Contemporary sedimentation rates on salt marshes at Wanggang, Jiangsu, China

The total area of coastal wetlands exceeds 5000 km² in Jiangsu Province, China, but it has been decreasing rapidly as a result of intense reclamation activities. Two types of plants, Spartina angelica and Spartina alterniflora, were introduced successively into the Jiangsu coast, in order to protect the coastline from erosion and to increase the accumulation rate. ²¹⁰Pb and ¹³⁷Cs analyses were carried out for sediment samples from the salt marshes of Wangang, to derive the sedimentation rate, on the basis of an evaluation of the background values and factors affecting the enrichment of ²¹⁰Pb. Analysis of a typical sediment column of the tidal flat shows that the absorption of ²¹⁰Pb in the silt-dominated sediment is weak. Influences of storm events, bioturbation, material sources and analytical error also have an effect. As a result, some abnormal data points are present. These data were removed before the calculation of the sedimentation rate. The sedimentation rate was 3.3 cm a^-1 on average. Based upon analysis of the ¹³⁷Cs dating, the rate since 1963 was 3.1 cm a^-1 on average, similar to the data by ²¹⁰Pb dating and from previous studies.