Department of Environmental Science and Engineering, College of Resources and Environment, Southwest University, Chongqing 400716, China; Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå SE-90183, Sweden.
Department of Environmental Science and Engineering, College of Resources and Environment, Southwest University, Chongqing 400716, China.
Sci Total Environ. 2018 Sep 15;636:249-259. doi: 10.1016/j.scitotenv.2018.04.262. Epub 2018 Apr 26.
Dissolved organic matter (DOM) is a crucial driver of various biogeochemical processes in aquatic systems. Thus, many lakes and streams have been investigated in the past several decades. However, fewer studies have sought to understand the changes in DOM characteristics in the waters of the Three Gorges Reservoir (TGR) areas, which are the largest artificial reservoir areas in the world. Thus, a field investigation of dissolved organic carbon (DOC) concentrations and of chromophoric dissolved organic matter (CDOM) properties was conducted from 2013 to 2015 to track the spatial-temporal variability of DOM properties in the TGR areas. The results showed that the alternations of wet and dry periods due to hydrological management have a substantial effect on the quantity and quality of aquatic DOM in TGR areas. Increases in DOC concentrations in the wet period show an apparent "dilution effect" that decreases CDOM compounds with relatively lower aromaticity (i.e., SUVA) and molecular weight (i.e., S). In contrast to the obvious temporal variations of DOM, significant spatial variability was not observed in this study. Additionally, DOM showed more terrigenous characteristics in the dry period but weak terrigenous characteristics in the wet period. Furthermore, the positive correlation between SUVA and CDOM suggests that the aromatic component controls the CDOM dynamics in TGR areas. The first attempt to investigate the DOM dynamics in TGR areas since the Three Gorges Dam was conducted in 2012, and the unique patterns of spatial-temporal variations in DOM that are highlighted in this study might provide a new insight for understanding the role of DOM in the fates of contaminants and may help in the further management of flow loads and water quality in the TGR area.
溶解有机质（DOM）是水生系统中各种生物地球化学过程的关键驱动因素。因此，过去几十年里许多湖泊和溪流都得到了研究。然而，对于世界上最大的人工水库三峡库区（TGR）水体中 DOM 特征的变化，研究较少。因此，我们于 2013 年至 2015 年进行了一项实地调查，以追踪 TGR 地区 DOM 特性的时空变化，调查内容包括溶解有机碳（DOC）浓度和发色溶解有机质（CDOM）特性。结果表明，由于水文管理导致的干湿交替对 TGR 地区水生 DOM 的数量和质量有重大影响。在湿期，DOC 浓度的增加表现出明显的“稀释效应”，降低了具有相对较低芳香度（即 SUVA）和分子量（即 S）的 CDOM 化合物。与 DOM 的明显时间变化相反，本研究未观察到明显的空间变化。此外，DOM 在枯水期表现出更多的陆源特征，而在丰水期表现出较弱的陆源特征。此外，SUVA 与 CDOM 之间的正相关表明，芳香族成分控制了 TGR 地区 CDOM 的动态变化。这是自 2012 年三峡大坝建成以来首次对 TGR 地区 DOM 动态进行的研究，本研究强调的 DOM 时空变化的独特模式可能为理解 DOM 在污染物命运中的作用提供新的视角，并有助于进一步管理 TGR 地区的水流负荷和水质。
