ETBC: Collaborative Research: Evaluating the Role of Submarine Groundwater Discharge in the Oceanic Nd Budget

ETBC：合作研究：评估海底地下水排放在海洋 Nd 预算中的作用

• 批准号: 0825920
• 负责人: Karen Johannesson
• 金额: $ 35.66万
• 依托单位: Tulane University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-10-01 至 2012-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0825920&HistoricalAwards=false
• 关键词: ETBC; Collaborative; Research; Evaluating; Role

A number of unresolved questions remain concerning the oceanic neodymium (Nd) budget which limits our understanding of the geochemistry of this rare earth metal and the interpretation of the paleoceanographic Nd isotope record. Amongst the issues is the apparent uncoupling of Nd isotope ratios and Nd concentrations in the oceans, or the so-called 'Nd paradox,' as well as poor constraint on the magnitude and isotopic composition of Nd fluxes to the oceans. Scientists from Tulane University and Old Dominion University, on the basis of preliminary data, hypothesize that submarine groundwater discharge to the ocean is the source of the 'missing Nd flux' required to balance the Nd budget, and that these fluxes also play a role in controlling the Nd isotopic composition of the marine environment. To test their hypothesis, the scientists plan to obtain groundwater Nd concentrations and isotope ratios from a range of locations that discharge to the coastal oceans. Resultant data would be used to develop a global mass balance model to determine whether measured Nd concentrations and isotope ratios of submarine groundwater discharge are sufficient to balance the oceanic Nd budget. The model would also be used to evaluate the impact of varying groundwater Nd fluxes, and their associated isotopic composition, on the paleoceanographic Nd isotope record preserved in hydrogenous sediments.As regards broader impacts, results from this research would be incorporated into classes taught by both scientists at their respective universities. One graduate student and one undergraduate student from Tulane University and one graduate student from Old Dominion University would be supported and trained as part of this project.

关于海洋钕（Nd）的收支仍存在一些未解决的问题，这限制了我们对这种稀土金属的地球化学的理解和对古海洋学Nd同位素记录的解释。 其中的问题是明显的解耦合的Nd同位素比值和Nd浓度在海洋中，或所谓的“Nd悖论”，以及穷人的约束Nd通量的大小和同位素组成的海洋。 杜兰大学和Old自治领大学的科学家根据初步数据推测，海底地下水排放到海洋是平衡Nd收支所需的“缺失Nd通量”的来源，这些通量也在控制海洋环境的Nd同位素组成方面发挥作用。 为了验证他们的假设，科学家们计划从一系列排放到沿海海洋的地点获得地下水Nd浓度和同位素比率。 由此产生的数据将被用来开发一个全球质量平衡模型，以确定是否测量的Nd浓度和同位素比值的海底地下水排放是足够的，以平衡海洋Nd预算。 该模型还将被用来评估不同的地下水钕通量的影响，以及相关的同位素组成，对保存在氢sediments.As古海洋钕同位素记录更广泛的影响，从这项研究的结果将被纳入课堂上教授的科学家在各自的大学。 杜兰大学的一名研究生和一名本科生以及旧自治领大学的一名研究生将作为该项目的一部分得到支助和培训。