[Bacterial diversity in littoral wetland of Wuliangsuhai Lake]

The aim of this study was to analyze the bacterial diversity of land-water transition zone in littoral wetland of Wuliangsuhai Lake, and to study the effect of eutrophic substrate on the bacterial composition.

The denaturing gradient gel electrophoresis (DGGE) with PCR-amplified 16S rDNA fragments was used to determine bacterial diversity, and the ordination technique of canonical correspondence analysis (CCA) was used to evaluate its effects on bacterial community composition.

DGGE result shows that the microbial quantity decreased gradually from eutrophic lake sediment to desert soil. Diversity index analysis shows that the Shannon-Wiener index (H), Evenness index (E), richness index (S) and Simpson index (Ds) decreased gradually from water to land (eutrophic lake sediment > swamp sediment > saline soil > desert soil). Based on the sequencing results, there are 3 phyla in 4 samples, including Proteobacteria (78.6%), Acidobacteria (7.1%), Bacteroidetes (14.3%), Proteobacteria (52.6%) were dominant species, in which the Epsilon proteobacteria were predominant subgroup. The results of CCA suggest that that NH4+ -N, total nitrogen, organic carbon, total soluble salt, Cl- and K+ have most significant influenced the distribution of bands related species.

The bacterial community structure of transition zone in Wuliangsuhai wetland differed significantly, and eutrophic relative factors had a strong impact on the bacterial community structure. This work presented a certain reference for the preliminary understanding of the bacterial composition and diversity and provided a scientific foundation for the research of spatial heterogeneity in this transition zone.