Halophyte Vegetation Influences Soil Microbial Community of Coastal Salt Marsh

Coastal wetlands are the most productive ecosystems worldwide and can provide important ecosystem services, yet the characteristics of microbial community within these systems remain poorly understood. Microbial community of salt marsh vegetation and the associated soil physio-chemical properties were investigated in this study. Three typical Suaeda australis, Phragmites australis, Spartina alterniflora wetlands, and non-vegetated bare mudflats in the Zhoushan Islands were studied to advance the understanding of the characteristics of soil bacterial communities in coastal wetlands. Results showed that the bare mudflats exhibited high pH value and soil moisture content compared with the vegetated samples. In different vegetation types, the organic matter content, total nitrogen, and total potassium content decreased in the order: S. alterniflora wetland > P. australis wetland > S. australis wetland, and there was no obvious difference in total phosphorous content. The halophytes could decrease soil salinity compared with bare mudflats. Proteobacteria, Nitrospinae, Bacteroidetes, Acidobacteria, and Nitrospirae were the predominant level across all samples. Functional prediction showed that SPA-covered soil might play vital roles in sulphur cycling, while SUA and PHR covered soils were involved in nitrogen cycling. This study could provide the first insight into the microbial community of this study area and contribute to a better understanding of vegetation microbiota and bioremediation in coastal wetland ecosystem.