Aquatic Bacterial Community Diversity And Molecular Ecological Networks In Typical Reservoirs Of Southern Subtropical China

The number of bacteria in the reservoir ecosystem is large,the diversity composition is rich and the active function accumulated is rich.Bacteria play an irreplaceable role in nutrient circulation,material transformation and energy flow transfer in the reservoir.Reservoir eutrophication will change the composition and structure of the ecosystem,thus affecting the characteristics of bacterial communities.In this study,five typical reservoirs of southern subtropical China were selected as research objects.16 s high-throughput sequencing technique and multivariate statistical analysis were used to explore the community composition and structure of free-living and particle-associated bacteria,alpha diversity and beta diversity,molecular ecological network and the correlation between community and environment in wet and dry season.This study is important for maintaining the functional stability of reservoir ecosystems in southern subtropical China,maintaining the health of drinking water sources and monitoring the increasing eutrophication of water.In view of the above problems,the research results are as follows:1.The dominant groups of bacterial communities in five typical reservoirs in the south subtropics China are Actinobacteria,Alphaproteobacteria,Bacteroidetes,Chloroflexi,Cyanobacteria,Deltaproteobacteria,Firmicutes,Gammaproteobacteria,Planctomycetes and Verrucomicrobia.2.The key environmental factors driving the community structure of free-living bacteria and particle-attached bacteria in five typical reservoirs in the southern subtropical China are temperature and total nitrogen concentration.3.The coexistence relationship between "species" and "species" of bacterial communities in south subtropical reservoirs is more inclined to the cooperation with positive correlation.Compared with the wet season,the bacterial community composition in the dry water season was more strongly affected by environmental selection,and the mutual exclusion between "species" and"species" of the bacterial community was weakened.4.There were differences in the response of free-living bacteria and particle-attached bacteria to eutrophication.Compared with bacteria attached to particles,the composition of free-living bacterial community is more sensitive to eutrophication.5.The dominant groups of free-living bacteria and particle-associated bacteria in the five reservoirs are the same,but the relative abundance of different groups is different in each reservoir.There is a significant difference in bacterial community structure between wet season and dry season.The composition of bacterial community in reservoirs with similar nutritional status is more similar,and the Dajingshan Reservoir is significantly different from other reservoirs.