Distribution characteristics and influences of soil organic carbon in the coastal wetland of Lianyungang

Objective Coastal wetlands, a unique type of wetland with complex hydrologic and biogeochemical cycles, have ignificant carbon sequestration potential. Research on soil organic carbon (SOC) is critical for understanding carbon cycle, climatic regulation, and ecosystem health. Methods This study focused on four typical vegetation types grown in the coastal wetlands of Lianyungang, namely, Mudflats, Seepweed, Spartina alterniflora and Reeds. We analyzed the distribution characteristics of soil organic carbon content across different plant communities, and utilized statistical methods such as pearson correlation analysis, redundancy analysis (RDA), and structural equation modeling (SEM) to explore the regulatory effects of plant community characteristics and soil physicochemical properties on soil organic carbon. Particular attention was given to the relationships between environmental factors of coastal wetlands and soil organic carbon content. Results Horizontally, the soil organic carbon content of the different plant communities decreased in the following order: Reeds ((7.79±4.72) g/kg)>Spartina alterniflora ((7.42±3.14) g/kg)>Seepweed ((4.95±3.40) g/kg)>Mudflats ((3.66±1.90) g/kg). Vertically, the soil organic carbon content decreased with increasing depth within 0-50 cm. Additionally, significant correlations were found between SOC content and soil physicochemical properties, as well as plant community characteristics. The results of the redundancy analysis indicate that soil organic carbon content is negatively correlated with BD (bulk density) in different wetland types but is positively correlated with SWC (soil water content), height, diameter, coverage, AGB (above ground biomass) and BGB (below ground biomass). The structural equation model showed that the soil water content was the most important factor affecting soil organic carbon content in coastal wetlands. Conclusion These findings can not only promote a better understanding of coastal wetlands from their ecosystem structure and function but also provide relevant data support for policy making on global climate change.