Reassessment of dissolved DMSP concentrations and turnover flux in the ocean

“这项奖励是根据2009年美国复苏和再投资法案（公法111-5）资助的。”南阿拉巴马大学的研究人员将评估测量二甲基磺酰丙酸（DMSPd）生物可用库及其在各种海洋系统中的周转率的新方法。DMSPd在上层海洋中迅速循环，被认为是微生物群落碳和硫的来源。此外，它被认为是DMS的主要前体，DMS是一种挥发性硫化合物，参与大气硫循环，DMS是一种气候活性气体。然而，基于先前研究得出的关于DMSPd循环某些组分的结论可能是错误的，因为对其溶解浓度的测定不准确。在该项目期间将开发的新信息将用于重新评估DMSPd在海洋表面碳和硫循环中的作用，并作为DMS的前兆。这项工作的第一个目标包括确定河口、沿海和海洋水域中溶解DMSP池的生物可利用部分。第二个目标将是评估现有的分析程序，以确定它是否高估了DMSPd的生物可利用部分。第三和第四个目标侧重于该化合物周转率的方法和量化，第五个目标侧重于利用该速率信息来评估DMSPd是否是海洋微生物群落碳和硫的重要来源。DMSP通过海洋系统的质量通量可能是任何一种已知化合物中最高的。然而，这些通量的知识是不确定的，这项工作将消除很多不确定性。DMSP循环引起了包括生物地球化学、生态学和大气科学在内的众多学科的科学家的兴趣。海洋-大气微量气体交换对气候反馈具有重要意义，DMS是海洋产生的气体影响大气的一个重要例子。作为这个项目的一部分，将培训一名研究生、一名本科生和一名研究技术人员，并将开展若干涉及公共宣传和教育的活动。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Researchers at the University of South Alabama will evaluate new approaches for measuring the biologically available pool of dimethylsulfoniopropionate (DMSPd) and its turnover rate in a variety of marine systems. DMSPd is rapidly cycled in the upper ocean and is thought to be a source of carbon and sulfur for microbial communities. In addition, it is believed to be a major precursor for DMS, which is a volatile sulfur compound that is involved in the atmospheric sulfur cycle and DMS is a climate-active gas. However, conclusions regarding certain components of the DMSPd cycle that are based on prior research might be in error because of inaccurate determinations of its dissolved concentration. The new information that will be developed during this project will be used to reevaluate the role of DMSPd in the carbon and sulfur cycles of the surface ocean and as a precursor of DMS. The first objective of the work includes determining the biologically available fraction of the dissolved DMSP pool in estuarine, coastal and oceanic waters. The second objective will be to assess the existing analytical procedure to determine if it overestimates the biologically available fraction of DMSPd. The third and fourth objectives focus on the methods for, and quantifying the turnover rates of, this compound, and the fifth objective is focused on utilizing this rate information to assess whether DMSPd is a significant source of carbon and sulfur for marine microbiological communities.DMSP may have some of the highest mass fluxes through the ocean system of any single known compound. However, knowledge of those fluxes is uncertain and this work will remove a lot of that uncertainty. DMSP cycling is of interest to scientists from a broad range of disciplines including biogeochemisty, ecology and atmospheric science. Oceanic-atmospheric trace gas exchange is important to the climate feedbacks, and DMS is an important example of ocean-produced gases that can influence the atmosphere. One graduate student, one undergraduate student and one research technician will be trained as part of this project, and several activities involving public outreach and education will be initiated.