摘要：Lake microorganisms are an important part of the aquatic ecosystem, which can directly or indi-rectly affect the material and energy cycles of the aquatic ecosystem. Danjiangkou Reservoir is the water source area of the Middle Route of the South-to-North Water Transfer Project. Its water quality directly affects the drinking water quality of more than 100 million people along the way. Therefore, long-term monitoring of the microbial community composition of Danjiangkou Reservoir is of great significance. However, relatively little work has been carried out at present. In order to explore the diversity of bacterial communities in areas with different nutritional levels, high-throughput se-quencing was used to analyze the diversity of bacte-rial communities, to study the composition and distribution characteristics of bacterial communi-ties, with a view to discovering the ecological com-position of the microbial community in Danjiang-kou Reservoir, its influencing factors, and discuss-ing the composition of floating bacteria, the rela-tionship between its abundance and physical and chemical factors of water quality, in order to estab-lish a biological indicator method suitable for Dan-jiangkou Reservoir water quality, sequence the 16SrDNA gene of bacteria,and provide a reference for Danjiangkou Reservoir water environmental protection. The results found: The water quality of Danjiangkou Reservoir is generally good.However, due to pollution from agricultural non-point sources and domestic sewage in villages and towns, total nitrogen (TN) has significantly exceeded the stand-ard. There are differences in the composition of the dominant bacterial community at different sampling points. The total sequence of Gammaproteobacte-ria, Holophagae, Alphaproteobacteria,Oxyphoto-bacteria, Bacteroidia, Acidimicrobiia, Actinobacte-ria accounts for about 90%of the total sequence, and these bacteria are the dominant group.At HJW, Gammaproteobacteria is as high as 39,63%. The dilution curve reflects that the OTUs generated by clustering at each sampling point are BSZ>TBDq>HJW>BX. This experiment has a comprehensive and accurate understanding of the composition of the planktonic bacterial community in the Danjiangkou reservoir area.
