Marine Biogeochemistry of Dissolved DMSP and its Sulfur Containing Degradation Products

9530378基恩，这项为期三年的研究将增进我们对溶解的二甲基磺胺在表层海水中硫还原的生物地球化学中所发挥的作用的基本了解。该项目的具体目标是：1)测试用常规过滤技术测量的溶解的DMSP池是否真正溶解；2)测量使用14C和35S DMSP的天然微生物组合对溶解的DMSP的吸收动力学，并确定DMSP的就地周转率；3)测量DMSP降解过程中形成的硫产物和确定不同水域中裂解酶(形成二甲基硫醇)和去甲硫醇(形成甲硫醇)途径之间的分支比率；4)确定好氧海水中甲烷硫醇的产生机制，最后确定网目在海水中的损失动力学及其影响因素。这项工作将主要使用墨西哥湾北部的沿海和陆架水样进行，但计划进行两次海洋巡航，以提供来自温暖的少营养和冷的中营养海洋水域的补充信息。由此产生的数据应该会极大地提高我们对DMSP在海洋中是如何处理的，以及它如何通过产生DMS和甲硫醇等重要的还原硫化合物来影响地表水化学的知识。

9530378 Kiene This three year study will increase our fundamental understanding of the role played by dissolved DMSP in the biogeochemistry of reduced sulfur in surface seawater. The specific objectives of the project are 1) to test whether the dissolved DMSP pool measured by conventional filtration techniques is truly dissolved; 2) to measure the kinetics of uptake for dissolved DMSP by natural microbial assemblages using 14C and 35S DMSP and to determine in situ turnover rates for DMSP (d); 3) to measure the sulfur products formed during DMSP degradation and to determine how the branching ratio between the lyase (DMS forming) and demethylation (methanethiol forming) pathways vary in different waters; 4) to determine mechanisms of methanethiol production in aerobic seawater and finally, to determine the loss kinetics of MeSH in seawater and the factors which affect these. The work will be carried out using primarily coastal and shelf water samples from the Northern Gulf of Mexico, but 2 oceanographic cruises are planned to provide complementary information from warm oligotrophic and cool mesotrophic ocean waters. The resulting data should greatly advance our knowledge of how DMSP is processed in the sea and how it impacts the chemistry of surface waters through production of important reduced sulfur compounds like DMS and methanethiol.