GEOTRACES Arctic Section: Disequilibria between Radium-226, Lead-210 and Polonium-210 in the Arctic Ocean and their implications for trace metal distribution

GEOTRACES 北极部分：北冰洋中镭 226、铅 210 和钋 210 之间的不平衡及其对痕量金属分布的影响

• 批准号: 1435376
• 负责人: Kanchan Maiti
• 金额: $ 18.61万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-15 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1435376&HistoricalAwards=false
• 关键词: GEOTRACES; Arctic; Section; Disequilibria; between

This project will form part of the 2015 U.S. GEOTRACES Arctic expedition. 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 (TEIs) 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. Within this broader framework, the goal of this project is to measure the naturally occurring radionuclides radium-226 (half-life 1600 years), lead-210 (half-life 22.1 y) and polonium-210 (half-life 138 days) to determine removal rates of particle reactive TEIs from the water column and to study the processes responsible for their scavenging, lateral and vertical transport and accumulation in bottom sediments. A wide range of processes will be encountered along the proposed ARCTIC GEOTRACES section and the proposed study will play a key role in the interpretation of observed TEI distributions and address the following questions: (1) What is the variability in scavenging intensity of polonium and lead between the Pacific waters and that of particle dominated areas of the shelf? (2) How does the scavenging intensity of polonium and lead change across areas of varying nutrient concentrations in the Chukchi Sea? (3) How does the scavenging intensity vary between Canadian Basin and the Makarov Basin? (4) Which are the areas of enhanced sediment focusing in this region and how important is the role of boundary scavenging and lateral transport of particles with respect to lead-210 distribution in water column and sediments? (5) What are the seasonal scale vertical fluxes of particulate organic matter in this region and the relative importance of lateral versus vertical transport of organic matter and other TEIs? (6) How do particle mixing rates vary across the basin and impact reduction rates? (7) Are the bottom waters in the shelf region enriched in polonium-210 due to sediment remobilization? The ability to address these questions will allow better understanding of processes controlling the distribution in this region of other TEIs that will be measured by other investigators. The broader impacts of the research include the involvement of 1 Ph.D. student and at least 2 undergraduate students. The lead investigator is an early-career scientist and this project will help him in extending his expertise in the Arctic region and further development of his career. The investigator is involved in numerous local outreach activities that will provide opportunities for education of the general public and high school students about marine ecosystems and how it affects their environmental well-being. Moreover this research will also be a part of the broader Arctic GEOTRACES outreach program which plans to support the participation of a high-school science teacher on the cruise through partnership with PolarTREC and COSEE-Alaska.

该项目将构成2015年美国北极探险队的一部分。美国北极探险队的目标是与国际地理领域计划中的其他跨国公司计划相同，是识别流程并量化控制海洋中关键痕量元素和同位素（TEIS）分布的通量，并确定这些分布对不断变化的环境条件的敏感性。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。在这个更广泛的框架内，该项目的目标是测量天然存在的放射性核粉radium-226（半衰期1600年），Lead-210（半衰期22.1 Y）和Polonium-210（半寿命138天）（半寿命138天），以确定从水柱中进行粒子反应性TEI的去除速率，以研究水柱的颗粒反应性TEIS，并研究负责其播放的播放和延续的延续和延伸的序列，并累积了序列的累积和累积。沿拟议的北极地理区域部分将遇到广泛的过程，而拟议的研究将在解释观察到的TEI分布的解释中起关键作用，并解决以下问题：（1）polonioum polonium和Pacific Waters的铅的变异性是多少？ （2）在Chukchi Sea中养分浓度不同的地区的polonium强度和铅变化的清除强度如何？ （3）清除强度在加拿大盆地和马卡罗夫盆地之间有何不同？ （4）该区域中焦点的增强区域是哪些区域，粒子在水柱和沉积物中的铅-210分布方面的边界清除和横向运输的作用有多重要？ （5）该区域中颗粒有机物的季节尺度是什么，以及有机物和其他TEI的横向转运与垂直运输的相对重要性？ （6）颗粒混合速率在整个盆地中如何变化和影响降低率？ （7）由于沉积物重新启动，货架区域的底部水是否富含polonium-210？解决这些问题的能力将可以更好地理解控制其他研究人员将衡量的其他TEI区域中分布的过程。该研究的更广泛影响包括1博士学位的参与。学生和至少2名本科生。首席调查员是一名早期职业科学家，该项目将帮助他扩展他在北极地区的专业知识并进一步发展职业生涯。调查人员参与了许多当地的外展活动，这些活动将为公众和高中学生提供有关海洋生态系统及其如何影响其环境健康的机会。此外，这项研究还将成为更广泛的北极地理宣传计划的一部分，该计划计划通过与Polartrec和Colletrec和Cosee-Alaska的合作来支持一位高中科学老师参加巡航的参与。