Analysis Of Bacterial Community Structure In Littoral Wetland Of Wuliangsuhai Lake Based On PCR-DGGF

As an functional composition of the wetland ecosystem, the soil microbes play a key role in biogeochemical cycles. The agricultural waste water is probably the main source of Wuliangsuhai water pollution, resulted in the increased eutrophication, and great shift in structure and functions of wetland ecosystem.The thesis puts forward hypothesis as follows:the bacterial community of aquatic sediments and soils are likely to respond to wetlands degradation, caused by lake eutrophication and the characters of community structure of the terrestrial area may be significantly impacted. The aim of this study was to analyze the bacterial community structure and diversity and study the effect of eutrophic substrate on the bacterial composition.We focuses on 4 landward sites in littoral wetland of Wuliangsuhai Lake, using the denaturing gradient gel electrophoresis (DGGE) with PCR-amplified 16S rRNA fragments to determine bacterial diversity. The ordination technique of canonical correspondence analysis (CCA) was used to evaluate its effects on bacterial community composition.The result shows that the bacterial community structure of landward sites in Wuliangsuhai wetland has significantly difference, meanwhile the microbial diversity decreased gradually from eutrophic lake sediment to desert soil. There are 3 phyla in 4 samples, including Proteobacteria (78.6%), Acidobacteria (7.1%), and Bacteroidetes (14.3%). Proteobacteria (52.6%) were the dominant species, in which the Epsilon proteobacteria were predominant subgroup.We have discovered a variety of bacteria similarity with functional bacteria, plays a key role in the cycle of carbon, nitrogen, and sulfur or in the degradation of pollutants, responsed to lake eutrophication. We analyzed the impact of physical and chemical factors on bacterial community structure and diversity.The results suggested that eutrophic relative factors had a strong effect on the bacterial community structure. NH4+-N, total nitrogen, organic carbon, total soluble salt, Cl-and K+ have most significant influenced on the distribution of bands related species, especially dominant population. 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.