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祁连山冻土区是我国青藏高原重要永久冻土区之一,也是我国陆域天然气水合物分布的重要地区。前期调查表明祁连山木里天然气水合物钻井区一带具有丰富多样的高寒冻土生态类型。为了解该地区高寒草甸和高寒沼泽草甸表层土壤中古菌群落的多样性及分布特征,对2014年初冬在该区采集的表层土壤样品利用16S rRNA分子生物学技术和地球化学等方法进行了分析和研究。结果显示,高寒草甸区土壤呈中性,而高寒沼泽草甸区土壤呈弱酸性。钻井区土壤中的TOC和顶空气甲烷含量均显著高于背景区,而在背景区内的两种生态类型土壤中的TOC和顶空气甲烷含量差别较小。钻井区(除1个点)微生物细胞丰度高于背景区2~5倍。冬季表层土壤中的古菌多样性较低,含泉古菌的3个类群和广古菌的3个类群。不同植被类型古菌群落的优势种群显著不同,在高寒草甸区为泉古菌门的GroupⅠ.1b,而高寒沼泽草甸区为广古菌门的甲烷八叠球菌目(Methanosarcinales)。根据研究结果推测,土壤水分可能是导致高寒草甸区和高寒沼泽草甸区细胞丰度和古菌群落差异的一个主要原因,高寒沼泽草甸区内产甲烷菌占优势可能与土壤高TOC含量有关。高寒沼泽草甸土壤中存在较丰富的产甲烷古菌,它们在厌氧条件下的甲烷氧化作用也是土壤中甲烷来源之一。
The Qilian Mountains permafrost zone is one of the important permafrost regions in the Qinghai-Tibet Plateau and also an important area for the distribution of gas hydrate in China’s terrestrial areas. Preliminary investigations show that the Muli gas hydrate drilling area in the Qilian Mountains has a rich and varied type of permafrost ecology. In order to understand the diversity and distribution of archaeal community in surface soils of alpine meadow and alpine marsh meadow in this area, 16S rRNA molecular biology techniques and geochemical methods were used to analyze the surface soil samples collected in this area in early 2014, analysis and research. The results showed that the soil in the alpine meadow was neutral, while the soil in the alpine meadow was weakly acidic. The contents of TOC and headspace methane in the drilling soil were significantly higher than those in the background area, while the contents of TOC and the headspace methane in the two ecotypes in the background area differed slightly. Drilling area (except 1 point) microbial cell abundance higher than the background area 2 to 5 times. In winter, the archaeal diversity in surface soils is low, including three archaeal groups of archaea and three archaeal groups of archaea. The dominant populations of archaeal communities of different vegetation types were significantly different, belonging to GroupⅠ.1b of Quercus, in the alpine meadow and Methanosarcinales in the alpine swamp meadow. According to the results of the study, it is speculated that soil moisture may be one of the main causes of cell abundance and archaeal community differences in alpine meadow and alpine marsh meadow. The predominance of methanogens in the alpine meadow may be related to the high TOC content related. Algae marsh meadow soil rich in methanogenic archaea, their methane oxidation under anaerobic conditions is also one of the sources of methane in the soil.