异养微生物在驱动有机碳矿化过程中发挥着关键作用，但目前绝大多数微生物类群对有机碳的降解转化过程和机制以及对有机碳矿化的贡献尚不明确，阻碍了人们对海洋碳循环的认识。本项目拟以边缘海中分布广、丰度高且异养代谢活性强的弧菌为研究对象，通过对其在我国边缘海不同环境中的丰度、种类组成和遗传多样性等方面进行研究，阐明弧菌在我国边缘海的分布规律；通过对弧菌地理分布特征和种群遗传学特征与环境因素的相关性分析，找出影响弧菌分布及其生态功能的主控因子；通过检测弧菌对不同类型有机物的降解效率，揭示其在海洋有机碳降解过程中的贡献；通过对典型有机物降解酶基因进行异源表达、降解活性及降解产物的检测，揭示弧菌对有机碳的降解机制。最后，结合弧菌生态分布等的研究结果，估算弧菌在我国边缘海碳循环中的贡献。通过以上研究，加深人们对异养微生物在边缘海碳循环中所发挥作用的认知。

Heterotrophic microorganisms are known to play key roles in driving remineralization of organic carbon. However, the degradation and transformation processes and mechanisms on organic carbon as well as the contribution to organic carbon remineralization of most microbial groups are poorly understood, which hinders our understanding of marine carbon cycle. The study object of this project is Vibrio species, a widespread bacterial species in marginal seas with high abundance and heterotrophic metabolic activities. The abundance, species composition and genetic diversity of Vibrio species in different environments of Chinese marginal seas will be investigated, and their distribution patterns in Chinese marginal seas will be determined; the correlation between geographic distribution patterns as well as population genetics properties of Vibrio species and various environmental factors will be analyzed, and the main control factors that affect the distribution and ecological roles exertion of Vibrio species will be discovered; degradation efficiencies of Vibrio species on different types of organic carbons will be tested, and the contribution of Vibrio species in degradation of marine organic carbon will be revealed; genes encoding hydrolytic enzymes to typical organic carbon will be cloned and heterologous expressed, the degradation activity will be detected and the hydrolysed product will be identified, and the degradation mechanism of Vibrio species to typical organic carbon will be revealed. Finally, all the results will be combined, and the roles of Vibrio species on carbon cycle of Chinese marginal seas will be evaluated. Based on the above studies, the knowledge of the contribution of heterotrophic microbial communities to carbon cycle in marginal seas will be enriched.