Study On Microbial Community Characteristics Of Water And Sediments In Three Lakes Of Hubei Province

As important members of the freshwater ecosystem,microbes play an important role in the material cycle and energy flow.Microorganisms are susceptible to external physical and chemical factors,especially those microorganisms in the surface water of lakes,which are susceptible to light,temperature,dissolved oxygen and nutrients.The relationship between microbial community structure and environmental factors will change as the region changes.In this study,high-throughput sequencing technology was used to sequence 16S rRNA genes of microbes in the water and sediment from three lakes in Hubei Province,aiming to clarify the microbial community information of these three lakes which were eutrophicated due to large numbers of terrestrial pollutants and intensive human activities.At the same time,the relationship between microbial community structure and environmental factors was illustrated.The main results were as follows:?1?Among the three lakes,the abundance and diversity in the sediments were significantly higher than that in the water,and the microbial diversity in the littoral areas was higher.In addition,the abundance of microbial community in the water and sediments of the Daye Lake during dry season were higher than that during the wet season,but the diversity was lower than that during the wet season.?2?A total of 50 bacterial phylum were detected at four sites in the Daye Lake.The microbial community structure was significantly different between the water samples in the dry season and the wet season.In the main bacteria,the relative proportions of Proteobacteria and Bacteroides in the dry season were higher than that in the wet season.The relative proportions of Actinobacteria and Cyanobacteria in the dry season were lower than that in the wet season.However,the microbial community structure of sediment samples was not significantly different.The main bacteria were Proteobacteria,Chloroflexi,Acidobacteria,Nitrospirae,Actinobacteria,and so on.There were significant differences in microbial community structure between sediment and water samples.The relative proportions of the dominant communities of Chloroflexi,Acidobacteria and Nitrobacteria in the sediments were significantly higher than that in the water.The relative proportions of the dominant communities of Proteobacteria,Actinomycetes,Cyanobacteria and Bacteroidetes in sediments were significantly lower than those in the water.?3?A total of 52 bacterial phylum were detected at ten sites in the Liangzi Lake.There were significant differences in microbial community structure between sediment and water samples.The relative proportions of the dominant communities of Actinobacteria,Bacteroidetes,Cyanobacteria,and Armatimonadetes in the water were significantly higher than that in sediments,while the relative proportions of the dominant communities like Proteobacteria,Chloroflexi,Acidobacteria,Nitrobacteria,and Gemmatimonadetes were significantly lower than those in sediments.There were significant differences in microbial community structure among water samples,but not among sediment samples.?4?A total of 48 bacterial phylum were detected at five sites in the Houguan Lake.The relative proportions of the dominant communities of Actinobacteria,Cyanobacteria,Bacteroidetes,Verrucomicrobia,Armatimonadetes,and Gemmatimonadetes in the water were significantly higher than that in the sediments,while the relative proportions of dominant communities like Proteobacteria,Chloroflexi,Nitrospira,and Acidobacteria,were significantly lower than those in sediments.The microbial community structure of the Houguan Lake was similar to that of the Liangzi Lake.There were significant differences in microbial community structure among water samples,but not among sediment samples.?5?In all the three lakes,the microbial community structure was more susceptible to environmental factors.The dominant microbial communities in water samples were mostly related to the contents of nitrogen?N?and carbon?C?,while the dominant microbial communities in sediment samples were mostly related to the contents of nitrogen and phosphorus?P?.Among the environmental factors tested,total nitrogen?TN?,total phosphorus?TP?and salinity?SAL?were the main factors that influenced the microbial community in the Daye Lake.The total phosphorus,pH,and SAL were the main factors that influenced the microbial community in the Liangzi Lake.The nitrate nitrogen?NO₃^--N?was the most important factor that affected the microbial community in the Houguan Lake,and nitrite nitrogen?NO₂^--N?,TN and total organic carbon?TOC?also had important effects on it.