Effect of Dissolved Oxygen on Microorganisms Decomposing Litter from Poyang Lake

There are a lot of litter in Poyang Lake. The decomposition of these litter will have a significant impact on the nutrient cycle of Poyang Lake. The impoundment of the Three Gorges Dam (TGD) changed the water level of Poyang Lake. In the process of water level fluctuation, the dissolved oxygen (DO) concentration of Poyang Lake changes. This will affect the microbial community structure in the water. Microorganisms are the main force to decompose litter. This study tested the decomposition rate and microbial community structure of dominant plants of Poyang Lake under anaerobic environment (0 mg/L O2) and high DO concentration environment (8 mg/L O2) in the laboratory. The results show the decomposition rate of high DO group is significantly higher than anaerobic group’s. In addition, high DO group has more Bacilli, Eurotiomycetes and Wallemiomycetes, which is the main reason for accelerating the decomposition rate of litter. This study provides a reference for a reference for the management of Poyang Lake and the TGD impoundment.