甲烷是一种重要的温室气体，对全球气候变化有重要作用，生物氧化是甲烷净消耗过程，在河口区的甲烷消耗中有重要作用。然而相对于土壤、湿地、甲烷水合物区等区域，对河口区甲烷氧化生物过程的具体机制及其与环境因素变化之间关系的认识非常有限。珠江口受人类活动影响明显，是亚热带大型河口的一种代表，该项目以理化参数变化明显的珠江口区域为研究对象，采用宏基因组技术及定量PCR技术，对甲烷氧化微生物的丰度、群落结构，甲烷氧化途径选择及关键酶基因簇变化等特征与动态环境变化之间的相互关系进行系统研究，以期了解环境变化对甲烷生物氧化这一重要生态过程的影响，进一步了解微生物代谢在亚热带河口以及全球气候变化中的重要作用。

Methanotrophs (aerobic and anaerobic) play key roles in the global carbon cycle, including controlling anthropogenic and natural emissions of CH4, the second-most important greenhouse gas after carbon dioxide. They are widespread in nature including the estuary. However, Comparing with massive investigations of methanotrophs in wetland, rice soil and marine methane-seep environments, relatively fewer studies have been conducted in estuarine environments where the geochemical profiles are much more complicated. Here, metagenomics is used to characterize the taxonomic and metabolic potential for both aerobic and anaerobic methane oxidation in the water column and sediment of Pearl River estuary. It will offer further information about how methanotrophs respond to varying environmental conditions resulting from seasonal fluctuations or longer-term climate changes.