Collaborative Research: GEOTRACES Arctic Section: Radium and Thorium Isotopes as Natural Geochemical Tracers in the Arctic Ocean

合作研究：GEOTRACES 北极部分：镭和钍同位素作为北冰洋的天然地球化学示踪剂

• 批准号: 1458305
• 负责人: Matthew Charette
• 金额: $ 124.45万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-15 至 2019-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1458305&HistoricalAwards=false
• 关键词: Collaborative; Research; GEOTRACES; Arctic; Section

In this project, investigators participating in the 2015 U.S. GEOTRACES Arctic expedition will measure radium and thorium isotopes in the western Arctic Ocean. In common with other national 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. Some trace elements are essential to life, others are known biological toxins, and still others are important because they can be used as tracers of a variety of physical, chemical, and biological processes in the sea. The radionuclides to be measured as part of this project are important because they are oceanographic tracers that provide information on rates of cycling of other trace elements. The project will involve training opportunities for graduate student researchers and for undergraduate students from under-represented groups. Results from the study will be shared publicly through the Woods Hole Oceanographic Institution?s Center for Marine and Environmental Radioactivity.While other GEOTRACES projects will map the distribution of numerous trace elements and their isotopes (TEIs), their distribution cannot be properly interpreted without concurrent measurement of tracers capable of providing rates of internal TEI cycling processes and fluxes at boundaries and across interfaces. The isotopes to be measured in this project include a suite of uranium/thorium series radionuclides, including the shorter-lived 234-Th and 228-Th as well as the radium quartet (224-Ra, 223-Ra, 228-Ra, 226-Ra). These tracers have the appropriate half-lives and reactivities to allow for study of horizontal and vertical transport and mixing, as well as removal at ocean boundaries, supply via rivers and submarine groundwater discharge, surface scavenging and export and subsurface remineralization. The researchers have considerable experience developing and implementing the most efficient methods to sample and quantify this suite of tracers, which includes use of battery powered in-situ pumps for large volume sampling. Hence, in addition to the proposed work on uranium/thorium series radionuclides, the team will also provide a service to other GEOTRACES researchers by coordinating pump use and sampling for many essential particulate TEIs.

在该项目中，参加2015年美国地理探险队的调查人员将测量西部北极海洋中的镭和th radium同位素。美国北极探险队的目标是与国际地理计划计划中的其他国家倡议共同确定过程，并量化控制海洋中关键的微量元素和同位素分布的通量，并确定这些分布对改变环境条件的敏感性。一些痕量元素对生命至关重要，另一些是已知的生物毒素，而另一些则很重要，因为它们可以用作海洋中各种物理，化学和生物过程的示踪剂。作为该项目的一部分，要测量的放射性核素很重要，因为它们是海洋示踪剂，可提供有关其他痕量元素循环速率的信息。该项目将涉及研究生研究人员和来自代表性不足小组的本科生的培训机会。 Results from the study will be shared publicly through the Woods Hole Oceanographic Institution?s Center for Marine and Environmental Radioactivity.While other GEOTRACES projects will map the distribution of numerous trace elements and their isotopes (TEIs), their distribution cannot be properly interpreted without concurrent measurement of tracers capable of providing rates of internal TEI cycling processes and fluxes at boundaries and across interfaces.该项目中要测量的同位素包括一套铀/ther序列的放射性核素，包括较短的234-th和228-th和228-以及辐射四重奏（224-RA，223-RA，228-RA，228-RA，226-RA）。这些示踪剂具有适当的半衰期和反应率，可以研究水平和垂直运输和混合，以及在海洋边界上的去除，通过河流和海底地下水排放，表面清除，出口以及地下的回想起。研究人员具有开发和实施最有效的方法来采样和量化这套示踪剂的经验，其中包括使用电池供电的原位泵进行大量抽样。因此，除了提出的铀/ther系列放射性核素的拟议工作外，该团队还将通过协调泵的使用和对许多必需的颗粒物TEIS进行泵的使用和采样来为其他地理位置研究人员提供服务。