College of Environment, Hohai University, Nanjing, 210098, China.
Environ Sci Pollut Res Int. 2014 Mar;21(5):3460-73. doi: 10.1007/s11356-013-2287-4. Epub 2013 Nov 19.
The Yangtze Estuary is heavily influenced by coast-continent geochemical processes and anthropogenic activity; thus, the source and distribution of chromophoric dissolved organic matter (CDOM) in the estuary are strongly impacted by these processes. Here, a series of samples were collected from across the Yangtze Estuary to investigate the source and spatial dynamics of CDOM and its components throughout the system. Three indices (a(355), spectral slope, and fluorescence) were then calculated and interpreted. The results indicated that the distribution of CDOM was dominated by allochthonous input, conservative mixing, and phase transfer. The contribution of biogenic CDOM to total CDOM increased with salinity, and three individual CDOM components were identified upon fluorescence excitation emission matrix spectroscopy and parallel factor analysis of the water samples: C1, corresponding to humic substance-like CDOM, C2, corresponding to tryptophan-like CDOM, and C3, corresponding to tyrosine-like CDOM. C1 primarily originated from a terrestrial source, C2 had widespread origins, none of which played a dominant role, and C3 mainly originated from allochthonous input in the medium salinity area. Unexpectedly, no marine humic-like component was found in the surface water of the Yangtze Estuary, possibly because turbidity decreased the depth of sunlight penetration, limiting production of this component.
长江口受海岸带地球化学过程和人为活动的强烈影响；因此，河口的生源色溶解有机物（CDOM）的来源和分布强烈受这些过程的影响。在这里，采集了一系列来自长江口的样本，以研究整个系统中 CDOM 及其组分的来源和空间动态。然后计算并解释了三个指数（a(355)、光谱斜率和荧光）。结果表明，CDOM 的分布主要受异源输入、保守混合和相转移的影响。生物成因 CDOM 对总 CDOM 的贡献随盐度增加而增加，在对水样进行荧光激发发射矩阵光谱分析和平行因子分析后，确定了三个单独的 CDOM 组分：C1，对应于腐殖质样 CDOM；C2，对应于色氨酸样 CDOM；C3，对应于酪氨酸样 CDOM。C1 主要来源于陆源，C2 具有广泛的来源，没有一种起主导作用，C3 主要来源于中盐度区的异源输入。出乎意料的是，在长江口水体的表层水中未发现海洋腐殖质样成分，这可能是因为浊度降低了阳光穿透的深度，限制了该成分的产生。
