环境变化对森林土壤CH_4氧化的影响

Effects of Environmental Change on the Oxidation of Methane in Forest Soils

甲烷(CH4)是一种重要的温室气体,对全球气候变暖的贡献仅次于CO2,而环境的变化将影响森林土壤CH4的氧化能力从而改变全球CH4平衡.森林土壤CH4氧化对全球变暖的敏感性较低;降雨量增加、大气CO2浓度升高、森林皆伐及森林转变为农业用地导致森林土壤CH4氧化能力下降,而降雨量减少、大气CH4浓度上升、农业用地转变为森林,土壤CH4氧化能力提高;森林间伐、火烧及无机N的输入对森林土壤CH4氧化的影响表现为抑制、促进和无影响3种模式.环境变化对森林土壤CH4氧化影响因素及机理等方面已进行较深入的研究,本研究对此进行归纳总结,并提出以下几个未来研究的着重点:长期的定位观测;采用多因子交互作用的研究方法,获得各因子交互作用对森林土壤CH4氧化能力的影响;深化甲烷氧化菌与产甲烷菌对环境变化响应机理的研究;从机理上区分非铵盐的抑制作用与酶基质的竞争作用;关注森林管理措施(林分皆伐、间伐、火烧)对土壤CH4氧化的影响,探讨哪些恢复措施能加快土壤CH4氧化能力的恢复.

Being second only to CO2,CH4 is one of important greenhouse gases contributing to global warming.The capability for forest soils to oxidize methane is likely affected by environmental change,which may impose an impact on global CH4 balance.The sensitivity of methane oxidation to global warming is low,whereas CH4 oxidation rate can be tremendously reduced with the increasing of precipitation and atmospheric CO2 concentration in forest soils,and with clear cutting or converting into agricultural lands.In the other way around,the oxidation rate increases.Forest thinning and burning,N inputs,including N fertilizer and atmospheric N deposition,affect CH4 oxidation capacity in various forms.Although intensive researches have ever been done in last decade,uncertainties of CH4 oxidation in forest ecosystems still remain.Further study should focus on： long-term in situ observation;using factors of interaction methods to obtain the effects of capability for forest soils to oxidize methane;researching into the mechanism of methanotroph and methanogen responding to environmental change;distinguishing between the non-ammonium salt inhibitory and enzyme matrix competition;assessing management activities（forest clear cutting,thinning and burning）on CH4 oxidation;and,the study of restoration measures which can promote CH4 oxidation capability.