Collaborative Research: US GEOTRACES GP17-OCE and -ANT Sections: External sources, cycling and processes affecting mercury in the South Pacific and Southern Oceans

合作研究：US GEOTRACES GP17-OCE 和 -ANT 部分：影响南太平洋和南大洋汞的外部来源、循环和过程

• 批准号: 2349825
• 负责人: Silvia Newell
• 金额: $ 37.85万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-10-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2349825&HistoricalAwards=false
• 关键词: Collaborative; Research; US; GEOTRACES; GP17

This project will evaluate the concentrations of mercury (Hg) in its various forms in the ocean and atmosphere to examine the factors that control its concentration and chemistry in remote regions of the ocean. The proposed work will examine mercury sources, primarily from the atmosphere, and how mercury is finally removed from ocean waters. Specifically, this study is focused on the South Pacific and Southern Ocean around Antarctica, regions that are remote from human activity and their associated Hg inputs to the biosphere. Human activity has substantially enhanced the amount of Hg in the biosphere and its levels in seafood consumed by humans, and therefore their potential exposure, but its impact in these remote regions is poorly constrained. The measurements will be made during two ocean expeditions that form part of the international GEOTRACES program. GEOTRACES aims to examine the concentrations and distributions of trace elements and their isotopes in the atmosphere, surface and deep oceans of the world. Mercury is a primarily a concern because of its ability to bioaccumulate in marine food chains, primarily in its organic form, methylmercury (MeHg). Elevated levels of MeHg in fish and other marine organisms is a concern for human and wildlife health due to exposure through seafood consumption, and the factors controlling this exposure are not well understood. The proposed work will support three graduate and several undergraduate students across the three participating institutions.During the two expeditions, the research team will collect high resolution data on the concentrations of the primary Hg forms in the atmosphere, the water column, and the sediments, to examine the sources of Hg to these regions and the processes that lead to the conversion of Hg to its more toxic and bioaccumulative form, MeHg. Dissolved and particulate forms of the various Hg species (gaseous elemental Hg, ionic Hg, MeHg and dimethylmercury) will be determined in the atmosphere and throughout the water column using high resolution sampling and novel techniques. Additionally, measurements of Hg stable isotopes in atmospheric and water samples will be used to identify sources (e.g., geogenic or anthropogenic inputs) and delivery mechanisms (e.g., dry or wet deposition, glacial melt) of Hg to these regions. This comprehensive project will leverage Hg speciation and Hg source tracking capabilities to assess the importance of human activity and climate change in altering the amount of Hg and MeHg in these ocean waters, and the resultant levels in marine organisms consumed by humans.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.

该项目将评估海洋和大气中各种形式的汞（Hg）的浓度，以研究控制海洋偏远地区汞浓度和化学成分的因素。拟议的工作将研究汞的来源（主要来自大气），以及汞最终如何从海水中去除。具体来说，这项研究的重点是南极洲周围的南太平洋和南大洋，这些地区远离人类活动及其对生物圈的相关汞输入。人类活动大大增加了生物圈中的汞含量以及人类食用的海鲜中的汞含量，从而增加了潜在的接触量，但其对这些偏远地区的影响却很少受到限制。这些测量将在构成国际 GEOTRACES 计划一部分的两次海洋探险期间进行。 GEOTRACES 旨在检查世界大气、表面和深海中微量元素及其同位素的浓度和分布。汞之所以成为人们关注的一个主要问题，是因为它能够在海洋食物链中进行生物累积，主要以有机形式甲基汞 (MeHg) 的形式存在。由于食用海鲜而导致鱼类和其他海洋生物体内甲基汞含量升高，这对人类和野生动物的健康构成了担忧，而控制这种暴露的因素尚不清楚。拟议的工作将为三个参与机构的三名研究生和几名本科生提供支持。在两次考察期间，研究小组将收集有关大气、水柱和沉积物中主要汞形式浓度的高分辨率数据，研究这些地区汞的来源以及导致汞转化为其毒性和生物累积性更强的形式甲基汞的过程。将使用高分辨率采样和新技术测定大气和整个水柱中各种汞种类（气态元素汞、离子汞、甲基汞和二甲基汞）的溶解形式和颗粒形式。此外，大气和水样中汞稳定同位素的测量将用于确定这些地区汞的来源（例如，地质或人为输入）和输送机制（例如，干或湿沉积、冰川融化）。这个综合项目将利用汞形态和汞源追踪能力来评估人类活动和气候变化对改变这些海水中汞和甲基汞含量的重要性，以及人类消耗的海洋生物中由此产生的水平。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。