Characterization of dissolved organic matter under contrasting hydrologic regimes in a subtropical watershed using PARAFAC model
Characterization of dissolved organic matter under contrasting hydrologic regimes in a subtropical watershed using PARAFAC model
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DOI：
10.1007/s10533-011-9617-8
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发表时间：
2012-07-01
期刊：
影响因子：
4
通讯作者：
Yu, Xiangxiang
中科院分区：
文献类型：
--
作者：
Hong, Huasheng;Yang, Liyang;Yu, Xiangxiang
在受亚洲季风、热带风暴和人类活动影响的九龙江流域进行了5次流域尺度调查（风暴后和干旱期），研究了九龙江流域溶解有机质（DOM）的变化特征。溶解有机碳浓度，DOM吸收和荧光（激发-发射矩阵光谱，EEMs）进行了测量。并行因子分析（PARAFAC）的EEMs确定了三个类腐殖酸和两个类蛋白质的荧光成分。干旱时两个污染站DOM浓度最高，而原始水源（N1站）最低。2009年5月暴雨后DOM浓度增加最明显，说明在汛期来临前DOM从陆地向河流的有效冲刷。在2009年5月和6月的风暴后，PARAFAC结果中的蛋白质类组分减少，突出了DOM组成的变化，从而突出了其环境作用。水坝的修建可能增加了DOM在河流中的停留时间，使得风暴期间DOM的流入对河流（与河口相比）的生态地球化学过程有更多的影响。2008年8月的暴雨对前期几次暴雨的DOM冲刷作用不明显。严重甲藻水华发生在极端干旱期间，在较低的流域，增加DOM浓度和蛋白质类馏分在受影响的站点。利用这两种蛋白质组分对水华期间和水华后不同DOM组分进行了区分。这项研究表明了水文制度和人类活动对淡水DOM及其环境作用的重要性，这对其他一些具有相似特征的河流具有影响。
Dissolved organic matter (DOM) was characterized during five basin-scale investigations (either after storms or in droughts) in Jiulong River, China that is affected by the Asian Monsoon, tropical storms and anthropogenic activities. Dissolved organic carbon concentration, DOM absorption and fluorescence (excitation-emission matrix spectra, EEMs) were measured. Parallel factor analysis (PARAFAC) of EEMs identified three humic-like and two protein-like fluorescent components. DOM concentration was highest at two polluted stations in droughts while lowest in pristine headwaters (station N1). DOM concentration increased most evidently after storms in May, 2009, indicating effective flushing of DOM from land to the river close to the onset of flood season. The protein-like fraction in PARAFAC results decreased after storms in May and June, 2009, highlighting changes in DOM composition and thus its environmental role. Dam constructions likely increased the residence time of DOM in river, making the inflow of DOM during storms have more implications for the riverine (in comparison with estuarine) biogeochemical processes. The effect of storm in August, 2008 after intense DOM flushing during several preceding storms, was not evident. A severe dinoflagellate algal bloom occurred during the extreme drought in the lower watershed, which increased DOM concentration and the protein-like fraction at impacted stations. Different DOM compositions during and after algal bloom were discriminated using the two protein-like components. This study demonstrates the importance of hydrologic regimes and anthropogenic activities on freshwater DOM and its environmental role, which has implications for a number of other rivers that share similar characteristics.