Study On The Structure Characteristics And Diversity Of Functional Bacteria Communities In Different Nutritional Lakes In Yunnan Plateau

Fuxian Lake and Xingyun Lake,located in the southwest of China,are important plateau freshwater lake resources in China.The two lakes are sensitive to environmental changes,which are of great significance in regulating climate and maintaining sustainable development of ecological environment.Microorganisms play an important role in regulating the circulation of geochemical elements.In this study,the water and sediments of Fuxian Lake and Xingyun Lake were used as the research objects to explore the diversity and gene abundance of element cycle functional genes.Through functional gene amplicon sequencing,the element cycle functional microorganisms of Fuxian Lake and Xingyun Lake were analyzed.The group structure composition,abundance and its correlation with lake environmental factors were studied.The main findings are as follows:1.There are significant differences in environmental factors in the water samples and sediments of Fuxian Lake and Xingyun Lake in Yunnan Plateau.The water body transparency of Fuxian Lake is higher than that of Xingyun Lake.The water temperature,dissolved oxygen,pH and chlorophyll a of Xingyun Lake are higher than those of Fuxian Lake.The chlorophyll a in the waters of Fuxian Lake and Xingyun Lake have seasonal patterns.The oxygen demand(COD)is much higher than that of Fuxian Lake,and the nitrogen and phosphorus contents in the water and sediments of Xingyun Lake are higher than those of Fuxian Lake.Different functional microbial flora is affected differently by environmental factors.In general,the nitrogen cycle microbial flora of the two lakes is greatly affected by total nitrogen,total phosphorus,chemical oxygen demand(COD),dissolved oxygen(DO),sodium,and potassium.The phosphorus cycle microbial flora of the two lakes is affected by total phosphorus and ammonium.The influence of nitrogen,dissolved oxygen(DO),orthophosphate,calcium,magnesium,etc.;the microbial flora of the sulfur cycle in the two lakes is greatly affected by total phosphorus,ammonium nitrogen,dissolved oxygen(DO)calcium,magnesium,and pH.2.The diversity of functional genes in the sediments of Fuxian Lake and Xingyun Lake in Yunnan Plateau is significantly affected by seasonality.In the nitrogen cycle,the diversity of nirS-type denitrifying bacteria and nosZ-type denitrifying bacteria is relatively rich.The diversity of amoA in the sediments of Fuxian Lake and Xingyun Lake is not significantly affected by lake eutrophication,and ammonia oxidizing archaea is less affected by lake eutrophication.The nirS gene,nosZ gene,mcrA gene,phoD gene,and dsrB gene in the sediments of Xingyun Lake of Fuxian Lake were significantly affected by seasonal variation.The abundance of different functional genes varied with the environment.The mcrA and phoD genes of the carbon and phosphorus cycles are high in water samples,while the dsrB gene of the sulfur cycle has a high abundance sediment content,and the functional genes of the nitrogen cycle are different.The functional genes of different element cycles in the water of Fuxian Lake and Xingyun Lake are greatly affected by the eutrophication degree of the lake.The gene abundances of nir S gene,nos Z gene,amo A(AOB)gene,pho D gene and dsr B gene in the water of Xingyun Lake are higher than that in Fuxian Lake.There is a significant positive correlation between the microbial flora of the lake element cycle and the toxin-producing cyanobacteria.Among them,ammonia oxidizing archaea(AOA),ammonia oxidizing bacteria(AOB),and denitrifying bacteria(nir S)in the nitrogen cycle have a greater impact on the toxin-producing cyanobacteria.It is speculated that the activity of the microbial flora with the element cycle function affects the toxin production mechanism of the toxin-producing cyanobacteria.3.The results of the study on the structure and composition of functional microbial communities in the two lakes show that: based on the nirS gene amplicon sequencing,it was found that Fuxian Lake and Xingyun Lake are mainly composed of aerobic denitrification bacteria(Thauera),Pseudomonas(Pseudomonas),etc.The community is dominant,and Thiothrix is a unique microbial community in Fuxian Lake.Amplicon sequencing based on the pho D gene revealed that Fuxian Lake and Xingyun Lake are dominated by Bacillus,Streptomyces,Xanthomonas and other communities.Amplicon sequencing based on the dsr B gene revealed that Fuxian Lake and Xingyun Lake were mainly composed of Desulfotomaculum and Desulfovibrio communities.