Collaborative Research: Constraining the role of chemical transformations in the cycling of mercury at the Arctic Ocean air-sea interface

该项目将结合对海水中汞形态的研究，提供对北极空气和海面之间汞交换的新认识。研究结果将有助于预测不断增加的冰融化和变暖的沃茨将如何影响极地地区的汞含量。研究人员将使用一种新的方法来比较氡（一种非反应性气体）和汞（一种具有各种形式的反应性气体）的动态，以了解化学和生物反应影响海水中汞含量的重要性。研究结果将有助于国际水俣公约和资源管理人员关注汞在人类和野生动物中的生物累积。该项目将培养一名博士后研究员，他将参与研究的各个方面，并为本科生提供研究经验。研究人员还计划为非专业人员编写宣传出版物，并在他们的网站上突出介绍这项工作。该项目将联合收割机船上测量和孵化实验相结合，以提高我们对无机汞和甲基化汞在水-空气界面上的循环以及冰盖在影响这种交换中的作用的理解。为了将气体交换与表面沃茨中的氧化还原反应和其他转化分开，调查人员将收集样品用于测定氡和镭，因为氡的混合层缺陷可用作气体交换通量的独立估计。调查人员将检验以下假设：1）与其他海洋相比，汞的气体逃逸不是北冰洋水柱汞的主要汇; 2）与大气损失相比，二甲基汞的原位水柱降解是更重要的汇; 3）北极地区汞的净产量相对较低，反映了较低的紫外线水平和冰盖、生产力和生物可利用汞的减少。研究结果将有助于预测甲基汞的生物累积如何被不断变化的气候和不断演变的北极海冰制度所改变。该奖项反映了NSF的法定使命，并被认为值得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来支持。

This project will provide new understanding about mercury exchange between the air and sea surface in the Arctic, in conjunction with studies of the forms of mercury in seawater. Results will help predict how increasing ice melt and warming waters will affect mercury levels in polar regions. The investigators will use a novel approach of comparing the dynamics of radon, an unreactive gas, and mercury, which is reactive in all its forms, to understand the importance of chemical and biological reactions influencing mercury levels in seawater. Results will be useful for the international Minamata Convention and resource managers concerned with mercury bioaccumulation in humans and wildlife. The project will train a post-doctoral investigator, who will be involved in all aspects of the research, as well as provide research experience for undergraduate students. The investigators also plan to create outreach publications for non-specialists and highlight the work on their websites.This project will combine shipboard measurements and incubation experiments to improve our understanding of the cycling of inorganic and methylated mercury across the water-air interface and the role of ice cover in affecting this exchange. To separate gas exchange from redox reactions and other transformations in surface waters, the investigators will collect samples for the determination of radon and radium, as the mixed layer deficit in radon can be used as an independent estimate of the gas exchange flux. The investigators will test the hypotheses that: 1) gas evasion of mercury is not the primary sink for water column mercury in the Arctic Ocean, in contrast to other oceans; 2) in situ water column degradation of dimethylmercury is a more important sink than loss to the atmosphere; and 3) the relatively low net production of mercury in the Arctic reflects lower ultraviolet light levels and ice cover, productivity, and bioavailable mercury for reduction. Results will help predict how the bioaccumulation of methylmercury may be altered by a changing climate and an evolving Arctic sea ice regime.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.