中文摘要：

硝化作用（NH4＋ NO2- NO3-）是氮的生物地球化学循环的关键环节，氨氧化古菌（AOA）纯培养物和富集物的获得，以及古菌amo基因在各种生态环境中的发现，说明AOA也是氨氧化作用的贡献者；特别是很多环境中AOA amo的丰度是氨氧化细菌AOB amo的数十倍甚至上万倍，而且AOA具有比AOB更高的氨氮亲和性，这些进一步说明了氨氧化细菌（AOA）可能是氨氧化作用的主要贡献者。文中综述了AOA菌株和富集物的来源及基因组信息、基于系统发育的AOA分类、AOA氨氧化作用在环境中的重要性，以及AOA反硝化作用的发现，并对今后的研究方向进行了展望。

英文摘要：

Nitrification,namely the oxidation of ammonia to nitrite via nitrate,has been suggested to be a key part of the global biogeochemical nitrogen cycle.The cultivation of pure isolates and enrichments of ammonia-oxidizing archaea （AOA）as well as the discovery of archaeal amo gene in different kinds of environments has proved the contribution of AOA to the nitrification in the earth.Especially,the abundance of archaeal amo in most environ-ments is higher than that of bacterial amo,and the affinity of AOA to ammonia nitrogen is higher than that of AOB. All these suggest that AOA might predominately contribute to the global nitrification.This paper gives an overview of the sources and genomic information of pure AOA cultures and enrichments,the AOA taxa based on phylogenetic analysis,the importance of ammonia oxidation to the environment and the discovery of AOA denitrification.It also proposes several research prospects in the future.