(1) 中国科学院烟台海岸带研究所海岸带环境过程与生态修复重点实验室

55 surface sediment samples were collected from Changjiang Estuary and its adjacent sea in the summer 2016. Grain sizes, total organic carbon (TOC), total nitrogen (TN),carbon and nitrogen stable isotopes (delta~(13)C and delta~(15)N) were analyzed to study the spatial distribution, sources and environmental indication of organic matters in surface sediment in the area. Significant correlations were found between terrestrial organic matter input, sediment grain gize, sea current and the spatial distribution of organic matter. In a comparison, higher TOC (>0.5%) and TN (>0.08%) values occurred in the south offshore of Changjiang Estuary and the offshore of Zhejiang province with fine grain size; lower TOC (<0.4%) and TN (<0.05%) values occurred in the northern Changjiang Estuary with sandy silt sediments. The results indicated that finer grain size was able to concentrate organic matter better. Ranges of delta~(13)C (-23.94~-20.49)and TOC/TN (6.45~11.16) indicated a mixture of terrestrial and marine derived organic matter. The relative contribution of the terrestrial-derived organic carbon (f: 13.00~58.45%) and marine-derived organic carbon (TOC_(marine): 0.12~0.55%) were analyzed to indicate that the proportion of marine and terrestrial input follow the spatial distance from coastal to offshore, and the pathway of the Changjiang Diluted Water. Marine organic matters were significantly increased at 123°E eastward. The range of delta~(15)N (3.66~5.38) indicated that the source of nitrogen in the surface sediments was affected by a variety of natural and artificial factors in the sea area. The indication of the nitrogen sources need to be further determined in conjunction with other relevant parameters.