祁连山木里水合物钻区古菌群落年际（2013-2014年）变化特征

发布时间：2018-08-07 06:32

【摘要】：天然气水合物作为21世纪的一种新兴潜在替代能源已备受关注。以往国际上对冻土区天然气水合物的勘查,关注点多在储层中水合物的赋存状况及多年冻土层与水合物成藏间的关系等方面。近年来,随着研究的深入,科学家们已经认识到冻土微生物活动对水合物分布及冻土环境的重大影响,但研究程度仍十分薄弱。本文利用我国首个陆域天然气水合物钻区,通过采集钻孔周边7个点位的土壤样品,利用吖啶橙染色直接计数法评估土壤样品中微生物细胞丰度；同时提取土壤样品中微生物细胞的DNA,扩增古菌16S rRNA基因,对所得克隆序列进行系统发育进化分析,并就2013年和2014年古菌群落组成、年际变化以及不同生态环境条件下古菌类群的差异做了详细的对比分析。研究发现,祁连山木里地区的古菌主要是由泉古菌和广古菌组成,其中泉古菌包含Group 1.1b、Groupl.3和少量热变形菌目(Thermoproteales)。广古菌包含的古菌类群有甲烷微菌纲(Methanomicrobia)、热原体纲(Thermoplasmata)和少量的甲烷杆菌纲(Methanobacteria)。Group 1.3为整个群落的优势类群,甲烷微菌纲(Methanomicrobia)为广古菌中的优势类群。整体来看,表层古菌群落多样性要高于次表层,表层一般含有较多的Group 1.1b类群,次表层一般含有较多的Group1.3类群。Group 1.1b和热变形菌目(Thermoproteales)与含水率、电导率和顶空气甲烷含量都有较为明显的负相关关系,广古菌门中的产甲烷菌则一般与温度、含水率以及顶空气甲烷含量呈正相关。除个别采样点外,大部分采样点古菌类群分布特征都有着较大的年际变化,尤其是次表层区域。2014年次表层产甲烷古菌的分布含量相较于2013年有着大幅度的上升(11.6%)。不同生态环境下古菌群落结构差异十分明显,草甸区一般含有较多的Group 1.1b且一般不含产甲烷菌,沼泽区优势类群一般为Group 1.3。总而言之,本研究得出的多个结论为今后在冻土区开展冻土微生物的相关研究提供了一定的数据基础和参考依据。
[Abstract]:As a new potential alternative energy source in the 21st century, gas hydrate has attracted much attention. In the past, the international exploration of gas hydrate in permafrost region focused on the occurrence of gas hydrate in reservoir and the relationship between permafrost and gas hydrate accumulation. In recent years, with the development of research, scientists have recognized the great influence of microbial activities on hydrate distribution and permafrost environment, but the degree of research is still very weak. In this paper, using the first land gas hydrate drilling area in China, the microorganism cell abundance in soil samples was evaluated by acridine orange staining direct counting method by collecting soil samples at 7 points around the borehole. At the same time, the DNA of microorganism cells was extracted from soil samples, the 16s rRNA gene was amplified, the cloned sequences were phylogenetic and phylogenetic analysis, and the composition of the ancient bacteria communities in 2013 and 2014 were analyzed. The year-to-year variation and the differences of paleoflora under different ecological conditions were compared and analyzed in detail. It is found that the ancient bacteria in Muli area of Qilian Mountain are mainly composed of Quangu and Guangu. Among them, Quanggu contains Group 1.1b, Groupl.3 and a small amount of (Thermoproteales). The palaeomycetes contained (Methanomicrobia), (Thermoplasmata) and a small number of methanobacterium (Methanobacteria). 1. 3 were the dominant groups of the whole community, and (Methanomicrobia) was the dominant group in the whole community. On the whole, the diversity of palaeomycetes community in the surface layer was higher than that in the subsurface layer. The surface layer generally contained more Group 1.1b group, and the subsurface layer generally contained more Group1.3 group .1b, (Thermoproteales) and moisture content. There was a significant negative correlation between electrical conductivity and methane content in the top air, while there was a positive correlation between the methanogenic bacteria and temperature, moisture content and methane content in the top air. With the exception of individual sampling sites, the distribution characteristics of paleomycetes in most sampling sites showed great interannual variation, especially in subsurface areas. The distribution of methanogenic palaeomycetes in 2014 was significantly higher than that in 2013 (11.6%). The community structure of palaeomycetes in different ecological environments was very different. In meadow area, there were more Group 1.1b and no methanogenic bacteria, and the dominant group in swamp area was Group 1.3b. All in all, the conclusions of this study provide a certain data basis and reference for the future research on frozen soil microbes in frozen soil regions.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：Q913;P618.13

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