Respones Of Microbial Community Structure And Environment Factors In Qixing River Wetland

As one of the most important components in wetland ecosystem,microorganisms play an important role in nutrient cycling in soil,soil composition and soil ecological restoration.Microorganisms are senstive to environmental changes,and mainly through microbial community composition and diversity to take on.microbial community structure and diversity are important environmental factor to evaluate soil environment changes.Qixing River wetland is typical and primitiveness representative in Sanjiang Plain.In recent years,due to upstream agricultural development and human factors interference,the area of Qixing River wetland decreased,and biodiversity decreased.Therefore,the study on microbial community structure and diversity,the response relationship between environmental factors and microorganisms are far-reaching significance for wetland ecosystem restoration.This study was carried out in Qixing River wetland in northeast of China,the soil samples from returning farmland to wetland as research areas,and the soil samples from natural wetland and returning farmland to forest as comparison areas in Qixing River wetland.Study on the changes of physical and chemical properties in wetland soil,using the traditional microbial culture method to determine the microorganisms numbers,microbial community structure was determined by high throughput sequencing technology,and analysis the dynamic changes between microorganisms numbers and community composition,the correlation between microbial and physicochemical properties.The purpose of the study is to privode theoretical support for microbial resources development in wetland restoration process in the Sanjiang Plain.The analysis of soil physical and chemical properties(pH,OM,TS,TN,TP,SWC)indicated that the contents of organic matter,total salt,total nitrogen,and total phosphorus in returning farmland to wetland are significantly higher than the natural wetland and the returning farmland to wetland to forest.Returning farmland to wetland can promote the improvement of soil nutrients.The correlation analysis indicated that pH,TS,TN,TP,OM,and SWC showed a certain correlation,indicating that C and Nelements have the promotion or inhibition in the global biochemical cycle.The analysis of microorganisms numbers indicated that the contents of bacteria were the most abundant in the soil environment in Qixing River wetland,followed by actinomycetes and fungi,Returning farmland to wetland can promote the improvement of microorganisms numbers,the correlation between microbial numbers and soil physicochemical properties indicated that the numbers of microbes increased with the increase of TS,and decreased with the increase of SWC.High throughput sequencing technology is applied to the analysis of microbial community composition,the 185601 sequence belongs to 12 different phylum,mainly including Proteobacteria,Acidobacteria,Actinobacteria,Bacteroidetes,Chloroflexi,Firmicutes,Verrucomicrobia,Gemmatimonadetes,Nitrospirae,Planctomycetes,Cyanobacteria,Saccharibacteria.Proteobacteria(20.75% ~ 32.63%),Acidobacteria(14.38% ~ 33.95%),and Actinobacteria(11.36% ~ 19.00%)were dominant phylum.Acidobacteria,Actinobacteria,Alphaproteobacteria,Betaproteobacteria,Deltaproteobacteria were mainly class.The dversity analysis showed that the Ace,Chao,and Shannon diversity index in returning farmland to wetland were higher than natural wetand and returning farmland to forest,returning farmland to wetland increased microbial community diversity.The correlation between soil physical and chemical properties and microbes indicated the microbial diversity and the distribution of microbial in Qixing River wetland were the result of the interaction of various environmental factors.that organic matter,total salt,total nitrogen,and total phosphorus were mainly factors affecting the Shannon diversity index,total nitrogen had a great effect on the distribution of Proteobacteria,organic matter,total nitrogen and total phosphorus had main influence on the distribution of Acidobacteria,total phosphorus was the main factor affecting the distribution of Actinobacteria.