Collaborative Research: Management and Implementation of US GEOTRACES GP17 Section: Amundsen Sea Sector of the Antarctic Continental Margin (GP17-ANT)

作为美国 GEOTRACES 计划的一部分，该项目将支持管理和实施前往南极大陆边缘阿蒙森海区域的为期 60 天的研究航行，以收集样本以测量各种微量元素和同位素（“TEI”）。 GEOTRACES 是化学海洋学领域的一项全球努力，其目标是了解海洋中微量元素及其同位素的分布。确定这些元素和同位素的分布将增加对形成其分布的过程以及依赖于这些元素的过程的理解。关键 TEI 包括必需的微量营养素，例如铁和锌； “示踪剂”，例如铝、锰以及氮、钍和钕的同位素，可用于研究现代和古代海洋过程；以及铅等表明人类活动的元素。在南大洋，南极大陆边缘作为铁等微量营养素的重要来源，是支持南极大陆架和南极绕极流近海水域的生物生产和碳输出所必需的。此外，这些地区正在经历快速的环境变化，预计将影响海洋环流和生物地球化学循环，为此 TEI 提供了测试和完善地球系统数值模型所需的关键数据。阿蒙森海区域特别受关注，因为在温暖的环极深水侵入大陆架的推动下，与该地区接壤的冰川冰架的融化速度在十年间显着增加。这种融化可能会对全球海平面、罗斯海南极底层水的形成以及区域生态系统产生重大影响。该航行将包括基本的采样操作（收集和船上处理）和辅助测量（水文学、营养物、藻类色素），以支持多个单独的科学项目，遵循之前美国 GEOTRACES 在大西洋、太平洋和北冰洋盆地航行的成功模式。该巡游将对西经100°至135°之间的海洋区域进行采样，站点范围从南极绕极流南纬67°一直到阿蒙森海大陆架，包括邻近几个快速融化的冰架和高产陆架冰间湖的站点。将使用常规和痕量金属清洁 CTD 玫瑰花结系统、现场大容量泵以及拖曳式鱼类采样器或小船，使用既定方法收集水柱样品。还将提供采样时间来收集海冰、漂浮冰川冰和海底沉积物。为了促进与互补的公海巡航的协调，并确保进入研究区域以记录生物过程的影响，巡航计划于澳大利亚夏末（一月下旬至三月下旬）进行。除了学科贡献之外，拟议的研究还将贡献有关冰冻圈及其对全球海平面和海洋环流、区域生态系统和生物过程、海洋-大气相互作用以及过去和未来环境变化的影响的知识。该项目将通过 NSF 资助的 PolarTREC 教育专业人士的参与以及为罗格斯大学教育专家运营的服务不足和代表性不足学校的学生提供 K-12 STEM 计划，为 STEM 教育和推广做出贡献。为了促进公众参与，研究人员将与 UCSC 科学传播计划合作，聘请自由科学记者来报道这一壮观而严酷的南极环境中的研究。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。

This project will support the management and implementation of a 60-day research cruise to the Amundsen Sea sector of the Antarctic continental margin to collect samples for measurements of a broad suite of trace elements and isotopes (“TEIs”), as part of the U.S. GEOTRACES program. GEOTRACES is a global effort in the field of Chemical Oceanography, the goal of which is to understand the distributions of trace elements and their isotopes in the ocean. Determining the distributions of these elements and isotopes will increase the understanding of processes that shape their distributions and also the processes that depend on these elements. Key TEIs include essential micronutrients such as iron and zinc; “tracers” such as aluminum, manganese, and isotopes of nitrogen, thorium and neodymium that can be used to investigate modern and ancient ocean processes; and elements such as lead that are indicative of human activities. In the Southern Ocean, the Antarctic continental margins are important as sources of micronutrient trace elements such as iron, which is required to support biological production and carbon export over the Antarctic shelf and in offshore waters of the Antarctic Circumpolar Current. Moreover, these regions are experiencing rapid environmental changes that are expected to impact oceanic circulation and biogeochemical cycles, for which TEIs provide crucial data needed to test and refine numerical models of the Earth system. The Amundsen Sea sector holds particular interest because of the pronounced, decadal-scale increases in the melting rates of glacial ice shelves that border the region, driven by intrusions of warm Circumpolar Deep Water onto the continental shelf. This melting has potentially major impacts on global sea level, on the formation of Antarctic Bottom Water in the Ross Sea, and on the regional ecosystem. The cruise will comprise essential sampling operations (collection and shipboard processing) and ancillary measurements (hydrography, nutrients, algal pigments) in support of multiple, individual science projects, following the successful model of previous U.S. GEOTRACES cruises in the Atlantic, Pacific and Arctic ocean basins. The cruise will sample the ocean region between 100°W and 135°W, with stations ranging from 67°S in the Antarctic Circumpolar Current southward to the Amundsen Sea continental shelf, including stations adjacent to several rapidly melting ice shelves and in highly-productive shelf polynyas. Water column samples will be collected using conventional and trace-metal clean CTD-rosette systems, in-situ high-volume pumps, and a towed fish sampler or small boat, using established methods. Sampling time will also be provided for collection of sea ice, floating glacial ice, and seafloor sediments. To facilitate coordination with a complementary open-ocean cruise and ensure access to the study region to document the impact of biological processes, the cruise is planned for late austral summer (late January-late March). Beyond the disciplinary contributions, the proposed research will contribute knowledge concerning the cryosphere and its impacts on global sea level and ocean circulation, regional ecosystems and biological processes, ocean-atmosphere interactions, and past and future environmental change. The project will contribute to STEM education and outreach through the participation of an NSF-funded PolarTREC education professional, and a K-12 STEM program for students from underserved and underrepresented schools run by Rutgers University education specialists. To foster public engagement, the investigators will partner with the UCSC Science Communication Program to engage freelance science journalists to profile research in this spectacular and harsh Antarctic environment.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.