中文摘要：

用构建克隆文库的方法对珠江口沉积物中4个层位的甲烷相关古菌群落多样性特征进行研究.结果表明甲烷相关古菌群落结构主要可以分为3类,分别为Methanosaeta,Methanomicrobiales和Methanosarcinales/ANME,且其组成随沉积物深度的改变发生规律变化.Methanosaeta和Methanomicrobiales是属于乙酸和H2/CO2利用型甲烷产生菌,在克隆文库中的含量随沉积物深度的增加而减少;Methanosarcinales/ANME主要由甲烷氧化菌和甲基利用型甲烷产生菌组成,在克隆文库中的含量随沉积物深度的增加而增加.甲烷相关古菌群落结构的变化规律说明,在SMTZ区域及以上,甲烷产生以H2/CO2和乙酸型为主;在SMTZ区域以下,以甲基利用型为主;在SMTZ区域,主要是甲烷氧化过程,由古菌类群ANME-2a负责.

英文摘要：

Based on clone and sequencing of methanogen-related 16S rRNA genes,the diversity and composition of methanogen-related archaeal communities in Pearl River Estuary sediment were investigated.The phylogenetic results suggested the methanogen-related archaeal communities in the sediment were mainly composed of three types of groups,Methanosaeta,Methanomicrobiales and Methanosarcinales/ANME respectively.The variation of detected archaeal phylotypes by depth indicated that Methanosaeta and Methanomicrobiales were predominant groups above SMTZ and the content decreased by depth;Methanosarcinales/ANME was dominant group within or below SMTZ and the content increased by depth.Methanosaeta and Methanomicrobiales mainly belong to acetate-and H2/CO2-utilizing methanogen,which indicated methanogenesis above SMTZ mainly depend on acetate-and H2/CO2 as substrates.Methanosarcinales/ANME was responsible for methane oxidation and methyl group-utilizing methanogenesis,which suggested that methane oxidation and methyl group-utilizing methanogenesis were main metabolic processes within and below SMTZ.The subgroup ANME-2a also was identified as methane oxidizer in Pearl River sediment.