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: 2152649
• 负责人: Silvia Newell
• 金额: $ 37.85万
• 依托单位: Wright State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2152649&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浓度，以研究控制海洋偏远地区汞浓度和化学性质的因素。拟议的工作将审查汞的来源，主要是大气中的汞，以及汞最终如何从海洋沃茨中去除。具体而言，本研究的重点是南太平洋和南极洲周围的南大洋，这些地区远离人类活动及其相关的汞输入生物圈。人类活动极大地增加了生物圈中的汞含量和人类食用的海产品中的汞含量，从而增加了汞的潜在暴露量，但其对这些偏远地区的影响却没有得到很好的控制。这些测量将在两次海洋考察期间进行，这是国际GEOTRACES计划的一部分。GEOTRACES旨在研究世界大气、表层和深海中微量元素及其同位素的浓度和分布。汞是一个主要的关切，因为它能够在海洋食物链中生物积累，主要是以其有机形式甲基汞（MeHg）。鱼类和其他海洋生物体内的甲基汞水平升高，是人类和野生动物因食用海产品而接触甲基汞的一个问题，控制这种接触的因素还不清楚。研究团队将在两次考察中收集有关大气、水体和沉积物中主要形态汞浓度的高分辨率数据，以研究这些地区汞的来源以及导致汞转化为毒性更大、生物累积性更强的形态的过程，甲基汞。将使用高分辨率取样和新技术，确定大气和整个水体中各种汞物质（气态元素汞、离子汞、甲基汞和二甲汞）的溶解和颗粒形式。此外，还将使用大气和水样中汞稳定同位素的测量结果来确定汞的来源（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）的汞到这些地区。这一综合项目将利用汞的形态和汞源追踪能力，评估人类活动和气候变化在改变这些海洋沃茨中汞和甲基汞含量方面的重要性，以及人类消耗的海洋生物中汞和甲基汞的含量，该奖项反映了NSF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。