Constraining the air-sea exchange of inorganic and methylated mercury with high resolution spatial and temporal measurements in the Sargasso Sea

通过马尾藻海的高分辨率空间和时间测量限制无机汞和甲基化汞的海气交换

• 批准号: 2319385
• 负责人: Robert Mason
• 金额: $ 68.07万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2319385&HistoricalAwards=false
• 关键词: Constraining; air; sea; exchange; inorganic

Mercury (Hg), a global pollutant, is released to the biosphere predominantly by human activity, through intentional use or as a trace element in coal, ores, and other products. These releases are exacerbated by climate change. Atmospheric Hg is predominantly elemental Hg (Hg0) - a gas with a relatively long residence time that can be transported globally to remote regions. After its transformation by atmospheric chemical reactions to ionic Hg, it is deposited to the ocean through precipitation, aerosol, and gaseous Hg deposition. In surface waters, ionic Hg is biologically and abiotically transformed into Hg0, which is then returned to the atmosphere via gas exchange. Overall, atmospheric deposition is the primary source, and Hg0 gas evasion is the primary loss mechanism for ocean Hg. The extent of air-sea exchange therefore alters the ocean Hg burden and impacts the global mercury cycle. Furthermore, the oceanic ionic Hg can be transformed into the more toxic and bioaccumulative methylmercury (MeHg), which concentrates in seafood sufficiently to be a global human health concern and impact wildlife. Understanding the factors that mediate the air-sea exchange of Hg is of vital importance for assessing the impact of humans and climate change on MeHg levels in seafood, and human health.The project, co-funded by the Chemical Oceanography Program and the Atmospheric Chemistry Program, will evaluate the concentrations of Hg in the surface ocean and atmosphere to examine the factors controlling their concentration and chemistry, and the magnitude of the Hg sources and sinks. There is limited data examining the seasonal and temporal variability of Hg speciation in the surface ocean at a specific location, and its air-sea exchange, and this is the study’s primary focus. Measurements will be made in the North Atlantic Ocean near Bermuda, during both monthly and specific Hg-focused cruises. Atmospheric samples will be collected as well at the atmospheric sampling station in Bermuda. During cruises, high resolution Hg speciation data in the atmosphere (gaseous and aerosol) and surface waters (gaseous elemental Hg, dissolved and particulate ionic Hg, MeHg and dimethylmercury) will be gathered to examine the sources of Hg and its transformations, and how this impacts the formation of MeHg. 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 of Hg to this region. This proposed research will further assess the importance of natural variability, human activity, and climate change on altering Hg and MeHg levels in the ocean, and 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.

汞（HG）是一种全球污染物，主要是通过人类活动，有意使用或作为煤炭，矿石和其他产品的痕量元素释放到生物圈上。这些释放因气候变化而加剧。大气HG主要是元素HG（HG0） - 一种相对长时间的气体可以在全球范围内运输到偏远地区。大气化学反应转化为离子Hg后，它通过降水，气溶胶和气态HG沉积沉积到海洋中。在地表水中，离子HG在生物学和物种上转化为HG0，然后通过气体交换返回大气。总体而言，大气沉积是主要来源，而HG0气体演化是海洋汞的主要损失机制。因此，空气交换的程度改变了海洋汞的燃烧并影响全球汞周期。此外，海洋离子HG可以转变为更具毒性和生物蓄积的甲基汞（MEHG），该甲基汞（MEHG）足够浓度足以成为全球人类健康的关注并影响野生动植物。了解介导HG空气交换的因素对于评估人类和气候变化对海鲜和人类健康中MEHG水平的影响至关重要。该项目由化学海洋学计划和大气化学计划共同资助，将评估HG在表面海洋和大气中的浓度，以检查其浓度和化学的浓度和化学效果和化学量和化学量的因素。有限的数据研究了特定位置及其空气交换的HG规范在地面海洋中的季节性和临时变异性，这是该研究的主要重点。在每月和以hg为中心的特定的巡航期间，将在百慕大附近的北大西洋进行测量。大气样品也将在百慕大的大气采样站收集。在巡航过程中，将收集大气中的高分辨率HG规格数据（气体和气雾剂）和地表水（气态元素HG，溶解和特定的离子HG，MEHG和Dimethylmercury），以检查HG的来源及其转化的来源，以及如何影响MEHG的形成。此外，将使用大气和水样品中HG稳定的同位素的测量来鉴定汞含量的来源（例如，地球或人为输入）和HG向该区域的递送机制。这项拟议的研究将进一步评估自然变异性，人类活动和气候变化对改变海洋中的HG和MEHG水平的重要性，以及在人类消耗的海洋生物中。这项奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评估来通过评估来支持的，这是值得的。