具有弱腐殖质特征的重要/中间自生成分。P/P、P/P、C2、C1/C2 和 C2/（C3+C4）的荧光指数更适合确定腐殖化程度。在 10-13 m 的深度，DOM 的腐殖质特征更强，腐殖化程度更高。荧光光谱结合荧光指数可以方便地研究深度依赖性 DOM 特征，并评估湖泊系统中的水质或污染风险。
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