Spatial distribution of soil organic carbon across diverse vegetation types in a tidal wetland

Tidal wetlands are significant contributors to global "blue carbon" resources. The water and salt gradients in tidal wetlands shape vegetation distribution and store significant amounts of soil organic carbon (SOC). We selected four distinct regions within the intertidal zone comprising three distinct vegetation types: low-tide saltmarsh Suaeda salsa (LS), high-tide saltmarsh Suaeda salsa (HS), mid-high-tide Phragmites australis (P), and high-tide Tamarix chinensis (T). Through field sampling and indoor analysis, we found significant differences in SOC levels across various vegetation types along the land-sea gradient. Among these, LS exhibited the highest SOC levels, while P had the lowest. Additionally, there were vertical variations of SOC within a 1-m range among different vegetation types. Mantel analysis and SEM demonstrated that SWC influences SOC content by manipulating vegetation types, thereby regulating total soil carbon. Overall, our findings provide valuable insights for further investigating the effects of vegetation succession on soil carbon pool evolution.