长江河口不同分子量溶解有机质的三维荧光光谱特征

Spectroscopic Characteristics of Different Molecular Weight Dissolved Organic Matter in Water from Yangtze River Estuary

应用切向流超滤和三维荧光光谱技术研究长江河口丰水期和枯水期水体中不同分子量溶解有机质的荧光性质,探讨其来源与影响因素。结果表明:长江河口水体存在四种荧光峰,分别是陆源类腐殖酸荧光峰A和海洋来源类腐殖酸荧光峰C、酪氨酸和类蛋白荧光峰B及芳香蛋白荧光峰D。荧光物质主要存在于真溶解有机质(<1kDa)中,其次是低、中分子量胶体有机质(1～500kDa)。溶解有机质中蛋白质来源以污染排放的人为源为主,其次是生物活动的内源;在丰水期腐殖酸来源是陆源和内源,在枯水期主要为陆源。真溶解有机质中腐殖酸多来源于生物分解的内源,胶体有机质以陆源为主,可能同时受再悬浮作用影响。荧光峰强与各环境参数均有一定相关性,说明在环境参数对溶解有机质中的荧光物质产生的影响较为复杂多样。

Cross flow ultrafiltration systems and three dimensional fluorescence spectrum were used to investigate the fluorescence characterization of different molecular weight dissolved organic matter in water of wet season and dry season from Yangtze River estuary,in order to find out the sources and influencing factors.The results showed that four types of dissolved organic carbon（DOM） fluorescence peaks were observed in the water： humic-like fluorescence peak A and C,and protein-like fluorescence peak B and D.Fluorescent substances mainly existed in the truly dissolved organic matter（UOM,1 kDa）,secondly in low and medium molecular weight of colloidal organic matter（1~500 kDa）.Protein of DOM in water mainly originated from anthropogenic sources,then from autochthonous sources.Compared to protein,humic acid of DOM in wet season was both terrigenous and autochthonous sources,while in dry season mainly from terrestrial organic matter.In addition,humic acid in UOM was mainly derived from biological decomposition,however,in colloidal organic matter（COM） came from terrestrial organic matter and was affected by resuspension effects.There was linear correlation between fluorescence intensity and environmental parameters.It was revealed that the complex environmental conditions would influence the fluorescent substance of DOM in water from Yangtze River estuary.