Research progress of aerobic methane oxidation process in inland waters

Abstract

内陆水体是全球碳循环的关键组成部分，是大气中甲烷（CH₄）的重要来源，每年从内陆淡水与自然湿地排放进入大气的CH₄约为185~357 Tg/a.通常，内陆水体中CH₄主要由分布于水层底部的厌氧区或沉积层内的产甲烷菌介导产生，其向水层表面传输的过程中易被甲烷氧化菌所氧化.甲烷氧化菌可分为好氧甲烷氧化菌和厌氧甲烷氧化菌，有氧条件下，由好氧甲烷氧化菌介导的好氧甲烷氧化过程是水体中甲烷氧化过程的主要形式，湖泊底部产生的CH₄总量中约有99%可以被上覆水体中的好氧甲烷氧化过程所消耗.本文收集文献综合分析阐明，好氧甲烷氧化过程是由水环境因子、水文条件以及不同内陆水体的生态系统特征共同调控，同时也表现在了好氧甲烷氧化菌的生境偏好上.复杂的调控过程构建了内陆水体向大气输送CH₄的动态平衡，并最终反映在内陆水体对全球CH₄循环、碳循环作出的贡献上.;Inland waters are important parts in global carbon biogeochemial cycles. It is also one of the main sources of methane. Annual emissions of CH₄ from inland freshwaters and natural wetlands into the atmosphere is 185-357 Tg/a. Methane is mainly produced by the reactions between bottom organic sediments and methanogenic bacteria in anoxic zone of inland waters. Methane is then consumed by methane-oxidizing bacteria during its upsurge to surface water. Methane-oxidizing bacteria can be divided into aerobic methane-oxidizing bacteria and anaerobic methane-oxidizing bacteria. Under aerobic conditions, the aerobic methane oxidation process mediated by aerobic methane-oxidizing bacteria is the main form of methane oxidation process in water, and about 99% of the total CH₄ produced at the bottom of the lake can be consumed by the aerobic methane oxidation process in the overlying water. According to the comprehensive analysis of literature collected in this paper, the process of aerobic methane oxidation is controlled by water environmental factors, hydrological conditions and ecosystem characteristics of different inland waters, and also reflected in the habitat preference of aerobic methane-oxidizing bacteria. The complex regulation process constructs the dynamic balance of the total amount of CH₄ transported from inland waters to the atmosphere, which is reflected in the contribution of inland waters to the global CH₄ cycle and carbon cycle.