青海湖3种类型高寒湿地甲烷氧化菌群落特征

Community characteristics of methane-oxidizing bacteria in three types of alpine wetlands around Qinghai Lake

摘要:

【背景】甲烷氧化菌在维持湿地生态系统碳平衡方面发挥着重要作用，青海湖高寒湿地具有十分重要的生态地位，但目前有关该地区甲烷氧化菌的研究相对较少。【目的】探究不同类型高寒湿地土壤甲烷氧化菌的群落特征与驱动因素。【方法】以青海湖流域内的小泊湖沼泽湿地、鸟岛湖滨湿地、瓦颜山河源湿地为研究对象，通过高通量测序技术对土壤甲烷氧化菌进行检测。【结果】3种不同类型高寒湿地土壤甲烷氧化菌的优势菌门均为变形菌门(Proteobacteria)。鸟岛湖滨湿地与瓦颜山河源湿地的甲烷氧化菌α多样性存在显著差异(P<0.05)，而小泊湖沼泽湿地与二者的甲烷氧化菌α多样性的差异不显著(P>0.05)。LEfSe分析表明，不同类型高寒湿地共存在40个差异菌群，尤以瓦颜山河源湿地差异菌群数量最多，从门到属水平均存在显著差异。冗余分析(redundancy analysis, RDA)表明，甲烷氧化菌菌群变化的主要驱动因子为土壤温度、土壤水分、电导率。【结论】整体而言，青海湖3种类型高寒湿地土壤理化性质及甲烷氧化菌群落多样性均存在差异，且部分菌群的相对丰度具有显著性差异(P<0.05)。

Abstract:

[Background] Methane-oxidizing bacteria play a role in maintaining the carbon balance of wetland ecosystems. Qinghai Lake alpine wetland has an important ecological status, while the methane-oxidizing bacteria in this area remain to be studied. [Objective] To explore the community characteristics and driving factors of methane-oxidizing bacteria in different types of alpine wetlands. [Methods] The methane-oxidizing bacteria in Xiaobo Lake swamp wetland, Bird Island lakeside wetland, and Wayanshan river source wetland were detected by high-throughput sequencing. [Results] The dominant phylum of methane-oxidizing bacteria in the three alpine wetlands was Proteobacteria. The alpha diversity of methane-oxidizing bacteria was different between Bird Island lakeside wetland and Wayanshan river source wetland (P<0.05), while it was similar between Xiaobo Lake swamp wetland and other two wetlands (P>0.05). The linear discriminant analysis effect size (LEfSe) revealed 40 differential microbial taxa between different types of alpine wetlands, and Wayanshan river source wetland had the most differential microbial taxa from the phylum to genus level. The redundant analysis showed that the main factors influencing the community structure of methane-oxidizing bacteria were soil temperature, soil moisture, and electrical conductivity. [Conclusion] The soil physical and chemical properties, methane-oxidizing bacterial diversity, and the relative abundance of several bacterial taxa (P<0.05) have differences among the three alpine wetlands around Qinghai Lake.