U.S. GEOTRACES North Atlantic Sector: The Fractional Solubility of Aerosol Iron in Seawater

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。铁在许多海洋区域作为限制性营养物质的作用已经确立，大气沉积已被认为是全球海洋铁的主要来源。铁在大气沉积后溶解在海水中的部分被认为是浮游植物可利用的，因此不仅是铁的海洋地球化学循环的重要参数，而且也是全球碳循环的重要参数。我们估计这个参数仍然是不确定的，控制气溶胶Fe溶解在海水中的过程知之甚少。美国GEOTRACES北大西洋部分巡航将调查一个盆地中痕量金属和同位素的分布情况，该盆地受大气沉积的影响更大。 在这个项目中，阿拉斯加大学费尔班克斯分校的研究人员将参加这次考察，收集并缓慢地用大量的环境表层海水（和其他沥滤溶液）沥滤环境气溶胶（和源材料），以确定气溶胶铁（Fe）在北大西洋的溶解度范围，并深入了解导致这种变化的过程。这项工作将涉及GEOTRACES的指导性使命：“查明控制海洋中关键微量元素和同位素分布的过程和量化通量，并确定这些分布对环境条件变化的敏感性”。铁是GEOTRACES计划中的关键微量元素，拟议的研究将使用一种新的场方法研究气溶胶Fe的溶解度。结果将提高我们的理解如何气溶胶沉积影响铁在北大西洋的表面分布。从这项工作中获得的信息也将有助于确定如何改变环境条件（例如，增加的粉尘通量）可能影响Fe的分布和形态。更广泛的影响：将生成有关海水中铁溶解的基本信息，并将其纳入GEOTRACES数据库。该项目将提供一种独特的方法，用于研究气溶胶Fe在海水中的溶解度，这将为全球碳循环和气候变化模型提供重要信息，其中包括Fe的大气供应。 此外，它将支持阿拉斯加大学费尔班克斯（UAF）的一名职业生涯早期的女性首席研究员，并将帮助建立UAF的研究基础设施。 UAF的一名本科生将获得这项研究的支持。从这项研究中获得的信息将纳入网上传播和公共宣传活动的材料。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The role of iron as a limiting nutrient in many oceanic regions has been established, and atmospheric deposition has been recognized as a major source of iron in the global ocean. The fraction of iron that dissolves in seawater after its atmospheric deposition is thought to be available to phytoplankton, and thus an important parameter not only for the marine biogeochemical cycle of iron, but also for the global carbon cycle. Our estimate of this parameter is still uncertain, and the processes that control aerosol Fe dissolution in seawater are poorly understood. The US GEOTRACES North Atlantic Section cruise will survey the distribution of trace metals and isotopes in a basin where there is an enhanced influence from atmospheric deposition. In this project, researchers at the University of Alaska at Fairbanks will participate in this expedition to collect and slowly leach ambient aerosols (and source materials) with large volumes of ambient surface seawater (and with other leaching solutions) in order to determine the range of fractional solubility of aerosol iron (Fe) in the North Atlantic, and to provide insight into the processes that cause this variability. This work will address the guiding mission of GEOTRACES: "to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions". Iron is a key trace element in the GEOTRACES program, and the proposed study will investigate the fractional solubility of aerosol Fe using a novel field approach. Results will improve our understanding of how aerosol deposition affects the surface distribution of Fe in the North Atlantic. Information obtained from this work will also help establish how changing environmental conditions (e.g., increased dust flux) may affect the distribution and speciation of Fe. Broader Impacts: Essential information concerning the dissolution of Fe in seawater will be generated and incorporated into the GEOTRACES database. This project will provide a unique approach for investigating the fractional solubility of aerosol Fe in seawater that will result in important information for models of global carbon cycling and climate change that incorporate the aeolean supply of Fe. Additionally, it will support an early-career, female principal investigator at the University of Alaska Fairbanks (UAF), and will help build research infrastructure at UAF. An undergraduate student at UAF will receive support from this study. Information gained from this research will be incorporated into materials for web dissemination and public outreach events.