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

GEOTRACES是一个研究全球海洋微量元素及其同位素地球化学循环的国际计划。其指导使命是“查明控制海洋中关键微量元素和同位素分布的过程并量化通量”（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来源和/或汇，因此颗粒TEI是GEOTRACES的关键参数。事实上，海洋中粒子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）过去变化的代理发展。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大西洋剖面上收集高质量的痕量金属清洁粒度分级颗粒，并分析关键痕量元素和主要颗粒相。 他们将分析通过电池操作的原位过滤收集的粒度分级颗粒，用于科学计划中列出的所有关键微量元素（Fe，Al，Zn，Mn，Cd，Cu），一套其他感兴趣的微量元素（例如Co，Ti，Ba）和主要载体相（例如CaCO 3，生物Si和POC）。已为大西洋GEOTRACES部分提供资金，用于对短寿命放射性核素进行电池操作的现场过滤（McLane泵）。 该项目将与短寿命放射性核素小组密切协调，改造McLane泵，以便同时对粒度分级颗粒进行采样，用于痕量金属分析和放射性核素收集。更广泛的影响：由于这将是第一个完整的海洋深度分区截面的大小分级颗粒，其结果应该是一个新的和全面的了解的分布，组成和动态的颗粒，控制大部分的化学分布，碳吸收，和海洋的生物生产力。由于颗粒在影响TEI循环的许多过程中的重要性，该数据集将与GEOTRACES大西洋部分测量的其他参数结合使用。许多尚未提出的科学问题将从这一前所未有的数据集中出现，这将通过出版物和电子方式通过伍兹霍尔的BCO-DMO数据办公室提供，以便将来社区中任何人都可以探索有关颗粒分布和组成的问题。一名暑期本科生将帮助进行一些样本分析，一名麻省理工学院-世界卫生组织海洋学联合项目的研究生也将帮助进行分析。

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.