The Structure Of Methanogen Communities In Marsh Soil Of Salinity Gradient In The Min River Estuary And Response To Environmental Factors

Estuary which located in the intersection of river and ocean is an important part of natural wetland, it can be used as a model environment for microbial community study in wetlands. Methanogenic archaea are functional bacteria of Methanogenesis which play an important role in methane metabolism. Salinity is an important environmental factor in estuaries, therefore, salinity changes on the influence of methanogens in estuarine tidal marsh wetlands has an important ecological significance. In this paper, using the C. malaccensis marshes of MinRiver estuary as the research object, through the extraction of soil DNA, PCR amplification of mcrA genes, establishing of clone library, restriction fragment length polymorphism, sequencing, real-time PCR and a series of molecular biological techniques, we study the methanogenic archaea community structure and abundance from the soil of the tidal freshwater and brackish Cyperus malaccensis marshes in the Min River estuary, southeast China. Its response to salinity, Ph, Eh and SOC was also studied. Discussing the community structure of Methanogenic archaea in the Cyperus malaccensis marshes. The main content and research result of this paper are as follows:(1) The communities of methanogens in the C. malaccensis marshes were mainly divided into three groups which were Methanomicrobiales, including Methanoregula, Methanolinea, Methanoplanus, Methanoculleus, Methanofollis, Methanogenium; Methanosarcinales, including Methanosarcina, Methanococcoides, Methanolobus, Methanomethylovorans, Methanolobus and Methanobacteriales, including Methanobrevibacter, Methanobacterium. Methanoregula are the dominant groups in the Min River estuary marsh, which account for the proportion of44.1%.(2) The analysis of mcrA gene of Methanogenic archaea clone library, we can conclude that The community structure of methanogen in the tidal C. malaccensis marshes changed with salinity. The freshwater C. malaccensis marshes were mainly dominated by Methanoregula, Methanolinea, Methanosarcina and Methanobacterium. However, though the brackish C. malaccensis marshes mainly dominated by Methanoregula, Methanolinea, Methanosarcina and Methanobacterium, it was mainly dominated by Methanoregula. The abundance of Methanogenic archaea in the tidal freshwater of Xiayangzhou and Tajiaozhou wetlands and in the brackish of Bianfuzhou and Shanyutan wetlands in the Min River estuary have significant difference, its range was between3×107and56×107copy g-1.The relation between soil factors and community composition of methanogen were analysised based on CCA. It showed that the community composition of methanogen has a significant correlation with salinity and SOC (P(Electrical conductivity)=0.041, P(SOC)=0.045), no significant correlation with pH and Eh. The relation between soil factors and abundance of methanogen were analysised based on the variance. It showed that the abundance of methanogen decreased with increasing of sality (R2=0.513, P<0.05),and did not correlate with the SOC、pH and Eh (P (SOC=0.742,P (pH)=0.794, P (Eh)=0.781。...