微生物对冻土生境的适应以及对全球变化和寒区工程扰动的响应:进展与展望

Microbial Adaptation to the Habitat of Permafrost and Their Responses to Global Change and Engineering Disturbance in Cold Regions: Advances and Prospects

多年冻土这一极端的生境中,温度、营养物质、冻融过程等因素深刻影响和限制着冻土中微生物生理、代谢途径和生态结构.低温胁迫下,冻土中微生物从形态、生理和生化水平发展了特殊的耐受机制.冻融过程对细胞产生直接危害,并通过调节水盐、营养条件输送而间接地影响微生物活动.寒区工程扰动下垫面和周边一定范围内冻土的水、热、力学平衡,由此也改变了微生物赖以生存的微环境,破坏了地表植被和下伏冻土中微生物的联系.寒区油气管道泄漏后严重地污染土壤,并毒害和抑制冻土中微生物.冻土区微生物数量及生物多样性的波动与冻土的后生冷生作用以及生物地球化学循环密切相关.它们可能记录了冻土的发育、全球变化和生态环境变迁的重要信息.全球变暖背景下,冻土区微生物对有机碳和温室气体的束缚、吸收、运移和最终排放发挥着重要的作用,在全球碳氮循环和对气候系统的反馈中扮演重要角色.

As an extreme habitat, subzero temperatures, composition and availability of nutrients, and freeze-thaw processes in permafrost strongly impact the survival and physiological states, as well as metabolic processes of microorganisms. Microbes in permafrost have successfully adapted to cryogenic stress in morphologic, physiological and biochemical levels. Freeze-thaw processes exert both a direct stress to cells, and indirect restriction to the microbial environment. The microhabitat of microorganisms inside permafrost will be altered as the water-heat balances and dynamics of permafrost being disturbed under the influence of engineering activity. Recently, interferences of infrastructures and pollutants from oil pipeline have affected permafrost＇and organisms＂ dwelling. The fluctuations of microbial numbers and biodiversities were closely related to the epigenetic permafrost and its cryogenesis and the biogeochemical cycles, which may provide proxy records for permafrost development, global climatic and eco-environmental changes. Under a warming climate, microorganisms play important roles in the sequestration, absorption, transportation and emissions of organic carbon and greenhouse gases to the atmosphere in permafrost regions.