Abstract:

The Yangtze River estuary is one of the largest estuaries in the world. Baimaosha, Biandansha, Zhongyangsha, Jiuduansha and Chongming island have been formed by rapid sedimentation in different stages of the estuary development. As sedimentation has progressed, there are associated changes in organic carbon content in the surface sediments. Few previous research has been completed on organic carbon concentrations in surface sediments of the estuary islands in relation to the growth of the island wetlands. This research investigated the concentrations of organic carbon within surface sediments of the wetland island progressing to land. Results showed that the carbon content in the surface sediments increased when the island wetlands progressed to land. The most recent formed wetland island had a low organic carbon content, such as Baimaosha, 1057%; with the development of the island wetlands to land, the organic carbon content increased gradually, such as the sediments in east beach of Chongming island, had a concentration of 3176%. In addition, the organic carbon content increased gradually with the increase in altitude. The highest concentrations were in the reed zone, 3004%; the lowest were in bare beach region, 1436%; the concentrations of 〖WTBX〗Scirpus mariqueter〖WTBZ〗 zone were between them, 1812%. However, the organic carbon content became uneven when the island wetlands was developing to land, which also explained the changing law of the organic carbon content in the surface layer of the island wetlands development. The study indicates that the island wetlands in estuary play an important role in storing organic carbon when processing to land