US GEOTRACES GP17-ANT: Quantifying the Properties of Atmospheric Trace Elements and Their Fluxes to the Amundsen Sea

国际GEOTRACES计划的目标是了解许多化学元素及其同位素在海洋中的分布。美国国家科学基金会正在支持美国GEOTRACES在南大洋和阿蒙森海的取样考察。作为美国GEOTRACES GP17-ANT部分的一部分，这个为期三年的项目首次测量了微量元素的大气特性及其到阿蒙森海的通量。该项目将侧重于大气气溶胶中微量元素的测量，大气气溶胶是海洋许多地区微量元素的重要来源。此外，调查人员还将确定灰尘和气溶胶颗粒的来源，并量化输送到海洋表面的微量金属的数量，这些金属为浮游植物的大量繁殖提供了必需的营养。该项目的新观测数据可用于支持大气和海洋模式对耦合海气相互作用的模拟和预估，促进跨学科科学的发展。该项目将通过让女性和少数民族学生参与博士和本科阶段的研究，产生重大而广泛的影响。首席研究员将把这个项目的结果融入到她的教学中，用现实世界的研究实例来促进课堂学习，她将积极参与GEOTRACES的外展计划，为其教育活动做出贡献。该项目的主要目标是量化大气微量元素的关键特性及其对阿蒙森海的通量。最终目标是促进对大气-海洋-冰相互作用的认识，以提高对地球气候系统的了解。本项目的工作目标是：(1)确定气溶胶组成和矿物学，探索粉尘来源和目标微量元素，包括Fe、Al、Ca、Cd、Co、Cu、K、Mn、Na Ni、P、Pb、Ti、V、Zn；(2)测量气溶胶微量元素的粒径分布、气溶胶Fe的溶解度和形态、草酸盐和铵等有机/无机配体以及甲烷磺酸盐和非海盐硫酸盐等海洋生物示踪剂，更好地了解微量元素的溶解度及其影响过程；(3)定量测定干沉降和湿沉降过程中大气中微量元素的总通量，有助于了解海水中微量元素的分布。GP17-ANT巡航收集的气溶胶样本将通过电感耦合等离子体质谱（ICPMS）、基于同步加速器的x射线吸收光谱（XAS）和扫描电子显微镜（SEM）分析浓度、成分和矿物学。将对影响研究区域的不同气团省份进行基于气团反轨迹的聚类分析。气溶胶样品中的铁溶解度和形态将使用UV/VIS分光光度法和基于同步加速器的XAS进行测量。离子色谱法将用于确定水溶性有机和无机物种的海洋来源。将测量大小分离的气溶胶和降水中的微量元素。大气沉积模式将用于计算阿蒙森海的沉积通量。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The goal of the international GEOTRACES program is to understand the distributions of many chemical elements and their isotopes in the oceans. The National Science Foundation is supporting a U.S. GEOTRACES sampling expedition in the Southern Ocean and Amundsen Sea. This three-year project, for the first time, measures the atmospheric properties of trace elements and their fluxes to the Amundsen Sea as part of the US GEOTRACES GP17-ANT section. This project will focus on the measurement of trace elements in atmospheric aerosols, which are an important source of trace elements to many areas of the oceans. In addition, the investigators will determine the sources of dust and aerosol particles, and quantify the amounts of trace metals delivered to the surface ocean, where they provide essential nutrients to phytoplankton blooms. The new observational data from this project can be used to support both atmospheric and ocean models for coupled air-sea interaction simulations and projections, promoting interdisciplinary sciences. This project will make significant broader impacts by involving female and minority students in research at both the doctoral and undergraduate levels. The lead investigator will incorporate the results from this project into her teachings to promote classroom learning with examples of real-world research, and she will actively participate in the GEOTRACES outreach program to contribute to its education activities. The primary goal of this project is to quantify the key properties of atmospheric trace elements and their fluxes to the Amundsen Sea. The ultimate goal is to advance the knowledge of the atmosphere-ocean-ice interactions for improved understanding of the Earth climate system. The working objectives of this project are: (1) To determine aerosol composition and mineralogy and to explore the sources of dust and target trace elements, including Fe, Al, Ca, Cd, Co, Cu, K, Mn, Na Ni, P, Pb, Ti, V, and Zn; (2) To measure particle-size distributions of aerosol trace elements, aerosol Fe fractional solubility and speciation, organic/inorganic ligands including oxalate and ammonium, and marine biogenic tracers including methanesulfonate and non-sea-salt sulfate and to understand better trace element solubility and processes affecting them; (3) To quantify total atmospheric fluxes of trace elements by both dry deposition and wet deposition processes, contributing to understanding trace element distributions in seawater. Aerosol samples collected on the GP17-ANT cruise will be analyzed for concentrations, composition and mineralogy by utilizing inductively coupled plasma mass spectrometry (ICPMS), synchrotron-based X-ray absorption spectroscopy (XAS) and scanning electron microscopy (SEM). Air mass back trajectory-based cluster analyses will be performed for different air mass provinces impacting the study region. Iron solubility and speciation in aerosol samples will be measured using UV/VIS spectrophotometry and synchrotron-based XAS. Ion chromatography will be utilized to determine water-soluble organic and inorganic species of marine origins. Trace elements in size-segregated aerosols and precipitation will be measured. Atmospheric deposition models will be used to calculate the deposition fluxes to the Amundsen Sea.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.