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

该项目将支持管理和实施为期60天的南极大陆边缘阿蒙森海区研究邮轮，以收集用于测量一系列痕量元素和同位素(“TEI”)的样本，这是美国地理跟踪计划的一部分。地理示踪是化学海洋学领域的一项全球性努力，其目标是了解海洋中痕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。关键的TEI包括铁和锌等必需的微量营养素；铝、锰以及可用于研究现代和古代海洋过程的氮、钍和钕的同位素；以及指示人类活动的元素，如铅。在南大洋，南极大陆边缘是铁等微量营养素的重要来源，铁是支持南极大陆架和南极绕极洋流近海生物生产和碳输出所必需的。此外，这些区域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，TEIS提供了测试和完善地球系统数值模型所需的关键数据。阿蒙森海区尤其令人感兴趣，因为与该地区接壤的冰川冰架的融化速度在十年尺度上显著增加，这是由温暖的环极深水侵入大陆架所推动的。这种融化对全球海平面、罗斯海南极底层水的形成以及区域生态系统都有潜在的重大影响。邮轮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、营养物质、藻类色素)，以支持多个单独的科学项目，遵循之前美国地理跟踪邮轮在大西洋、太平洋和北冰洋盆地的成功模式。邮轮将对100W至135W之间的海洋区域进行采样，站点范围从南极绕极洋流中的67°S向南到阿蒙森海大陆架，包括毗邻几个快速融化的冰架和高生产力大陆架的站点。将使用常规和微量金属清洁的CTD花环系统、现场大流量泵和拖曳鱼类采样器或小船，使用既定的方法收集水柱样本。还将为采集海冰、漂浮的冰川冰和海底沉积物提供采样时间。为便利与互补的远洋邮轮的协调，并确保进入研究区域记录生物过程的影响，邮轮计划在夏末(1月下旬至3月下旬)举行。除了学科贡献外，拟议的研究还将提供有关冰冻圈及其对全球海平面和海洋环流的影响、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知识。该项目将通过NSF资助的PolarTREC教育专业人员的参与，以及由罗格斯大学教育专家运营的针对服务不足和代表性不足学校的学生的K-12 STEM计划，为STEM教育和外联做出贡献。为了促进公众参与，调查人员将与UCSC科学传播计划合作，聘请自由职业科学记者在这一壮观而恶劣的南极环境中介绍研究情况。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.