20世纪50年代中期以来崇明岛东部盐沼发育对长江入海泥沙的响应

Response of evolution of the salt marsh to the sediment discharge from Yangtze River was studied, based on the analyses of grain sizes, contents of particulate organic carbon (POC) and total nitrogen (TN), stable carbon isotope (δ¹³C) and C/N ratios for six cores in the eastern part of Chongming Island salt marsh after mid-1950s, as well as the change characteristics of the sediment discharge from Yangtze River. Results indicated that the change of the grain size for the eastern part of Chongming Island salt marsh after mid-1950s was controlled by the sediment discharge from the Yangtze River. Correlations between contents of organic matter (POC and TN) and contents of grains in different size fractions, and between δ ¹³C and C/N ratios are different for six cores. In the 1960s, the sediment discharge from the Yangtze River was the most, and the sediments in different reaches of the river mixed with each other. This led to both poor correlations between the contents of organic matter (POC and TN) and contents of grains in different size fractions, and between δ¹³C and C/N ratios, respectively. There has been a decline of the correlations between δ¹³C and C/N ratios for the heavy reclamation since the 1990s. This indicated that evolution of the salt marsh in the eastern part of Chongming Island was controlled by the sediment discharge from the Yangtze River from the 1950s to the 1980s. Since the 1990s, evolution of the salt marsh in the eastern part of Chongming Island has been not only controlled by the sediment discharge from the river, but also influenced by human activities such as reclamation.