Lead and Lead Isotope Sample Collection and Analysis for the U.S. GEOTRACES Zonal North Atlantic Survey Section

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)资助的。制定国际地质勘查方案是为了建立一个关键微量元素和同位素的全球框架，该框架将描述这些财产在海洋中的当代分布。然后，这些信息可用于限制生物地球化学重要元素的过程和通量的模型，以及框定通量过程和转化的关键示踪剂。麻省理工学院的一名科学家将在2010年GEOTRACES北大西洋邮轮期间收集样本，并分析它们的铅(铅)和铅同位素。将从显示影响痕量金属及其同位素的物理和生物地球化学过程(即强烈的经向平流、边界清理和来源、风沙沉积、来自地中海和拉布拉多海的中间水的输入以及人为影响的证据)的地点采集样本。这位科学家将利用将要生成的数据集解决以下问题：(1)自1999年以来在副热带大西洋西部和东部演变的海洋中铅和铅同位素的剖面；(2)它们的分布是否与平流输送或下沉颗粒的交换一致；(3)来自热液喷口的铅或铅同位素信号是否在源头之外输送了很远的距离？(4)北大西洋上和下大西洋深水的铅和铅同位素组成有何不同，这些差异在西部边界上是如何横向表达的？此外，由于铅在大气沉积、生物吸收和非生物清除方面的行为与其他痕量金属相似，因此本研究的结果将适用于其他元素。至于更广泛的影响，这项工作将有助于建立更准确的生物地球化学模型，使科学家能够了解未来气候变化和人为污染的影响。作为该项目的一部分，将对一名研究生进行培训和支助。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The international GEOTRACES program has been developed to produce a global framework of key trace elements and isotopes that will describe the contemporary distributions of these properties in the ocean. This information can then be used to constrain models of the processes and fluxes of biogeochemically important elements and key tracers that frame flux processes and transformations. A scientist from Massachusetts Institute of Technology will collect samples during the GEOTRACES North Atlantic cruise in 2010 and analyze them for lead (Pb) and Pb isotopes. Samples will be taken from sites that exhibit the physical and biogeochemical processes that influence trace metals and their isotopes (i.e., strong meridional advection, boundary scavenging and sources, aeolian deposition, input of intermediate waters from the Mediterranean and Labrador Seas, and evidence of anthropogenic impacts). Amongst the questions the scientist will address with the dataset to be generated are the following: (1) have profiles of Pb and Pb isotopes in the ocean evolved in the western and eastern subtropical Atlantic since 1999; (2) is their distribution consistent with advective transport or with exchange on sinking particle; (3) are Pb or Pb isotope signals from hydrothermal vents transported a significant distance beyond the source?; and (4) how do upper and lower North Atlantic Deep Water differ in their Pb and Pb isotopic composition, and how are these differences expressed laterally over the western boundary? In addition, because Pb behaves similarly to other trace metals as regards atmospheric deposition, biological uptake, and abiotic scavenging, results from this study will be applicable to other elements. As regards broader impacts, this work will aid in creating more accurate biogeochemical models allowing scientists to access the impact of future climate change and anthropogenic pollution. One graduate student would be trained and supported as part of this project.