浑河底泥产甲烷古菌多样性空间分布特征

Spatial distribution of methanogenic archaea diversity in the sediments of Hun River

为了深入探究影响河流甲烷排放的关键因素,采用PCR-RFLP(限制性片段长度多态性聚合酶链反应)技术及测序分析对浑河底泥产甲烷古菌的多样性及空间分布进行了研究.结果表明,浑河底泥产甲烷古菌划分为4大类群:甲烷杆菌目(Methanobacteriales)、甲烷微菌目(Methanomirobiales)、甲烷胞菌目(Methanocellales)和甲烷八叠球菌目(Methanosarcinales).从河流上游到下游,产甲烷古菌的群落结构呈现出空间变异的特征.河流上游占优势的产甲烷古菌菌属为Methanosarcina和Methanospirillum,分别约占46.2%和20.8%;中游主要菌属为Methanosarcina、Methanobacterium和Methanomethylovorans,分别约占40.9%、20.7%和15.2%;下游主要菌属为Methanosarcina和Methanobacterium,分别约占46.7%和22.1%.浑河底泥中Methanosarcina为优势菌属.Shannon指数(H')和Simpson多样性指数(D)计算结果表明,河流上游(H'=1.56,D=0.33)和中游(H'=1.79,D=0.26)产甲烷古菌的多样性与下游(H'=1.65,D=0.32)均较为接近.

To understand the key factors influencing methane emissions from river, the spatial distribution and diversity of methanogenic archaea in the sediments of Hun River were investigated using PCR-Restriction Fragment Length Polymorphism（ PCR-RFLP ） and sequencing Phylogenetic analysis. The results showed that methanogenic archaea communities in the sediments could be divided into four groups, Methanobacteriales, Methanomirobiales, Methanocellales and Methanosarcinales. Community structure of methanogenic archaea indicated spatial variability form upstream to downstream. The sediments of upstream were Methanosarcina and Methanospirillum, which accounted for 46.2% and 20.8% of total methanogens, respectively. Main genera present in the sediments of midstream were Methanosarcina, Methanobacterium and Methanomethylovorans, which accounted for 40.9%, 20.7% and 15.2% of total methanogenic archaea, respectively. In the sediments of downstream, main genera present were Methanosarcina and Methanobacterium, which accounted for 46.7% and 22. 1% of total methanogenic archaea, respectively. All in all, the main genera in sediments of Hun river were Methanosarcina. Shannon index （H＇） and Simpson diversity index （D） suggested that diversity of methanogenic archaea in upstream （H＇= 1.56, D = 0.33 ） and midstream （ H＇ = 1.79, D = 0.26） were relatively close to downstream （ H＇ = 1.65, D = 0.32）.