黄河源区高寒沼泽湿地土壤微生物群落结构对不同退化的响应

Responses of Different Degradation Stages of Alpine Wetland on Soil Microbial Community in the Yellow River Source Zone

为研究高寒沼泽湿地退化过程中土壤微生物群落多样性的变化,应用MiSeq高通量测序技术,分析高寒沼泽湿地退化过程中土壤微生物群落多样性以及相关的环境因子.结果表明,高寒沼泽湿地退化改变了土壤微生物在OTUs水平上的物种组成,OTUs种类变化丘间较冻融丘明显,且土壤真菌OTUs种类变化显著;冻融丘和丘间细菌微生物多样性指数大于真菌微生物;不同退化高寒沼泽湿地土壤优势微生物种类相同,细菌为变形菌门(Proteobacteria)和RB41,真菌为子囊菌门(Ascomycota)和被孢霉属(Mortierella),除RB41外未退化与重度退化间优势微生物丰度有较大差异(P<0.05),丘间的优势微生物对不同退化较冻融丘敏感;土壤含水量、有机碳、微生物碳、微生物氮和莎草科的盖度是影响土壤微生物群落结构的主要因素.综上所述:高寒沼泽湿地退化导致微生物多样性降低,在湿地恢复中应加强湿地冻融丘和莎草科植物的保护以及土壤水分、有机碳和微生物碳氮的补充.

MiSeq sequencing technology was used to analyze the microbial community diversity of soil in alpine wetlands to understand the degradation processes and environmental factors in these areas.The results showed that the severity of soil degradation changed the species diversity of soil microorganisms at the level of OTUs,and grass patches contained more species than frozen-thawing patches.The soil fungi species of OTUs changed significantly.The diversity indexes of bacteria(between the frozen-thawing patches and the grass patches)were higher than that of fungi.The dominant microbial species were consistent among different degradation stages.The dominant species of bacteria and fungi were Proteobacteria and RB41,and Ascomycota and Mortierella,respectively.The abundance of dominant microorganisms was significantly between un-degraded and heavily degraded areas,except for RB41(P<0.05).The dominant microorganisms in the grass patches were more sensitive than those in the frozen-thawing patches.It was found that the main factors affecting the microbial community structure of soil were water content,organic carbon,microbial biomass carbon,microbial biomass nitrogen,and sedge coverage.Microbial diversity may decrease in heavily degraded alpine wetlands.Thus,the frozen-thawing patches and sedge species should be first protected,and the supplements of soil water content,soil organic carbon,microbial biomass carbon,and nitrogen should be strengthened for alpine wetland restoration.