一氧化氮（nitric oxide, NO）是大气中一种对全球气候变化和环境有重要影响的污染物质，也是生命领域广泛存在的生物体重要的生长调节因子和信号因子，同时也是海洋氮循环的一个重要中间体。然而NO在海洋生态系统的产生及影响机制研究目前尚属空白。本项目拟以长江口及其邻近海域为主要研究海区，通过实验室和现场观测，对光降解过程、硝化与反硝化过程、浮游植物生长过程中NO的生成速率开展研究，探讨它们的时空变化特征及与环境影响因素之间的关系。本项目将明确海水中NO的主要产生过程及主控因子，并探讨其释放机制。评估海洋生态系释放NO对氮循环和大气的贡献，为深入研究NO释放对区域气候和生态环境的影响奠定基础，也有助于进一步了解NO在海洋生态系中的作用与地位。

Nitric oxide (NO) is an important pollution gas in the atmosphere, which plays significant roles in the global climate changes and environment. It widely exists in the field of life, which acting as an important growth regulation factor or signal factor for organisms. It is an important intermediate of marine nitrogen cycle. However, the study is lacking about the emission of NO and influencing mechanism from marine ecosystem. In order to study the production rates of NO from photodegradation process, nitrification and denitrification process and phytoplankton growth process, experiments of laboratory simulation and culture and field observations will be conducted using the Changjiang (Yangtze) Estuary and its adjacent sea area as the main study region. The spatio-temporal variations of NO production rates in the ocean and their relationship with different environmental factors will be discussed. The aim of this study will elaborate the main process of NO production and the major controlling factor, explore their releasing mechanism, and evaluate the contribution of NO released from marine ecosystem to the nitrogen cycle and the atmosphere. These results may have implications for further research on NO release effect on regional climate and ecological environment, and will be conducive to further understand the function and role of NO in marine ecosystem.