Collaborative Research: US GEOTRACES GP17-OCE and GP17-ANT: Pb Isotopes

合作研究：美国 GEOTRACES GP17-OCE 和 GP17-ANT：Pb 同位素

• 批准号: 2147761
• 负责人: Franco Marcantonio
• 金额: $ 37.46万
• 依托单位: Texas A&M University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-15 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2147761&HistoricalAwards=false
• 关键词: Collaborative; Research; US; GEOTRACES; GP17

Although most of the chemical element lead (Pb) found in the ocean is derived from human emissions to the atmosphere, natural sources of Pb may be important in remote locations such as the Southern Ocean. Natural sources of Pb are derived from the Earth’s crust and are delivered to the ocean by glacial erosion and aerosol inputs. Lead is produced by radioactive decay and has three stable isotopes that are derived from the decay of uranium and thorium. Thus, distinct lead isotope ratios are seen in deposits from source rocks of different ages. These isotope ratios make it possible to distinguish whether pollutant lead in the ocean is derived from American, Australian, European, and Chinese sources. Isotope measurements of Pb provide information about temporal changes in the global transport of pollutants by atmospheric aerosols and the distribution of contaminants and other elements by ocean circulation and particulate transport. In this project, water samples will be collected from the South Pacific sector of the Southern Ocean to help establish the origins of anthropogenic lead in this ocean region, distinguish it from natural lead from the Antarctic continent, and understand the dispersal of Pb by ocean circulation. The project will support one graduate student and one early career postdoctoral scholar.The proposed work will be carried out as part of the GEOTRACES trace element and isotope sampling expedition to the South Pacific and Pacific sector of the Southern Ocean. The measurement of Pb isotopes during these expeditions will provide the ability to trace the source, fate, and transport of other particle-reactive metals in the ocean. Water column, sediment core top and aerosol samples will be analyzed for the full suite of Pb isotopes (204, 206, 207, 208) to provide insights into the extent of anthropogenic Pb contamination in the water column, the relative contribution of different lead isotopes from the South American continent, significance of hydrothermal Pb input from Pacific-Antarctic Ridge and whether sediment Pb isotopes reflect variation in the atmospheric circulation pattern. This work will allow evaluation of various anthropogenic and natural processes that determine the global distributions and processes of Pb.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.

尽管海洋中发现的大部分化学元素铅 (Pb) 来自人类排放到大气中的物质，但铅的天然来源在南大洋等偏远地区可能很重要。铅的天然来源来自地壳和地壳。通过冰川侵蚀和气溶胶输入进入海洋。铅是由放射性衰变产生的，并且具有源自铀和钍衰变的三种稳定同位素，因此，可以看到不同的铅同位素比率。这些同位素比率可以区分海洋中的污染物铅是否来自美国、澳大利亚、欧洲和中国的来源。铅的同位素测量提供了有关污染物全球迁移的时间变化的信息。在该项目中，将从南大洋的南太平洋部分采集水样，以帮助确定该地区人为铅的来源。该项目将支持一名研究生和一名早期职业博士后学者。拟议的工作将作为 GEOTRACES 追踪的一部分进行。对南太平洋和南大洋太平洋部分的元素和同位素采样考察在这些考察过程中对铅同位素的测量将提供追踪海洋中其他颗粒反应金属的来源、命运和运输的能力。将分析水柱、沉积物核心顶部和气溶胶样品的全套铅同位素（204、206、207、208），以深入了解水柱中人为铅污染的程度、不同铅同位素的相对贡献南美大陆的热液铅输入的重要性以及沉积物铅同位素是否反映了大气环流模式的变化这项工作将有助于评估。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。