天山1号冰川活性微生物谱系结构的生境演替及群落功能属性的空间分异

冰川即是一个相对封闭的生态系统，也是一个开放的体系。自上而下的融水径流将大气沉降、冰川表面与底部生态系统耦联，但并不清楚整个生态系统活性微生物谱系结构与群落功能属性的时空关联性。本项目基于细菌、真菌全长rDNA、rRNA及功能微生物持家基因的高通量测序和定量PCR技术，精准解析天山1号冰川(冷性冰川)不同生境(大气沉降物、表面积雪、冰层、冰尘、融水及底部沉积层和前沿径流)的活性微生物谱系结构与丰度差异；同时通过多组学比较，表征冰川不同生境介导C、N、S关键元素循环功能基因谱的空间分布特征，阐明大气沉降外源微生物和冰川表面、冰川底部等发生的生态学过程的关联性。进而采用生态多元统计分析和系统网络模型构建，在谱系结构和功能属性两个层面揭示冰川生境微生物多样性格局演替和空间分异的驱动机制。为科学评价干旱区典型的亚大陆型冷冰川生态系统对全球气候变暖的响应，区域环境变化趋势的预测提供理论参考依据。

Glacier ecosystems contain multiple key sub-ecosystems and biomes, including the supraglacial ecosystem (cryoconite, ice, surface snow cover and melting water runoff), the subglacial ecosystem (sediments and water beneath glaciers), interior englacial ice, proglacial streams derived from supra and subglacial runoff and atmospheric depositions. There has been compelling evidence that subglacial environments are inhabited by unique, diverse and metabolically active microbial populations that facilitate redox reactions and chemical weathering at the glacier bed. The supraglacial ecosystem is characterized by a large number of active microbial communities (usually cyanobacteria, microalgae, phytoflagellates, fungi, and aerobic heterotrophic bacteria) within the snowpack, supraglacial streams, melt pools (cryoconite holes) and moraines. At the height of summer, surface meltwater descends by supraglacial and englacial crevasses, moulins and cracks to the glacier bed, which facilitates the flow of organic matters, nutrients and microorganism throughout the ecosystem. Therefore, there are immediate connections between supraglacial, englacial, subglacial, proglacial habitats and atmospheric depositions. However, to date, spatio-temporal relationship and turnover of active function microbes and their biogeochemical process between multiple key sub-ecosystems and biomes remains limited..The objective of this project is to determine the variability of the structure, functions, activities and dynamics of microbial communities among the supraglacial, interior englacial ice, proglacial catchment and subglacial habitats of the Glacier No.1 in the Tianshan Mountains (cold-based glacier). To achieve this, several parallel and complementary state-of-the-art-approaches will be combined, e.g. metagenome and metatranscriptome-based on Illumina MiSeq, single-cell sequencing, PacBio single molecule sequencing (SMRT) for full-length 16S rRNA(c-DNA) and 16S rDNA(g-DNA) and quantitative PCR (q-PCR). .To conclude, our objectives are: (Ⅰ) to elucidate core, variable and habitat-specific microbiota of subglacial outflow, subglacial sediments, supraglacial runoff, supraglacial cryoconite, snowpack and proglacial catchment. (Ⅱ) to determine association of functional gene profiles on metabolic and biogeochemical processes of the nitrogen, carbon and sulfur cycling in the various habitats of the Glacier No.1. (Ⅲ) to gain insight into genomic characteristic of key sulfur-cycling active functional microbes in subglacial habitats of the Glacier No.1. (Ⅳ) to clarify ecologically driven mechanism of microbial community assembly and succession in the various habitats of the Glacier No.1..The implementation of the project contributes greatly to our understanding of how the ecosystem processes of receding glaciers varies in response to global climate change, and thereby possibly shedding light onto the tendency of environmental changes in a regionally defined landscape.