【作者】 张林宝；

【导师】 李铁刚； 党宏月；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋生物学， 2009， 硕士

【摘要】 为研究鄂霍次克海天然气水合物区沉积物古菌、甲烷厌氧氧化古菌和硫酸盐还原细菌的多样性分布,我们以PCR技术为基础构建mcrA、dsrAB和古菌16S rRNA基因文库。对所获得的序列进行系统进化和统计学分析发现:鄂霍次克海古菌类群主要为Marine Benthic Group D (MBG-D)、Marine Benthic Group B (MBG-B)、Marine Crenarchaeotic Group I(MG- I),另外少量古菌16S rRNA基因序列为Anaerobic Methanotrophs 2c(ANME-2c),主要分布在LV39-25H岩心的表层沉积物中。LV39-40H岩心表层的古菌群落结构与其他六个层位古菌群落结构相比有着显著的差异。mcrA基因序列主要为催化甲烷厌氧氧化的古菌ANME-2(c和d簇),在所研究的各个层位的沉积物中均广泛分布。少量的ANME-1(a簇)发现于LV39-40H岩心表层以下的沉积物中。产甲烷古菌数目不多,集中分布在LV39-25H岩心200cm和LV39-40H岩心180cm的沉积物中。dsrAB基因文库分析表明硫酸盐还原细菌种类丰富,表层沉积物中硫酸盐还原细菌多样性最高。在两个岩心所有层位的沉积物中都有一定数量的克隆属于DSS簇,它们可能与ANME共生催化甲烷的厌氧氧化作用。总之,所有数据表明在鄂霍次克海天然气水合物区存在着较活跃的甲烷厌氧氧化作用,揭示了参与甲烷厌氧氧化作用的微生物群落结构和多样性。为研究东海内陆架闽浙沿岸泥质区不同深度沉积物中古菌群落垂向分布特征,通过古菌16S rRNA基因文库共得到473个有效克隆50个OTUs (Operational Taxonomic Units)。16S rRNA基因序列系统进化和统计分析发现古菌分别归属于泉古生菌(Crenarchaeota)和广古生菌(Euryarchaeota),其中以Miscellaneous Crenarchaeotic Group(MCG)为主,仅含少量的MBG-B、South African Gold Mine Euryarchaeotic Group(SAGMEG)、ANME-3、MG- I和MBG-D。该泥质区沉积物可能存在由ANME-3催化的甲烷厌氧氧化作用,同源序列分析表明其古菌群落分布与周边环境有较大联系。UniFrac与沉积物环境因子分析表明该泥质区古菌群落垂向分布与沉积物有机质含量和粒度变化密切相关。通过对比发现,鄂霍次克海天然气水合物区甲烷厌氧氧化古菌主要为ANME-2和少量的ANME-1,而东海内陆架泥质区甲烷厌氧氧化古菌仅为极少量的ANME-3;鄂霍次克海天然气水合物区广古生菌和泉古生菌数量各占一半,主要为MBG-D、MBG-B、MG-I。东海内陆架泥质区沉积物古菌序列主要为泉古生菌(MCG)。海域类型的不同以及有机碳含量等环境因子的差异可能是这两个海域古菌群落结构差异的主要原因更多还原

【Abstract】 To identify the distribution and diversity of archaea, methanotrophs and sulfate-reducing bacteria (SRB) in the gas hydrate bearing sediments of the Okhotsk Sea, we investigated the diversity of archaeal 16S rRNA, mcrA, dsrAB genes sequences by using a PCR-based cloning approach. Phylogenetic and statistic analysis of clone sequences showed that: The majority of archaeal phylotypes were Marine Benthic Group D (MBG-D), Marine Benthic Group B (MBG-B) and Marine Crenarchaeotic Group I (MG I). Additional few sequences fell into Anaerobic Methanotrophs 2c (ANME-2c), which was mainly detected from the surface layer of core LV39-25H. The archaeal communities of the surface layer of core LV39-40H significantly distinct from those of other six depth layers. mcrA gene clone libraries showed that the ANME population consisted predominantly of ANME-2 methane oxidizers (group c and d) at each studied layers; few ANME-1 community (group a) were found coexist with ANME-2 below the surface sediments of core LV39-40H. Few methanogens were mainly retrieved from 200cm layer of core LV39-25H and 180cm layer of core LV39-40H. Clones libraries of dsrAB gene displayed the diversified SRB community composition, especially in the surface layers of the two cores. Quite a number of dsrAB clones, recovered from all layers of the two cores, were affiliated with the DSS group (Desulfosarcina and Desulfococcus), which may form consortia with ANME archaea. Generally, the data analysed here show active anaerobic oxidation of methane in the Okhotsk Sea gas hydrate, and reveale the distribution and diversity of the involved microbe.Archaeal 16S rRNA gene clone libraries were constructed from different depth layers sediments to elucidate the distribution and diversity of archaea in the Zhejiang and Fujian coastal mud wedge of the inner continental shelf of the East China Sea. We obtained 473 useable clones and 50 different OTUs (Operational Taxonomic Units). Phylogenetic and statistic analysis of clone libraries showed that: archaeal 16S rRNA gene sequences were within phylums of Crenarchaeota and Euryarchaeota, respectively. The majority of archaeal phylotypes were Miscellaneous Crenarchaeotic Group (MCG), Additional few sequences fell into MBG-B, South African Gold Mine Euryarchaeotic Group (SAGMEG), ANME-3, MG-I and MBG-D. There might be anaerobic oxidation of methane carried out by group ANME-3 in this mud wedge. Homologous sequences analyses showed that the distribution of archaea in this mud wedge was related to the surrounding environment. UniFrac analysis and sediment environmental parameters indicated that the vertical distribution of archaea was intimately coincided with the variation of sediment total organic carbon content and grain size.Comparative analysis demonstrated that: Anaerobic Methanotrophs located at the gas hydrate bearing Oktostk Sea were mainly ANME-2 and few ANME-1, while the counterparts located at mud wedge sediments in the East China Sea were just few ANME-3. In the gas hydrate bearing Oktostk Sea, Crenarchaeota and Euryarchaeota each accouted for half of the total archaeal sequences. The majority of archaeal phylotypes were Marine Benthic Group D (MBG-D), Marine Benthic Group B (MBG-B) and Marine Crenarchaeotic Group I (MG-I). Archaeal sequence obtained from mud wedge sediments in the East China Sea mainly belonged to the phylum of Crenarchaeota (MCG). The type of sea areas and various environment factors, such as total organic carbon content, may be the explanation for the difference of archaral community.更多还原