完全氨氧化菌(又称全程硝化菌)是近年来新发现的能够独自催化氨氧化和亚硝氮氧化的微生物，其发现极大的改观了对硝化作用以往的认识。河口潮滩湿地是重要的自然生态系统类型，但是目前有关河口潮滩湿地环境中完全氨氧化菌的菌群结构、丰度和活性还缺乏深入系统的研究。为此，本项目选取长江口潮滩湿地作为典型研究区，综合运用分子生物学和同位素示踪技术，研究河口潮滩湿地内完全氨氧化菌的菌群动态变化特征；揭示完全氨氧化菌对硝化过程的贡献；并探讨其相关的氧化亚氮产生机理；以期深化对河口潮滩湿地氮循环过程的理论认识。

Complete ammonia oxidizers (Comammox, also known as complete nitrifiers) were recently discovered microorganisms which can as single organisms catalyze both ammonia oxidation and nitrite oxidation. The discovery of Comammox has fundamentally changed our view of nitrification. Estuary wetlands are important natural ecosystems; however, there are so far no detailed studies conducted on community structure, abundance and activity of Comammox in this type of environment. Therefore, the objectives of this project are by utilizing combined molecular biology and isotopic tracer techniques to study dynamics of Comammox in the intertidal sediments of the Yangtze Estuary; to estimate the contribution of Comammox to nitrification; to reveal the mechanism of associated nitrous oxide production and so as to have a better understanding of the processes of nitrogen cycle in estuary wetlands.