Dissolved Organic Matter Composition in the Deep Atlantic Ocean

深海溶解有机物（DOM）的转化对全球碳循环具有深远的影响，因为它可以将二氧化碳（CO2）从大气中封存起来。 虽然对这种物质的高分子量成分进行了研究，但对低分子量DOM却不能这样说，因为还没有必要的分析技术来确定其组成和反应性。 近年来，伍兹霍尔海洋研究所的一个研究小组已经获得了必要的分析能力。因此，在该项目中，他们将在西大西洋进行第一次深海DOM系统调查，以表征向南流动的北大西洋深层水（NADW），向北流动的南极底层水（AABW）和南极中层水（AAIW）中DOM的低分子量部分。 使用高分辨率质谱和多级裂解耦合液相色谱，科学家们将确定DOM组成的空间变异性沿着水流路径，以及评估源水，运输和表面过程，有助于DOM组成的时间变化。 这些结果将得到加强与结构解析和定量分析的独特的标志化合物为每个水团。 研究结果将提供重要的见解，在深海中的DOM动力学的地球化学反应。该提案中更广泛的影响部分得到了很好的发展。 除了支持和培训一名研究生外，作为他们推广工作的一部分，支持者计划为研究生和博士后开发和教授一门关于高分辨质谱的新课程。 这门课将为他们提供实践经验，并教他们在各种质谱仪上运行样品。 此外，支持者计划建立一个基金，培训学生和博士后使用多元统计工具进行数据处理和解释。

Transformations of dissolved organic matter (DOM) in the deep ocean have profound impacts on the global carbon cycle due to the sequestration of carbon dioxide (CO2) away from the atmosphere. Although research has been conducted on the high molecular weight component of this material, the same cannot be said for low molecular weight DOM because the needed analytical techniques have not been available to determine its composition and reactivity. In recent years, a research team at Woods Hole Oceanographic Institution has acquired the necessary analytical capability. As such, in this project, they will carry out the first systematic survey of deep ocean DOM in the western Atlantic Ocean to characterize the low molecular weight fraction of DOM in southward flowing North Atlantic Deep Water (NADW), northward flowing Antarctic Bottom Water (AABW), and Antarctic Intermediate Water (AAIW). Using ultrahigh resolution mass spectrometry and multi-stage fragmentation coupled to liquid chromatography, the scientists will determine the spatial variability in the composition of DOM along the flow path of the water masses, as well as assess the source water, transport, and surface processes that contribute to temporal changes in DOM composition. These results will be augmented with structural elucidation and quantitative assays of unique marker compounds for each water mass. Results will provide important insights into the biogeochemical reactions that govern DOM dynamics in the deep ocean. The broader impacts component of the proposal was well developed. Besides supporting and training one graduate student, as part of their outreach efforts, the proponents plan to develop and teach a new class on ultrahigh resolution mass spectrometry for graduate students and postdocs. This class would provide them with hands-on experience and teach them to run samples on various mass spectrometers. In addition, the proponents plan to create a fund to train students and postdocs on the use of multivariate statistical tools for data processing and interpretation.