稳定同位素技术研究湿地甲烷产生的微生物过程进展

湿地甲烷排放对于全球大气甲烷浓度起着关键作用，深入了解湿地甲烷排放的微生物过程对于构建甲烷排放的过程模型和解决全球甲烷排放清单的不确定性极为重要。本文简要介绍湿地微生物产生甲烷的基本过程，以及利用稳定同位素技术研究甲烷产生的不同途径和不同微生物种类在甲烷产生过程中的作用，并分析该领域的最新研究进展和未来研究重点。利用稳定同位素技术研究湿地环境中各种产甲烷途径贡献的难点在于醋酸产甲烷途径和CO2产甲烷途径的同位素分馏因子的确定。利用稳定同位素技术研究不同微生物种类在甲烷产生过程中的实际功能，明显优于传统的分子生物学方法，这两种技术的结合将为建立微生物的群落结构、功能结构与对应的代谢功能之间的关系提供新的研究思路。

Progresses in the Stable Isotope Studies of Microbial Processes Associated with Wetland Methane Production

Methane emissions from wetlands play a key role in regulating global atmospheric methane concentration, so better understanding of microbial processes for the methane emission in wetlands is critical for developing process models and reducing uncertainty in global methane emission inventory. In this review, we describe basic microbial processes for wetland methane production and then demonstrate how stable isotope fractionation and stable isotope probing can be used to investigate the mechanisms underlying different methanogenic pathways and to quantify microbial species envolved in wetland methane production. When applying stable isotope technique to calculate contributions of different pathways to the total methane production in various wetlands, the technical challenge is how to determine isotopic fractionation factors for the acetate derived methane production and carbon dioxide derived methane production. Although the application of stable isotope probing techniques to study the actual functions of different microbial organisms to methane production process is significantly superior to the traditional molecular biology method, the combination of these two technologies will be crucial for direct linking of the microbial community and funtional structure with the corresponding metabolics functions, and provide new ideas for future studies.