大气氮沉降对森林土壤甲烷吸收和氧化亚氮排放的影响及其微生物学机制  

Microbial mechanisms responsible for the effects of atmospheric nitrogen deposition on methane uptake and nitrous oxide emission in forest soils: a review

作　　者：方华军[1] 程淑兰[2] 于贵瑞[1] 王永生[1] 徐敏杰[2] 党旭升[1] 李林森[2] 王磊[1] 

机构地区：[1]中国科学院地理科学与资源研究所/生态系统观测与模拟重点实验室,北京100101 [2]中国科学院大学,北京100049

出　　处：《生态学报》2014年第17期4799-4806,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金(31290222;31290221;31130009;31070435;41071166);国家重点基础研究发展计划项目(2012CB417103;2010CB833502);中国科学院地理科学与资源研究所"秉维"优秀青年人才基金(2011RC202);中国科学院战略性先导科技专项(XDA05050600)

摘　　要：水分非饱和的森林土壤是大气甲烷(CH4)汇和氧化亚氮(N2O)源,大气氮沉降增加是导致森林土壤碳氮气体通量不平衡的主要原因之一。土壤CH4吸收和N2O排放之间存在协同、消长和随机等复杂的耦合关系,关于氮素对两者产生过程的调节作用以及内在的微生物学机制至今尚不完全清楚。综述了森林土壤CH4吸收和N2O排放耦合过程的理论基础,土壤CH4和N2O的产生与消耗过程对增氮响应的生物化学和微生物学机制,指出各研究领域的不足和未来的研究重点。总体而言,低氮倾向于促进贫氮森林土壤CH4吸收,不改变土壤N2O的排放,而高氮显著抑制富氮森林土壤CH4吸收以及促进N2O排放。外源性氮素通过竞争抑制和毒性抑制来调控森林土壤CH4的吸收,而通过促进土壤硝化和反硝化过程来增加N2O的排放。然而,由于全球氮沉降控制试验网络分布的不均匀性、土壤碳氮通量产生过程的复杂性以及微生物分子生态学方法的局限性等原因,导致氮素对森林土壤碳氮通量的调控机制研究一直进展缓慢,未能将微生物功能群落动态与土壤碳氮通量真正地联系起来。未来研究应该从流域、生态系统和分子尺度上深入探讨土壤碳氮通量耦合作用的环境驱动机制,氮素对土壤CH4氧化和N2O产生过程的调控作用,以及增氮对土壤甲烷氧化菌和N2O产生菌活性和群落组成的影响。The well-aerated forest soils are an important sink and source of atmospheric methane （ CH4） and nitrous oxide sinks （N2O） , respectively. The increase in atmospheric nitrogen deposition is the main reasons for explaning the imbalance of carbon and nitrogen gas fluxes from forest soils. The coupling between soil CH4uptake and N2O emission is complex including synergism, antagonism and radom, and the microbial mechanisms responsible for the regulation of soil available nitrogen to their interaction has not fully understood. In this paper, we reviewed the theoretical foundation of CH4 uptake and N2O emission coupling in forest soils, and the biochemical and microibal mechanisms involved in the effects N addition on soil CH4 and N2O production and consumption. Overall, the low level of nitrogen addition tends to promote soil CH4 uptake and does not change soil N2O emission in the N-poor forests; however, high level of N addition will significantly inhibite soil CH4 uptake and promote soil N2O emission in the N-rich forests. Exogenous N inputs regulate forest soil CH4 uptake through the competitive inhibition and toxic inhibition, and increase soil N2O emission through promoting soil nitrification and denitrification processes. Because of the uneven distribution of the N deposition manupulative experiment sites, the complex generation and comsuption of soil carbon and nitrogen fluxes, and the limitations of molecular biological techniques, the internal mechanisms responsible for the regulation of nitrogen to the interaction and coupling of forest soil carbon and nitrogen fluxes has not been clarified so far; moreover, the relationships between soil functional microbial communities and soil carbon and nitrogen dynamics has not linked. Future research should focus on the following aspects： （1） at the watershed scale, the driving mechanism of environmental factors to the coupling of soil carbon and nitrogen fluxes should be examined; （2） at the ecosystem scale, the regulation of N addition levels and f

关 键 词：大气氮沉降 甲烷吸收 氧化亚氮排放 耦合作用 分子生物学 

分 类 号：S714[农业科学—林学]