Marine Geochemistry of Dimethylsulfide

拟议的研究将调查地球化学 二甲基硫（DMS）在海水中的循环。 海洋是一个 全球生物源还原硫的主要来源 大气中，水平大致相当于人为SO2 排放 二甲基硫占海洋生物源的90%左右， 硫通量 本次调查的目的是 阐明参与的速率，途径和过程 DMS在海洋中的形成、转化和消耗。 这些地球化学信息对于了解 DMS浓度分布图，已观察到在 这可能会影响未来的抽样策略。 一个a 更大的规模，更全面地了解海洋 二甲基硫醚的地球化学及其作用过程 在海水中循环将有助于确定 海洋生物地球化学过程和 挥发性生物硫化合物起主要作用 在全球大气硫循环中。 将讨论四个工作假设：1）退化 海藻二甲基磺基丙酸酯（DMSP，DMS前体） DMS的释放是正常代谢过程的结果 DMS的释放是由于浮游植物的生理活动 对浮游植物的胁迫作用; 3）DMSF的微生物降解- 含藻类物质的海水是二甲基硫醚的来源; 4） 微生物降解是二甲基硫在海水中的汇。 的 评估这些假设的方法将结合联合收割机实验室 和田间孵化实验。 实验室研究将 在受控环境条件下进行， 选择的单独和混合培养的藻类和细菌 物种 将改变实验条件以检查 在DMS循环中可能很重要的特定因素。 领域 研究将被用来检查下的过程， 自然条件。

The proposed research will investigate the biogeochemical cycle of dimethylsulfide (DMS) in seawater. The ocean is a major source of biogenic reduced sulfur to the global atmosphere, at a level roughly equivalent to anthropogenic SO2 emissions. DMS accounts for some 90% of the marine biogenic sulfur flux. The objective of this investigation is to elucidate the rates, pathways, and processes involved in the formation, transformation, and consumption of DMS in the ocean. This biogeochemical information is vital to understanding the DMS concentration profiles which have been observed in the field and may influence future sampling strategies. One a larger scale, a fuller understanding of the marine biogeochemistry of DMS and the processes involved in DMS cycling in seawater will aid in defining the relationship between oceanic biogeochemical processes and the production of the volatile biogenic sulfur compound which plays a major role in the global atmospheric sulfur cycle. Four working hypotheses will be addressed: 1) Degradation of algal dimethylsulfoniopropionate (DMSP, the DMS precursor) and release of DMS is the result of normal metabolic processes by phytoplankton; 2) release of DMS results form physiological stress on the phytoplankton; 3) microbial degradation of DMSF- containing algal material is a source of DMS in seawater; 4) microbial degradation is a sink of DMS in seawater. The approach to assessing these hypotheses will combine laboratory and field incubation experiments. Laboratory studies will be conducted under controlled environmental conditions and using selected individual and mixed culture algal and bacterial species. Experimental conditions will be varied to examine specific factors which may be important in DMS cycling. Field studies will then be used to examine the processes under natural conditions.