Different Water Level Elevation Of Poyang Lake Wetland Soil Microbial Community Structure And Function Change Research

Poyang Lake is the largest freshwater lake in Chinaforming a large wetland with alternation of wet and dry due to the action of the five major river basin and the water level of the Yangtze River. In recent years, climate change, human activity and the impact of the Three Gorges dam operation, resulting in shrinking lake area, wetlands and tidal flats exposed ahead of time, thus wetland ecological balance is sufferring serious damage. Microorganism plays an irreplaceable role in maintaining the ecological balance of the wetland. The knowledge about howthe microbial community structure and function respond to different level elevation is significant in this study, according to the different elevation and the distribution of vegetation’s succession. Six sample plots was set up in the Banghu Lake, which is one of the most representative Shallow-Lakes in the Poyang Lake wetland ecosystem. From the shore to the center of the Bang Hu, these six sample plots referred to as H1, H2, H3, H4, H5, H6. The surface soil were collected from each sample plot, followed by physical and chemical properties, heavy metals and pollution situation analysesThe soil microbial metabolic activity and function were evaluated bysoil enzyme activities and soil microbial activities on the use of different carbon sources The traditional counting microbial culture and highthroughput sequencing(Illumina Miseq) were combined to investigate the soil microbial community structure and abundance. The relationship between soil environmental factors, soil microbial activity and microbial community structure function were analyzed through pearson correlation analysis. The main conclusions are as follows: 1. Soil properties, microbial community structure and functional characteristics are significantly different as the water level elevated. In the H5(Nandi) plot, the AFDM, TOC, TN content were the highest,while the TP and heavy metal content was the lowest. Besides, the microbial biomass, soil enzyme and metabolic capacity of carbon source were the highest; the bacterial and fungal richness were the highest, but with the lowest diversity. 2. The distribution of wetland soil bacteria and fungi community was similar, and the similarity of two successively adjacent plotswas more obvious. The plots without vegetation(H1, H2) clustered together; while the plots with vegetation(H3-H6) formed the other clade. The H3-H6 plots were furtherdivided into two cluster, namely H3, H4 and H5, H6. 3. The microbial carbon utilization increased as the increase of altitude. The profiles of microbes community structure and metabolic function were consistent. 4. The main environmental factors affecting the wetland soil microbial community structure and function were as follows: SM, pH, nutrients(AFDM, TOC, TN, TP) and Mn. 5.The role of bacterial community plays a greater role in the carbon and nitrogen metabolism and other organic matter mineralization process than the fungal community.