College of Environment and Resources, Inner Mongolia University
Bacteria are important drivers for nearly all biogeochemical cycles in wetland ecosystems. Soils and sediments from Wuliangsuhai wetland, a previously uncharacterized natural wetland located in western Inner Mongolia, China, were surveyed to characterize the structure and diversity of its microbial communities using barcoded pyrosequencing based on the 16S rRNA gene. Samples were collected along a transect that spanned vegetated uplands, exposed lakebed sediments, and water-logged locations. The overall microbial communities were unexpectedly diverse. Six phyla of Proteobacteria,Bacteroidetes, Chloroflexi, Planctomycetes, Firmicutes and Deinococcus–Thermus exist in all samples. Proteobacteria was the most abundant phylum. The relative abundance of Proteobacteria in lake sediments was higher than other soil samples, showing that Proteobacteria maybe have important roles in lake sediment atthe phylum level. At the genus level, the dominant genera were Thiobacillus, Sulfurimonas, Sinobacteraceae, Anaerolineaceae and Caldilineaceae. Sulfurimonas was the dominant genus in lake sediments, and higher than that in other samples. Further, we used multivariate statistics to identify the relationships shared between sequence diversity and heterogeneity in the soil environment.The relative abundances of bacterial groups at different taxonomic levels correlated with total phosphorus (TP), Total nitrogen (TN) and ammonium nitrogen centrations, but little or no relationships to organic carbon (OC). Eutrophic relative factors had a strong impact on the bacterial community structure,ammonium nitrogen was the most important factor explaining the differences in bacterial communities across samples. Hence, soil factors affect the bacterial community structure, which has profound consequences on ecosystem function.
keywords:Wuliangsuhai,eutrophic Lake wetland,bacteria diversity,pyrosequencing