Study On The Microbial Community Structure Of Jialing River Basin In Different Periods

With the rapid development of China's industry and agriculture,economy,the discharge of industrial and agricultural and domestic wastewater has caused some pollution to the river.As an important part of the aquatic ecosystem,microorganisms play an important role in the material cycle,energy flow,and decomposition of organic matter in river ecosystems.To a certain extent,it can purify water quality and indicate the degree of water pollution.At the same time,the physicochemical properties of the water and seasonal changes will also affect the structure of the microbial community in the water.Based on this,the content of this study is about the physicochemical characteristics near the typical area of the Jialing River basin(farmland,scenic area,hospital,park square,scenic area,residential area)and uses high-throughput sequencing to explore the structural characteristics of microbial communities in water in different regions at different times and analyzes their interrelationships.The result is as follows:(1)In the dry season,the physicochemical properties of water near the typical area of the Jialing River Basin,such as temperature and pH,are significantly different from those in the wet season,but the regional differences are not significant during the same period.In the dry season,the dissolved oxygen mean value is lower than in the wet season,and the nitrogen mean value is slightly higher than in the wet season,but the total phosphorus content is not significantly different between the two periods.The total nitrogen,ammonium nitrogen,and total phosphorus of the water near the farmland,residential areas,and park squares are relatively high during the dry and wet season,but the nitrate nitrogen and nitrite nitrogen meet the drinking water standards in different periods.(2)The high-throughput sequencing revealed that in the dry season the microbial communities included 272 phylum,576 classes,871 orders,1324 families,2522 genera,and 4160 species,and the wet season included 226 phylum,441 classes,791 orders,1150 families,2426 genera,and 3923 species;Judging from the microbial abundance and diversity of water,the dry season is slightly higher than the wet season.There arealso differences in microbial diversity and abundance of water in different periods and regions,the dry season show a residential area > Farmland > Park Plaza > Hospital >Scenic Area,and another is a hospital > Residential Area > Farmland > Park Square >Scenic Area.(3)The analysis of the microbial community structure of water in different periods and regions shows that the species of dominant bacteria groups in the two periods are basically the same.Because the physicochemical properties of water in different regions are different,the dominant bacteria groups also show spatial differences in the same period.(4)Further analysis of the relationship between the composition of microbial community in water and environmental factors shows that the positive and negative correlations between the dominant bacteria groups in the dry season and the wet season are different from each other.Nutrients such as nitrogen and phosphorus are abundant in residential areas and farmland,the dominant bacteria groups have positive correlation with nutrients.However,the concentration of nitrogen and phosphorus in the water near the hospital is low,and its dominant bacteria group are negatively related to nutrients.During the dry season and the wet season,the correlation between nutrients and dominant bacteria groups of Acinetobacter,hgcI-clade,Limnohabitans and so on in the water was significant(p < 0.05).Flavobacterium and Novosphingobium are positively related to temperature,pH,and ammonium nitrogen.It is shown that human activities and other factors have a greater impact on the physicochemical properties of water,and multiple environmental factors jointly affect the microbial community structure in water,resulting in time and space differences in microbial community.The research results can provide a theoretical basis for further protecting the ecological environment of the water body and developing and using the water resources of the Jialing River,and also have a certain guiding role for industrial and agricultural production in the Jialing River basin and its surroundings.