森林土壤氧化（吸收）甲烷研究进展

甲烷是一种重要的温室气体,对全球气候变暖的贡献仅次于CO2,约为25%。大气甲烷可以被土壤中甲烷氧化细菌在有氧条件下吸收利用,陆地生态系统森林土壤氧化吸收甲烷的研究已有大量报道。甲烷氧化菌是以甲烷作为唯一的碳源和能源的一类细菌的总称。但森林土壤在全球甲烷核算中具有一定的不确定性,取决于产甲烷菌和甲烷氧化菌的相对活性。甲烷氧化菌的研究集中在环境对氧化能力的影响和自身氧化能力上。大气甲烷氧化过程为高氧化能力低亲力氧化,受到一些因子,如土壤温度、土壤通气状况、pH、氮肥等的影响,具体机理的研究还有待进一步深入。土壤通气状况受土壤质地与土壤水分影响,土地利用类型可能改变土壤容重、土壤结构和土壤水分,进而影响土壤甲烷氧化。植物可以通过自身对生境的作用或化感作用影响土壤甲烷氧化。土壤动物的研究则相对较少,目前排放清单中仅有白蚁是全球甲烷核算所包括的。从甲烷氧化菌的分类出发,对甲烷氧化菌氧化甲烷的机理、菌的生态分布及甲烷氧化的影响因素、时空异质性、观测方法等作出了综述,为正确认识和准确预测森林土壤在一定气候和土地利用类型条件下的甲烷氧化强度提供理论依据。

Advances in the research of methane oxidation in forest soils

Methane（CH4） is an important greenhouse gas,which is second only to carbon dioxide and about 25% contribution to global warming.Atmospheric methane can be oxidized by methanotrophic bacteria under aerobic condition.There are numerous reports of atmospheric CH4 oxidation and absorption in forest soils.Methanotrophic bacteria are a group of bacteria physiologically defined by their ability to use methane as sole source of carbon and energy for growth.However,it remains considerable uncertainty about the amounts of CH4 released from forest soils to the atmosphere,which depended on the abundance and relative activity of methanogenus and methanotrophic bacteria in forest ecosystems.Most studies have been focused on the environmental effects on the oxidizability and the biochemical properties of methanotrophic bacteria.The oxidation processes were a kind of high capacity and low affinity oxidation,affected by lots of factors,such as soil temperature,soil aeration,soil pH and nitrogen fertilizer.Generally,soil aeration was influenced by soil texture and soil moisture.And soil bulk density,soil structure and moisture were also influenced by land use types,and thereby affecting soil methane oxidation.Soil methane oxidation capacity also could be influenced by plants through changes in habitat or allelopathy.Few studies on soil animals,only termites in the emissions inventory is included in the global methane accounting.Starting from the classification of the methane-oxidizing bacteria,the methanotrophs on methane oxidation mechanism,the ecological distribution of the bacteria and methane oxidation factors,spatial and temporal heterogeneity,observation methods are reviewed.So,this review could provide a theoretical basis to correctly understand and accurately predict forest soil methane oxidation under the conditions of a certain type of climate and land use intensity.