US GEOTRACES North Atlantic Section: Analysis of Key Trace Elements in Size-fractionated Marine Particles

GeoTRACE是一个研究全球海洋生物地球化学循环的国际项目，其研究对象是微量元素及其同位素(TEI)。其指导使命是“确定控制海洋中关键微量元素和同位素[TEI]分布的过程和通量”(GEOTRACES科学计划，2006年)。由于海洋中的颗粒是许多微量元素和同位素的重要源和/或汇，颗粒TEI是GEOTRACES的关键参数。事实上，海洋中颗粒的组成和分布对于理解科学计划确定的所有三个主题至关重要：1)海洋界面的通量和过程，2)内部循环，以及3)过去变化的替代物的发展。在该项目中，伍兹霍尔海洋研究所的研究人员将得到支持，以确保在美国北大西洋GEOTRACES大西洋段收集高质量的痕量金属清洁分级颗粒，并分析关键痕量元素和主要颗粒物相。他们将分析电池操作的原位过滤收集的粒度分级颗粒，以确定科学计划中列出的所有关键微量元素(铁、铝、锌、锰、镉、铜)、一套其他感兴趣的微量元素(如钴、钛、钡)以及主要载体相(如碳酸钙、生物硅和POC)。使用电池进行的短效放射性核素的就地过滤(McLane泵)的运作已经为大西洋地质轨道系统科提供了资金。该项目将与短期放射性核素小组密切协调，改装McLane泵，以便同时对粒度分级的粒子进行采样，以进行痕量金属分析和放射性核素收集。更广泛的影响：由于这将是第一个全海洋深度的分级颗粒物分区，其结果应该是对控制海洋大部分化学分布、碳吸收和生物生产力的颗粒物的分布、组成和动力学有一个新的和全面的了解。由于粒子在影响TEI循环的许多过程中的重要性，该数据集与在GEOTRACES大西洋部分测量的其他参数将是无价的。这个史无前例的数据集将出现许多尚未提出的科学问题，这些数据将通过出版物和位于伍兹霍尔的BCO-DMO数据办公室以电子方式提供，以便社区中任何探索粒子分布和组成问题的人将来都可以挖掘它。一名暑期本科生将帮助进行一些样本分析，麻省理工学院-世界卫生组织海洋学联合项目的研究生也将提供帮助。

GEOTRACES is an international program to study the global marine biogeochemical cycles of trace elements and their isotopes (TEIs). Its guiding mission is to "identify processes and quantify fluxes that control the distributions of key trace elements and isotopes [TEIs] in the ocean" (GEOTRACES Science Plan, 2006). Because particles in the ocean serve as important sources and/or sinks for many trace elements and isotopes, particulate TEIs are key parameters for GEOTRACES. Indeed, the composition and distribution of particles in the ocean is crucial to understanding all three themes identified by the Science Plan: 1) Fluxes and processes at ocean interfaces, 2) Internal cycling, and 3) Development of proxies for past change. In this project, researchers at the Woods Hole Oceanographic Institution will be supported to ensure the collection of high quality trace metal clean size-fractionated particles on the US North Atlantic GEOTRACES Atlantic section and the analysis of key trace elements and major particulate phases. They will analyze size-fractionated particles collected by battery operated in-situ filtration for all key trace elements listed in the Science Plan (Fe, Al, Zn, Mn, Cd, Cu), a suite of other trace elements of interest (e.g. Co, Ti, Ba), and major carrier phases (e.g. CaCO3, biogenic Si, and POC). The operation of battery operated in-situ filtration (McLane pumps) for short-lived radionuclides is already funded for the Atlantic GEOTRACES section. This project will coordinate closely with the short-lived radionuclide group to adapt McLane pumps for simultaneous sampling of size-fractionated particles for trace metal analysis and radionuclide collection. Broader Impacts: Inasmuch as this will be the first full ocean depth zonal section of size-fractionated particulates, the result should be a novel and comprehensive understanding of the distribution, composition, and dynamics of the particles that control much of the chemical distribution, carbon uptake, and the biological productivity of the ocean. Because of the importance of particles in so many processes affecting the cycling of TEIs, this dataset will be invaluable in conjunction with other parameters measured on the GEOTRACES Atlantic section. Many as yet unposed scientific questions will emerge from this unprecedented dataset, which will be made available through publication and electronically through the BCO-DMO data office at Woods Hole so that it can be mined in the future by anyone in the community exploring questions about particle distribution and composition. A summer undergraduate student will help with some sample analyses, as will a graduate student in the MIT-WHOI Joint Program in Oceanography.