青藏高原冰尘微生物介导的碳代谢及环境效应

Microorganisms growing and reproducing in cryoconite holes are always associated with low temperature and intense radiation. The microorganisms driven carbon metabolism determine the amount of organic carbon in the glacier. In the milieu of global warming, they are also expected to enhance the ecological and environmental effects due to glacial melt. This proposal targets at one of the core science questions within the Key Research Project to unravel the mechanism of how microorganisms drive element circulation on earth. The proposed research will focus on the adaptation strategy of cryoconite microorganisms to cold and strong radiation and their roles in carbon cycle and environmental effects in extreme glacier environments. We will study the biodiversity of glacial cryoconite microorganisms in 20 glaciers in different geographical and climatic regions across the Tibetan Plateau (TP), combined with fixed-sited observation on two glaciers and laboratory experiments, this research aims to understand the dominant microorganism groups and their environmental adaptation characteristics in cold and radiation-resistant cryoconite holes, as well as the carbon metabolism process and potential of microorganisms in cryoconite holes and their interaction with the unique environment of the TP. The results are expected to reveal the roles of cryoconite microorganisms in the glacial carbon cycle, estimate its biogeochemical influences on the glacier change, explore the roles and biogeochemial significance of cryoconite microorganisms in carbon cycle in glaciers, and shed light on the prediction of the quantity of organic carbon transported from the glacier to the downstream ecosystem, as well as the evolution mechanism of microorganisms under radical environments.

冰尘微生物生存在低温、强辐射的冰川冰尘穴中，其所介导的碳代谢过程决定了冰川有机碳量的多少，且与全球增温效应叠加增强冰川消融。本项目针对“水圈微生物驱动地球元素循环的机制”重大研究计划的核心科学问题—微生物驱动地球元素循环的机制，选取剧烈变化中的青藏高原冰川，聚焦冰尘微生物适应寒冷强辐射的生存策略和微生物介导的碳代谢过程及环境效应，综合应用最新的冰川地理与微生物学交叉技术手段，通过对青藏高原不同自然地理和气候区内的20条冰川冰尘微生物研究，结合2条冰川的定点观测和室内实验，明确冰尘穴耐低温耐辐射优势微生物类群及其环境适应特征，揭示冰尘微生物介导的碳代谢过程和潜力及其与青藏高原特有环境的互作机制，探讨冰尘微生物在冰川碳循环中的作用及其对冰川消融的影响。上述研究对于准确预测冰川向下游生态系统输送有机碳量等关键参数具有重要作用，对于揭示微生物在极端环境条件下的适应性进化具有重要科学意义。

申请人专注于冰川这一地球上重要的碳库，围绕冰尘微生物适应冰川极端环境策略、冰尘微生物介导的碳循环及其环境效应两个关键科学问题，结合冰川原位实验、综合微生物学、自然地理学和气候学等方法，较系统地开展了青藏高原冰川冰尘微生物介导的碳代谢及环境效应的研究，揭示了青藏高原冰川冰尘微生物群落组成和多样性，发现青藏高原的优势物种与北极和阿尔卑斯地区显著不同，并包含巨大的未知物种；揭示了冰尘微生物耐低温、耐辐射的环境适应机制，发现冰尘微生物通过色素合成、膜转运、蛋白质低温柔性改变等功能以适应低温、强紫外辐射的环境。揭示了冰尘微生物参与的碳代谢过程，发现溶解性有机碳组分存在明显空间分异，这与微生物参与的固碳和碳分解等过程相关。揭示了冰尘微生物及其代谢过程的环境效应，发现冰尘微生物产生大量色素加速冰川消融，随着冰川消融，冰尘微生物中高丰度的耐药菌释放到下游生境中，对生态安全和人类健康具有潜在风险。