Collaborative Research: US GEOTRACES GP17-ANT: Constraining the Neodymium (Nd) Isotope and Rare Earth Element Cycles near the Amundsen Sea Continental Margin

合作研究：美国 GEOTRACES GP17-ANT：限制阿蒙森海大陆边缘附近的钕 (Nd) 同位素和稀土元素循环

• 批准号: 2049554
• 负责人: Xinyuan Zheng
• 金额: $ 47.29万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-15 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2049554&HistoricalAwards=false
• 关键词: Collaborative; Research; US; GEOTRACES; GP17

Trace elements in seawater are relevant to climate and human society, because they can act as essential nutrients for marine ecosystems or useful chemical fingerprints for a variety of oceanographic processes. The international GEOTRACES program is intended to identify processes and quantify fluxes that control the distributions of key trace elements and their isotopes in the global ocean, and to establish how these distributions could respond to changing environments. Neodymium (Nd) isotopes and rare earth elements (REEs) are notable examples of such key elements because of their utility in tracing past and present ocean mixing and sources of trace elements to the ocean. In this project, investigators will participate in the US GEOTRACES science expedition GP17-ANT to the Amundsen Sea sector of the Antarctic continental margin, and analyze Nd isotope ratios and REE concentrations in samples collected from this expedition. This region of the ocean is of particular significance because it is experiencing rapid environmental changes in the past few decades, including the fastest melting of ice shelves around the entire Antarctic. Measurements from this project will advance our understanding of ocean processes that cause melting of local ice shelves, and also will shed new light on nutrient sources that sustain the unusually high biological productivity in the upper ocean of this region. This project will contribute to support the development of diverse involvement in Antarctic research, teaching and outreach efforts across career levels. The outreach activities will provide ample opportunities to engage K-12 students, students from underrepresented groups, and general public in discussions of ocean sciences and the Antarctic environment in both formal and informal settings.The US GEOTRACES GP17-ANT cruise to the Amundsen Sea provides an exceptional opportunity to study marine biogeochemical cycles of trace elements and their isotopes in relation to the Antarctic continental margin, fast iceshelf melting, productive polynyas, and water mass processes in an area especially susceptible to ongoing climate change. This project will study sources and processes that regulate the distribution of Nd isotopes and REEs in seawater in this region. Specific sources and processes that will be studied, and quantified where possible, include: (1) water mass transport and mixing; (2) slope exchange; (3) aerosols; (4) sea ice; (5) subglacial meltwaters; (6) sediments and shelf exchange; (7) particle interactions. Nd isotope and REE concentration analyses will be conducted on a suite of carefully selected seawater, particulate, sediment, aerosol, and sea ice samples to constrain the nature and relative significance of these different controls, providing a comprehensive understanding of Nd isotope and REE cycling in the Antarctic margin. These results will not only provide critical constraints on water mass processes and lithogenic inputs that are directly relevant to understand all other trace element biogeochemical cycles in this region, but also improve the utility of Nd isotopes and REE patterns as useful tracers for studies of modern and ancient oceans.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.

海水中的微量元素与气候和人类社会有关，因为它们可以充当海洋生态系统的必要营养素或用于各种海洋学过程的有用的化学指纹。国际地理环境计划旨在识别流程和量化磁通量，以控制关键的痕量要素及其在全球海洋中的分布，并确定这些分布如何对不断变化的环境做出响应。 Neododymium（ND）同位素和稀土元素（REE）是此类关键元素的显着例子，因为它们在追踪过去和现在的海洋混合和痕量元素到海洋的源头方面有用。在该项目中，研究人员将参加美国的Amundsen Sea Sea部门的美国地理学科学探险GP17-ANT南极大陆边缘的Amundsen Sea部门，并分析了从这次探险队收集的样品中ND同位素比和REE浓度。海洋地区特别重要，因为它在过去几十年中正在经历迅速的环境变化，包括整个南极周围冰架最快的融化。该项目的测量将提高我们对导致当地冰架熔化的海洋过程的理解，并将为养分来源提供新的启示，这些养分来源维持该地区上海上海洋异常高的生物学生产力。该项目将有助于支持各种职业水平的南极研究，教学和外展工作的发展。外展活动将提供充足的机会，让K-12学生，来自人为人数不足的团体的学生以及公众在正式和非正式环境中的海洋科学和南极环境中进行讨论。在一个特别容易受到持续的气候变化的区域中，ICESHELF融化，生产性Polynyas和水量过程。该项目将研究调节该地区海水中ND同位素和REE的分布的来源和过程。特定的来源和过程将在可能的情况下进行研究和量化，包括：（1）水量运输和混合； （2）坡度交换； （3）气溶胶； （4）海冰； （5）冰川融化; （6）沉积物和货架交换； （7）粒子相互作用。 ND同位素和REE浓度分析将在精心选择的海水，颗粒，沉积物，气溶胶和海冰样品的套件上进行，以限制这些不同对照的性质和相对意义，从而对ND同位素和REE循环在反近极余量中的全面了解。 These results will not only provide critical constraints on water mass processes and lithogenic inputs that are directly relevant to understand all other trace element biogeochemical cycles in this region, but also improve the utility of Nd isotopes and REE patterns as useful tracers for studies of modern and ancient oceans.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 标准。

项目成果

Reversible scavenging and advection – Resolving the neodymium paradox in the South Atlantic

可逆清除和平流 — 解决南大西洋的钕悖论

• DOI: 10.1016/j.gca.2021.09.015
• 发表时间: 2021
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: Wang, Ruixue;Clegg, Josephine A.;Scott, Peter M.;Larkin, Christina S.;Deng, Feifei;Thomas, Alexander L.;Zheng, Xin-Yuan;Piotrowski, Alexander M.
• 通讯作者: Piotrowski, Alexander M.