Soil bacterial community assemblage and associated physicochemical characteristics along a moisture gradient of the Wuliangsuhai wetland in China

Bacteria are important drivers of biogeochemical cycles and participate in nutrient transformations in wetland ecosystems. We identified 4 sites along a soil moisture gradient of a degraded prairie wetland in Inner Mongolia, China, that could be classified according to dominant vegetation type. Along with various soil physicochemical measurements, the soil bacterial communities were evaluated using 16S rDNA multiplex 454 pyrosequencing. The taxonomic classification revealed significant variation in bacterial community assemblage across the 4 sites. Community diversity was strongly correlated with soil moisture content, with linear relationships in the abundance of certain phyla being observed along the transect in a distance-dependent manner. Furthermore, several bacterial communities were also found to be associated with total nitrogen composition in the soil. Together, these were found to be primary factors influencing bacterial diversity. Additionally, total phosphorous and organic carbon were identified as important limiting resources for the dominant microbial lineages identified.