祁连山冻土区天然气水合物DK-2钻孔微生物群落

摘要

Eleven cores from DK-2 gas hydrate borehole in Qilian Mountain permafrost, located in the north of the Tibetan Plateau, were investigated to find out the difference between gas hydrate samples and non-gas hydrate samples by microbial community analysis. Of all the genes often found in marine gas hydrate samples, I.e., bacterial and archaeal 16S rDNA, mcrA (Ⅰ ,Ⅱ), pmoA, mmoX and mxaF, bacterial 16S rDNA could be observed in all of the eleven samples, resulting in the detection of a great quantity of bacterial sequences belonging to 5 phylums, I.e., Proteobacteria, Actinobacteria, Bactemides, Firmicules, and Deinococcus-Thermus. The bacteria diversity decreases with the increasing depth. A study of gas hydrate sample DK2-19 and non-gas hydrate sample DK2-25 selected for phylogenetie analysis and diversity comparison shows that the two samples are remarkably different from each other. A comparison between gas hydrate samples and non-gas hydrate samples show that the percentage of γ-Proteobacteria in gas hydrate samples is lower than that in non-gas hydrate samples, and Arthrobacter could be found mainly in non-gas hydrate samples.%对青海省祁连山永久冻土区天然气水合物DK-2钻孔的11件样品进行分析,通过微生物群落分析来探寻水合物层样品与非水合物层样品的差别.在11件样品中均发现了细菌16S rDNA,未检测到海洋天然气水合物地区常见的古菌16S rDNA、mcrA(Ⅰ,Ⅱ)、pmoA、mmoX和mxaF.分析得到的细菌16S rDNA分属5个门,包括变形杆菌门、放线菌门、拟杆菌门、厚壁菌门和异常球菌-栖热菌门,随着样品深度的增加,细菌多样性有降低的趋势.对非水合物层样品DK2-19和水合物层样品DK2-25进行细菌系统发育树分析,发现这2个样品群落结构相差较大.水合物层样品与非水合物层样品细菌群落对比后发现,水合物层样品中γ-变形杆菌的比例低于非水合物层样品中γ-变形杆菌的比例,而Arthrobacter属多发现于非水合物层的样品中.