[Spectroscopic characteristics of different molecular weight dissolved organic matter in water from Yangtze River estuary].

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).