作为海洋具有重要气候意义的生源活性气体二甲基硫（DMS）的主要前体物质、海洋浮游植物和微生物生长重要的硫源和碳源，DMSP研究是目前国际海洋科学研究的前沿领域。本项目将聚焦于全球气候变化响应和反馈最敏感的白令海和西北冰洋，以海水DMSP时空格局和生物周转为研究核心，具体测定白令海、楚科奇海、加拿大海盆海水DMSP浓度、生产和降解速率，重点研究白令海、楚科奇海、加拿大海盆海水DMSP浓度的时空变化特征及关键生产降解过程，认清DMSP分布、生产和周转的区域差异性和特殊性，识别DMSP主要生产者和降解者，定量确定DMSP对浮游植物和细菌碳硫源的贡献，筛选影响DMSP浓度时空变化格局和生产降解的调控因素，揭示北极海域在海洋生源硫的生物地球化学循环中的独特性和敏感性，对全球DMSP生产周转过程提供创新性认识，为深入研究北极海域对区域和全球生态效应、气候变化的响应提供科学依据。

Oceanic dimethylsulfoniopropionate (DMSP) is rapidly cycled and is thought to be a major source of carbon and sulfur for phytoplankton and microbial communities and a major precursor of the climate active gas DMS. DMSP cycling is therefore of considerable interest to the international scientists from broad range of disciplines including biogeochemistry, ecology and atmospheric science. In this project, we will study the spatio-temporal dynamics, production and turnover of DMSP in the Bering Sea and western Arctic Ocean which play a critical role in both past and present global climate change. We will use a novel isotope tracer method to quantify the in-situ turnover rates of DMSP and its related compounds (DMS) in the Bering Sea, Chukchi Sea and Canada Basin, and to investigate temporal evolution of cycling rates and the biochemical factors which control the fate of sulfur from DMSP in the Bering Sea and western Arctic Ocean. Results from this study will provide unique data to determine how the branching ratios between the lyase and demethylation pathways vary in different currents of the investigation areas, to identify the main production and degradation contributors of DMSP, and to quantify the contribution of DMSP to bacterial/phytoplankton carbon and sulfur demands in the Bering Sea and western Arctic Ocean. The resulting data will greatly advance our knowledge of how DMSP is processed in the study area, how it impacts the chemistry of surface waters through the production of important reduced sulfur compounds DMS, and how global warming and rapid sea ice retreat affects the Arctic DMSP sink and source, with a focus on biological and physical processes in the Arctic Ocean.