基于QMEC分析的青藏高原不同类型冰川前缘地土壤微生物功能潜力

微生物通过多种功能代谢过程主导着因气候变暖裸露的冰川前缘地土壤元素的地球化学循环.以青藏高原的海洋型冰川、亚大陆型冰川和极大陆型冰川的前缘地土壤为研究对象，分析不同类型冰川前缘地土壤的微生物功能特征.依次选择玉龙冰川、天山乌鲁木齐1号冰川和老虎沟12号冰川作为三类冰川的典型代表，采用高通量功能基因芯片(QMEC)检测土壤微生物的功能基因特征.结果表明，在三类冰川前缘地土壤中，半纤维素降解基因和还原型乙酰辅酶A途径相关的碳固定基因丰度最高，三者主要的氮功能基因和氨化作用有关，磷、硫功能基因则主要与有机磷矿化过程和硫氧化过程相关.其中，水热条件较好的海洋型冰川的微生物功能基因的种类与丰度最高，其次为环境较为干燥的极大陆型冰川.三类冰川前缘地土壤的微生物功能基因结构的显著差异，证实了地理环境差异对微生物功能特征的影响，也为不同类型冰川前缘地土壤微生物的功能及其介导的元素地球化学循环研究提供了基础.

QMEC-based Analysis of the Soil Microbial Functional Potentials across Different Tibetan Plateau Glacier Forelands

Soil microorganisms dominate the biogeochemical cycles of elements in glacier forelands, which continue to expand due to the climate warming. We analyzed the soil microbial functional characteristics among three types of glacier forelands on the Tibetan Plateau: Yulong Glacier (Y), a temperate glacier; Tianshan Urumqi Glacier No.1 (T), a sub-continental glacier; and Laohugou Glacier No.12 (L), a continental glacier. Here, soil microbial functional genes were quantified using quantitative microbial element cycling technology (QMEC). We found that, in the three glacier forelands, the abundances of soil microbial functional genes related to hemicellulose degradation and reductive acetyl-CoA pathway were highest compared with other carbon-related functional genes. The main nitrogen cycling genes were involved in ammonification. The functional genes of the phosphorus cycle and sulfur cycle were related to organic phosphate mineralization and sulfur oxidation. Furthermore, the soils of the temperate glacier foreland with better hydrothermal conditions had the most complex microbial functional gene structure and the highest functional potentials, followed by those of the soils of continental glacier foreland with the driest environment. These significant differences in soil microbial functional genes among the three types of glacier forelands verified the impacts of geographic difference on microbial functional characteristics, as well as providing a basis for the study of soil microbial functions and biogeochemical cycles in glacier forelands.