Jiangsu Province is home to the largest area of coastal tidal flat wetlands in China. Impacted by climate change, human activities and other factors, the physicochemical properties and ecological functions of coastal sediments at specific sites have undergone significant changes. Grain size is a key indicator reflecting the physicochemical properties of sediments. However, our current understanding of the grain size distribution characteristics of coastal sediments in Jiangsu and their environmental impacts remains relatively limited. In this study, coastal sediment samples from Jiangsu were systematically collected. The proportion of different components was analyzed, and grain size parameters including mean grain size, kurtosis and sorting coefficient were calculated. Our results showed that the coastal sediments in Jiangsu were dominated by silt, accounting for an average of as high as 85.5%; in comparison, the contents of clay and sand were relatively low, with average proportions of 12.2% and 2.3%, respectively. Among the three coastal cities in Jiangsu, Yancheng exhibited the highest silt content in sediments, but the lowest proportions of sand and clay. Grain size data analysis of the monitoring sections indicates that all three coastal cities in Jiangsu are facing varying degrees of marine erosion. Among them, Lianyungang exhibits a greater extent of marine erosion, whereas specific sites in Yancheng and Nantong are more severely impacted by this process. Analysis of the relationship between grain size and element migration indicated that Nantong, with the highest clay content, has stronger carbon sequestration and pollutant interception capabilities. The results obtained through this large-scale systematic analysis of the grain size of coastal sediments in Jiangsu provide important insights into marine erosion dynamics and support for tidal flat conservation efforts in Jiangsu Province.
Fan et al. (Wed,) studied this question.