土壤微生物群落对全球气候变化响应的研究进展

Responses of soil microbial community to global climate change: a review

摘要:

全球气候变化对陆地生态系统过程和功能产生重要影响，土壤微生物群落在陆地生态系统几乎所有的生物地球化学循环过程起到关键作用。本文针对气候变化对土壤微生物的影响研究结果，主要从土壤微生物活性(土壤呼吸与酶活性)和微生物群落结构对大气CO₂升高、增温、降水变化、氮沉降等全球变化单因子和多因子的直接或间接响应进行综述，并进一步阐述参与土壤碳氮循环过程的功能微生物对气候变化的响应机制与适应规律。全球变化因子改变了土壤微生物的群落组成，呈现降低、增加和无影响3种效应，且不同功能微生物也呈现不同的敏感性。多个全球变化因子对土壤微生物群落结构的交互效应可能存在加性、协同、拮抗作用，产生加和的、相互促进或抵消的整体效果。然而，目前对多种全球变化因子如三因子或四因子的组合作用，以及多因子的高阶交互作用研究较少；已有的研究地理分布不均匀，且时间和空间大尺度的研究不足；缺乏综合生态系统模型对全球变化的影响进行模拟和预测。最后指出今后的研究发展方向：进行多种全球变化因子、长时间、多生态系统点位、大空间尺度的土壤微生物群落动态研究；探究多种全球变化因子的高阶交互作用；建立综合响应的生态系统模型，精确全球气候变化及其交互作用对土壤微生物群落影响的估算。这将有助于准确预测未来全球气候变化情景下生态系统尤其是土壤微生物生态系统的响应，为生态系统的可持续发展提供科学基础。

关键词:土壤微生物群落;气候变化;增温;大气CO₂浓度升高;氮沉降;降水变化;交互作用

Abstract:

Global climate change affects the processes and functions of terrestrial ecosystems where soil microbial community plays a crucial role in almost all of the biogeochemical cycles. Here, we reviewed the direct and indirect responses of soil microbial activities (e.g., soil respiration and enzyme activities) and community structure to individual and multiple global change factors, including elevated CO₂ concentration, warming, altered precipitation, and nitrogen deposition. Besides, we summarized the mechanisms for the adaptation of soil microbial community and the responses of functional microorganisms involved in soil carbon and nitrogen cycle to climate change. Generally, these global change factors may have positive, negative, or insignificant effects on soil microbial communities, and different functional microorganisms also showed different sensitivity to them. Moreover, the interactive effect of multiple global change factors on soil microbial community structure may be additive, synergistic, or antagonistic. However, there is a paucity of research on the combined effects of multiple global change factors, such as three, four, and even more factors. In addition, the distribution of the studied areas is uneven, and studies involving various ecosystems with large spatial and temporal scale are scarce. No comprehensive ecosystem model is available to simulate and predict the effects of global change on soil microbial communities. Finally, we summarized the research trends: (1) dynamic monitoring of soil microbial communities in multiple ecosystems in large spatial scale for a long time involving multiple global change factors, (2) the interaction of multiple global change factors, and (3) development of comprehensive ecosystem model to accurately estimate the impact of global climate change and factors’ interaction on soil microbial community. These will help to accurately predict the response of ecosystem, especially soil microbial ecosystems, under future global climate change scenarios, and lay a basis for the sustainable development of ecosystems.

Key words:soil microbial community;climate change;warming;elevated CO₂ concentration;N deposition;altered precipitation;interaction