GEOTRACES Arctic Section: Improving understanding of controls on the distributions of selected anthropogenic radionuclides in the Amerasian Basin

在这个项目中，一组参与2015年美国地理痕迹北极探险的调查人员将确定北冰洋一套人为(人造)放射性同位素的浓度。人为放射性同位素是具有人为来源的不稳定元素形式；它们可能作为核武器试验或核能生产的副产品泄漏到环境中。与国际地质勘测计划中的其他多国计划一样，美国北极探险队的目标是确定控制海洋中关键微量元素和同位素分布的过程和通量，并确定这些分布对环境条件变化的敏感性。这项研究的结果将有助于确定人为放射性同位素的不同污染源的特征，并确定导致其在北极观测到的分布的重要机制的影响。研究人员将与美国国家科学基金会资助的极地学习和应对气候变化教育伙伴关系合作，开发基于网络的空间工具，与学生和公众分享他们的工作成果。尽管在北极已经做了大量工作，但放射性核素的数据集在某些情况下完全缺乏或仅限于感兴趣的特定元素或同位素，包括不同来源、水柱、海冰和沉积物的特征。美国地理追踪北极部分提供了一个前所未有的机会来研究北极地区人为放射性核素的来源、去向和运输，该地区一直受到核工业活动的严重影响，并对全球气候变化表现出戏剧性和快速的反应。这些研究人员将使用一种全面、多示踪的方法，确定一套人为放射性核素的浓度，包括来自北极的各种不同类型的样品中的铯-137、铯-134、钚-239、钚-240和钚-237。这项研究将提供有关感兴趣的人为放射性核素的水平和垂直分布的信息，这将大大增加全球数据集，通过与欧洲同事合作，限制若干人为放射性核素的预算，不仅涉及这些污染物在北极的迁移和去向，而且使人们深入了解影响这些污染物的主要过程。这些数据将支持数据建模方面的努力，这将在整个盆地的基础上综合溶解的和颗粒状的人为放射性核素数据，然后比较和评估不同海洋过程的贡献以及污染源的影响。

In this project, a group of investigators participating in the 2015 U.S. GEOTRACES Arctic expedition will determine the concentrations of a suite of anthropogenic (human-made) radioisotopes in the Arctic Ocean. Anthropogenic radioisotopes are unstable forms of elements that have a human-made origin; they may leak into the environment as by-products of nuclear weapons testing or nuclear energy production. In common with other multinational initiatives in the International GEOTRACES program, the goals of the U.S. Arctic expedition are to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions. Results from this research will help to characterize distinct contaminant sources for anthropogenic radioisotopes and identify the influence of important mechanisms that lead to their observed distributions in the Arctic. Researchers will collaborate with the NSF-funded Polar Learning and Responding Climate Change Education Partnership in order to develop web-based spatial tools for sharing results of their work with students and the general public.Although a significant amount of work has been done in the Arctic, data sets on radionuclides are entirely lacking in some cases or limited with respect to particular elements or isotopes of interest including characterization of different sources, water column, sea ice, and sediments. The U.S. GEOTRACES Arctic section offers an unprecedented opportunity to study the sources, fate and transport of anthropogenic radionuclides in the Arctic, a region that has been heavily impacted by nuclear industrial activities and exhibiting dramatic and rapid responses to global climate change. Using a comprehensive, multi-tracer approach, these researchers will determine the concentrations of a suite of anthropogenic radionuclides, including cesium-137, cesium-134, plutonium-239, plutonium-240, and neptunium-237 in a variety of different types of samples from the Arctic. This study will provide information on the horizontal and vertical distributions of the anthropogenic radionuclides of interest, which will substantially add to the global data set, constrain the budgets of several anthropogenic radionuclides through collaboration with European colleagues, and address not only the transport and fate of these contaminants in the Arctic, but also provide insight into the dominant processes that affect them. The data will support efforts in data modeling, which will integrate the dissolved and particulate anthropogenic radionuclides data on a basin-wide basis, and then compare and evaluate the contributions from different oceanic processes as well as the influence of sources of contamination.