河口和海岸带区域是全球大气、陆地和海洋之间的联系纽带，储藏了大量的有机碳。这些有机碳的转化与CO2的生成使河口成为影响地球温室气体释放和碳循环的重要一环。研究发现有机质丰富的河口和海洋沉积物中含有丰富的深古菌门古菌，推测其代谢活动在河口及海洋沉积物的有机质转化中发挥了重要作用。然而深古菌是一类尚不可培养的古菌类群，具有很高的多样性和异质性（至少有21个不同的亚群），目前对其碳源利用尚缺乏直接的证据，限制了对其生态功能和意义的认识。本申请拟通过高通量测序技术研究珠江口深古菌不同亚群的时空变化特征，分析不同亚群环境选择和适应特征；并利用同位素探针标记开展富集培养，揭示深古菌的碳源利用特征，为深古菌有机质底物利用提供直接证据。本研究将为进一步认识河口区微生物介导的有机质转化机制提供数据和理论基础。

Estuary is the important link between the land and the ocean with typically high amount of terrestrial organic carbon being transported through it. Bathyarchaeota is a cosmopolitan group with high phylogenetic diversity. Its metabolism is considered to be important in the organic matter transformation of the sediment of estuary and marine. However, there are no clear indications about the physiological capabilities and the ecological roles of this widespread archaeal group due to the lack of pure cultures. In this project, the stable isotopic probing (SIP), metagenomics are used to investigate the time and spatial distribution of Bathyarchaeota in the Pearl River estuary, examine the carbon sources of Bathyarchaeota. Results of this study will provide insight about the improtant role of the Bathyarchaeota in the estuary carbon cycle.