Changes and Influencing Factors of Carbon Content in Surface Sediments of Different Sedimentary Environments Along the Jiangsu Coast, China

Coastal areas are essential for global ‘blue carbon’ burial, significantly impacting the global carbon cycle. To better understand the carbon burial capacity, impact factors, and response mechanisms of surface sediments in different coastline regions, this study investigated the surface sediments of the Spartina alterniflora vegetation, transition, and bare flat areas along Jiangsu coast in China. The results indicated significant changes in organic carbon (OC), inorganic carbon (IC), and various physicochemical property indicators between the three coastal environments. There were also significant differences in the important impact factors of OC and IC in each region. In areas of vegetation, OC and IC influenced each other, while nitrogen (N), clay, and sand were common impact factors. The pH only had a significant impact on OC. In the bare flat area, the important impact factors of OC and IC were identical: OC/IC, clay, salinity (SAL), and sand. However, the important impact factors of OC and IC in the transition area have undergone significant changes. The important impact factors of OC were N, total phosphorus (TP), total sulfur (TS), SAL, and sand. The partial least squares regression analysis results of IC were poor, and there were no important impact factors. This study refined the spatial distribution patterns and response mechanisms to the important impact factors of carbon in different coastal subregions, providing a basis for accurately evaluating the role of coastal wetlands in mitigating global climate change.