Collaborative Research: US GEOTRACES GP17-ANT: Tracing Inputs and Transport of Aluminum, Manganese, and Iron from the Amundsen Sea Sector of the Antarctic Continental Margin

合作研究：美国 GEOTRACES GP17-ANT：追踪南极大陆边缘阿蒙森海区铝、锰和铁的输入和运输

• 批准号: 2148091
• 负责人: Joseph Resing
• 金额: $ 26.84万
• 依托单位: University of Washington
• 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: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2148091&HistoricalAwards=false
• 关键词: Collaborative; Research; US; GEOTRACES; GP17

The international GEOTRACES program seeks to understand the distributions of trace elements and their isotopes in the oceans. As part of this effort, the US GEOTRACES program will undertake the GP17-ANT research cruise in November 2023-January 2024, with a focus on the distribution of trace elements and isotopes in the Amundsen Sea sector of the Southern Ocean. Biological production in the Southern Ocean plays an important role in regulating atmospheric carbon dioxide via biological uptake and the associated transfer of organic matter into the ocean interior. Most of this ocean region has abundant major nutrients (nitrogen, phosphorous and silicon) required for phytoplankton growth, but is deficient in the essential micronutrient iron. This means that phytoplankton growth during the summer growing season is regulated by iron. Other trace elements, such as manganese and cobalt, may also hold importance in this context. Hence, there is a compelling need to constrain the sources of these micronutrient trace elements to Southern Ocean surface waters. Chief among these sources are sediments, glaciers and sea ice on the Antarctic continental margins. This project seeks to advance understanding of the sources and transport of the micronutrients iron and manganese in the Amundsen Sea sector of the Southern Ocean, as part of the upcoming GEOTRACES GP17-ANT research expedition. The Amundsen Sea is a highly productive section of the Antarctic continental margin that is bordered by some of Antarctica’s most rapidly melting glacial ice shelves, and is thought to provide an important source of dissolved iron to the adjacent, iron-deficient surface waters of the Antarctic Circumpolar Current. As such, the measurements of trace elements and isotopes during this expedition will provide a critically important benchmark to assess the impacts of major changes that are anticipated for this marine environment during the coming decades, such as inputs of the micronutrient iron that are associated with increased glacial melting. The project involves two US laboratories, and will support the research of a graduate student and an undergraduate student. The project also includes the participation of a K-12 STEM education specialist who will develop educational outreach materials targeting elementary and middle school students and science teachers.In this project, the concentrations of trace elements that serve as micronutrients (dissolved iron and manganese) and tracers of inputs from continental dust and seafloor sediments (dissolved aluminum and manganese) will be measured in seawater samples collected during GP17-ANT. In addition, shipboard experiments will be performed to assess the potential for suspended particles and surface sediments to contribute these dissolved trace elements to surface seawater. This work, together with measurements of other trace elements and isotopes made by collaborators, will assess the sources, transport and chemical transformations of micronutrients in this sector of the Antarctic continental margin, and hence the trajectories of these micronutrient inputs in response to future environmental changes. The chemical analyses of dissolved aluminum, manganese and iron will be performed at sea, in near real-time, thus providing data to inform the cruise sampling strategy and guide the analyses of other investigators.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.

国际GEOTRACES计划旨在了解海洋中微量元素及其同位素的分布，作为这项工作的一部分，美国GEOTRACES计划将于2023年11月至2024年1月进行GP17-ANT研究巡航，重点关注分布。南大洋阿蒙森海区微量元素和同位素的测定 南大洋的生物生产在通过生物吸收和相关转移调节大气二氧化碳方面发挥着重要作用。该海洋区域的大部分地区拥有丰富的浮游植物生长所需的主要营养物质（氮、磷和硅），但缺乏必需的微量营养素铁，这意味着浮游植物在夏季生长季节的生长受到调节。其他微量元素，例如锰和钴，在这方面也可能很重要，因此，迫切需要将这些微量营养元素的来源限制在南大洋表层水中。作为即将开展的 GEOTRACES GP17-ANT 的一部分，该项目旨在增进对南大洋阿蒙森海区微量营养素铁和锰的来源和运输的了解。阿蒙森海是南极洲大陆边缘的一个高产区域，毗邻南极洲一些融化最快的冰川冰架，被认为是一个高产区域。为邻近的南极绕极地流缺铁的地表水域提供重要的溶解铁来源，因此，本次探险期间对微量元素和同位素的测量将为评估重大变化的影响提供至关重要的基准。预计未来几十年对这种海洋环境的影响，例如与冰川融化增加相关的微量营养素铁的输入，该项目涉及两个美国实验室，并将支持该项目的研究生和本科生的研究。包括K-12 STEM 教育专家的参与，他们将开发针对中小学生和科学教师的教育推广材料。在该项目中，作为微量营养素（溶解的铁和锰）的微量元素的浓度以及来自输入的示踪剂将在 GP17-ANT 期间收集的海水样本中测量大陆灰尘和海底沉积物（溶解的铝和锰）。此外，还将进行船上实验，以评估悬浮颗粒和表面沉积物造成这些溶解痕迹的可能性。这项工作连同合作者对其他微量元素和同位素的测量，将评估南极大陆边缘这一地区微量营养素的来源、运输和化学转化，从而评估这些微量营养素输入的轨迹。溶解铝、锰和铁的化学分析将在海上近乎实时地进行，从而为巡航采样策略提供数据并指导其他研究人员的分析。该奖项反映了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，NSF 的法定使命被认为值得支持。