US GEOTRACES GP17-OCE and GP17-ANT: Particulate and biogenic trace elements in the South Pacific and Southern Ocean

美国 GEOTRACES GP17-OCE 和 GP17-ANT：南太平洋和南大洋的颗粒和生物微量元素

• 批准号: 2049272
• 负责人: Benjamin Twining
• 金额: $ 54.32万
• 依托单位: Bigelow Laboratory for Ocean Sciences
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-10-01 至 2024-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2049272&HistoricalAwards=false
• 关键词: US; GEOTRACES; GP17; OCE; ANT

The goal of the international GEOTRACES program is to understand the distributions of trace chemical elements and their isotopes in the oceans. Many trace metals, such as iron, manganese and zinc, are essential for life and serve as nutrients for phytoplankton. However, regions of the Pacific and Southern Oceans have very low concentrations of iron and manganese, in particular, limiting the growth of phytoplankton at times. This project will improve understanding of the uptake and removal of micronutrient metals by phytoplankton in these regions. This project will accomplish three main objectives: 1) measure the concentrations of phosphorus and eleven trace metals in particles collected from the upper region of the South Pacific and Southern Oceans during a cruise from Tahiti to Chile; 2) measure a subset of these elements, along with carbon, sulfur and silicon, directly in phytoplankton cells collected from these waters; and 3) measure the same elements in phytoplankton collected from coastal Antarctic waters on a subsequent, companion cruise into the Amundsen Sea. Two undergraduate student interns will be involved in the project, along with a postdoctoral scholar. The scientific results and research experience will be shared with additional undergraduates through two classes, and the project will be brought to the broader public through a virtual reality game and associated activities produced during the project and introduced through libraries and institutional outreach events.The U.S. GEOTRACES GP17-OCE expedition, planned for late 2022, aims to determine the distribution of trace elements and isotopes along a transect spanning regions of global importance to nutrient and carbon cycling, crossing the South Pacific Gyre, the iron-limited waters of the Antarctic Circumpolar Current, Pacific Deep Waters with hydrothermal inputs, and waters near the Chilean margin. The South Pacific Gyre and Pacific sector of the Southern Ocean are climate-critical regions for the transfer of heat, carbon, and nutrients within the global ocean, and they are a region where phytoplankton growth is typically limited by low concentrations of iron (Fe) in the surface ocean. The researchers will use inductively-coupled plasma mass spectrometry and synchrotron x-ray fluorescence microscopy to address three primary research questions focused on the internal biogeochemical cycling of trace elements in this region: 1) How do trace element contents of dominant phytoplankton taxa respond to environmental macronutrient and trace element gradients? 2) How does the trace element composition of the various particulate matter fractions (lithogenic, authigenic, biogenic) vary across the section? 3) How does the composition and stoichiometry of particulate material influence trace element cycling and trace element:nutrient stoichiometry of the surrounding water masses?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.

国际地理计划计划的目标是了解痕量化学元件及其同位素在海洋中的分布。许多痕量金属，例如铁，锰和锌，对生命至关重要，是浮游植物的营养。但是，太平洋和南大洋地区的铁和锰浓度很低，尤其是限制了浮游植物的生长。该项目将提高对这些地区浮游植物对微量营养素金属的摄取和去除的理解。该项目将实现三个主要目标：1）在从大溪地到辣椒的巡航过程中，测量从南太平洋和南大洋上部收集的颗粒中磷的浓度和11个痕量金属； 2）直接在从这些水域收集的浮游植物细胞中测量这些元素的子集以及碳，硫和硅； 3）测量从南极沿海水域收集的浮游植物中的相同元素，随后的同伴巡游进入阿蒙森海。两名本科生实习生将与博士后学者一起参与该项目。科学的结果和研究经验将通过两个课程与其他本科生共享，该项目将通过项目期间的虚拟现实游戏和相关活动带给更广泛的公众，并通过图书馆和机构外展活动引入。碳循环，穿越南太平洋回旋，南极圆极电流的铁限水，太平洋深水，带有水热输入，以及智利边缘附近的水。南大洋的南太平洋回旋和太平洋地区是全球海洋中热，碳和养分转移的气候关键区域，它们是浮游植物生长通常受地表海中铁（FE）低浓度限制的地区。研究人员将使用电感耦合的等离子体质谱法和同步X射线荧光显微镜来解决三个主要的研究问题，重点介绍了该区域中痕量元素的内部生物地球化学循环：1）痕量的痕量元素元素对主要植物植物分类的元素如何响应环境大元素元素元素和跟踪元素效果和痕量元素渐变效应量和痕量元素？ 2）各个部分的各种颗粒物分数（岩性，身材，生物源）的微量元素组成如何变化？ 3）颗粒物质的组成和化学计量如何影响痕量元素循环和痕量元素：周围水质量的养分化学计量？该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准通过评估来获得支持的。