Study On The Characteristics And Indicative Effects Of Bacterial Community On Water And Sediment In Polluted Ponds

Aquatic ecological environment is the basis for the existence of human society,and plays an irreplaceable role in regulating the global climate and maintaining the stability of the natural environment.Water pollution caused by human activity has become one of the most important environmental problems in world today.Water pollution greatly impact industry,agriculture,fishery,and human health.Microbial communities were considered as biological indicators in freshwater ecosystems due to their large number,wide distribution,rich diversity,and extreme sensitivity to physicochemical properties.Microbial indicators screened by different pollution levels could track the pollution levels of aquatic ecosystems and provide insights into the assessment and prediction of water quality deterioration,which have important application value and ecological significance for the detection of pollution in aquatic ecological.In this study,we selected several polluted ponds in northern China as the research object.These ponds were divided into three pollution gradients based on the calculation of comprehensive pollution indexes.The microbial communities were investigated by using the 16S rRNA gene high-throughput sequencing technology both in water and sediment from the polluted ponds.The main results are as follows:?1?According to the“Environmental Quality Standards for Surface Water”?Chinese 2002?GB3838-2002??,the concentration of NH₃-N,COD,TN,and TP in water samples seriously exceeded the criteria V.With the increasing of pollution levels,exclusion of p H,most of the environment variables gradually increased.Compared with grade A of the“Chinese Control Standards of Pollutants in sludge for Agricultural use?GB4284-2018?”,all heavy metal variables were lower than the national standards.?2?Bacterial community diversity,structure and composition in water samples were significantly different among different levels polluted ponds.The relative importance of stochastic processes in the governing community structure decreased substantially with the increase of pollutant levels.The LEfSe analysis showed that Actinomycetales and Planctomycetaceae were the indicators microorganisms for mild pollution ponds;Anaerolineales,Acidimicrobiales,and Acidimicrobiaceae were the indicators microorganisms for severe pollution ponds.?3?In sediment samples,the diversity,structure and composition of bacterial community were significantly altered among different levels polluted ponds.Stochastic ratios of bacterial community were decreased gradually with the increase of pollution levels.The LEfSe analysis revealed that Clostridiales was the indicator microorganism for mild pollution;Erysipelotrichales,Lactobacillales,Synergistales,Bacteroidales,Flavobacteriales,Erysipelotrichaceae,Synergistaceae,Porphyromonadaceae and Cryomorphaceae were the indicator microorganisms for severe pollution.The paper has 20 figures,20 tables,and 115 references.