青藏高原冰川消融对其末端高寒草甸甲烷循环影响的微生物机制

受全球气候变暖影响，青藏高原冰川融水增加导致冰川末端大面积的高寒草甸被淹没，转变为季节性草甸湿地。这一转变将对土壤甲烷循环和介导此过程的产甲烷菌和好氧甲烷氧化菌的群落结构及功能活性产生影响，但影响程度与微生物机制尚不清楚。因此本项目拟选取青藏高原典型冰川为研究区，采用野外原位采样、原位模拟和室内培养相结合的方法，利用稳定性同位素结合分子生物学技术研究：1）青藏高原冰川末端草甸湿地中甲烷循环微生物的地理分布和环境驱动机制；2）原位模拟冰川融水增加对其末端草甸土壤甲烷循环微生物群落的影响；3）室内培养分析不同水分条件和冰川融水增加对甲烷产生途径的影响；4）采用同位素技术研究不同水分条件和冰川融水增加对参与甲烷氧化活性微生物类群的影响。在全球气候变暖、冰川融水增加、且大气甲烷浓度不断上升的背景下，本项目对认识青藏高原地区的甲烷循环过程，准确预测全球变暖对高寒草甸生态系统碳循环的影响具有重要意义。

Affected by global warming, the increase of glacial meltwater on the Tibetan Plateau has caused large areas of alpine meadows at the end of the glacier to be submerged and converted into seasonal meadow wetlands. This transformation will affect the soil methane cycle, as well as the community structure and functional activities of methanogens and methanotrophs involved in the process, but the extent of its effect and the underlying microbial mechanisms are unclear. Therefore, we intend to select three typical glaciers on the Tibetan Plateau as research areas, using in situ field sampling, in situ simulation and laboratory incubation experiments to study the following scientific issues: 1) Geographical distribution of methane cycling microorganisms in meadow soils and its driving environmental factors; 2) The effect of increased glacial meltwater on the microbial community involved in methane cycling in alpine meadow soils; 3) The influence of different water conditions and different levels of increased meltwater on the methanogenic pathways; 4) The use of stable isotope probing technique to study the effect of different water conditions and different levels of increased meltwater on methanotrophs and other microbial populations involved in methane oxidation. Under global warming, with the increment of glacial meltwater and atmospheric methane concentration, this study can provide valuable insights into the methane cycle on the Tibetan Plateau and help to accurately predicting the impact of global warming on the carbon cycle in the alpine meadow ecosystem.