Collaborative Research: US GEOTRACES GP-17-ANT: Molecular speciation of trace element-ligand complexes in the Southern Ocean and Antarctic shelf

合作研究：US GEOTRACES GP-17-ANT：南大洋和南极陆架微量元素-配体复合物的分子形态

• 批准号: 2049280
• 负责人: Rene Boiteau
• 金额: $ 50.02万
• 依托单位: Oregon State University
• 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: 2021-07-15 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2049280&HistoricalAwards=false
• 关键词: Collaborative; Research; US; GEOTRACES; GP

The supply of iron and other biologically essential trace elements to surface waters is a critical regulator of biological growth in the Southern Ocean. Sea ice volume and the physical dynamics of the Southern Ocean are currently experiencing rapid changes. An understanding of the corresponding changes in metal cycling is needed as these elements are essential for the growth of phytoplankton which plays an important role in modulating atmospheric CO2. One of the major knowledge gaps is understanding how soluble forms of these metals are generated and transported to the surface ocean. Many trace elements are insoluble in seawater and precipitate close to their sources unless they are bound to a dissolved organic molecule, or ligand, that keeps the metal in solution. Little is currently known about what these ligands are, where they come from, or how they affect the reactivity and fate of metals in the Southern Ocean. The study proposed here is designed to identify the organic ligands that bind to metals and determine the ligand sources and reactivity along the Antarctic continental margin. The proposed project will survey the molecular speciation of six biologically important trace elements (Fe, Cu, Zn. Ni, Co, Mn) along the US GEOTRACES cruise track along the Antarctic shelf in the Amundsen Sea in order to better understand trace element cycling across the region. The goal of the GEOTRACES expedition is to identify processes and quantify fluxes that control the distributions of trace elements and their isotopes to the Southern Ocean. As part of this effort, the investigators will assess biological ligand production as the ecosystem shifts from low productivity iron-starved conditions in the Antarctic Circumpolar Current to higher productivity along the upwelling continental margin, with a particular focus on assessing production within the Amundsen Sea polynya blooms and sinking organic matter remineralization zones. Second, changes in the accumulation, saturation, and composition of ligands in Circumpolar Deep Water will be measured as the water passes across the Antarctic shelf and receives inputs from sediments and glacial meltwaters. Finally, the role of sea ice on metal-ligand dynamics will be investigated. Metal ligands are a central parameter of numerical ocean models that predict and estimate metal distributions, and results from this project will provide those models with knowledge of the processes that supply ligands and affect ligand concentrations. Two graduate students and undergraduate interns will be supported and trained as part of this project.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.

铁和其他生物学上必不可少的微量元素向地表水的供应是南大洋生物生长的关键调节剂。海冰量和南大洋的物理动态目前正在发生快速变化。需要了解金属循环的相应变化，因为这些元素对于浮游植物的生长至关重要，该元素在调节大气CO2中起着重要作用。主要知识差距之一是了解如何生成这些金属的可溶形式并将其运输到地面海洋。许多痕量元件在海水中不溶于海水，除非它们与溶解的有机分子或配体结合，否则它们将金属保持在溶液中。目前，这些配体是什么，它们来自哪里，或者它们如何影响南大洋中金属的反应性和命运知之甚少。此处提出的研究旨在识别与金属结合的有机配体，并确定沿南极大陆边缘的配体源和反应性。 拟议的项目将调查沿着美国地理沿Amundsen Sea中南极沿着南极架子沿美国地理架沿美国地理架沿美国地理架沿美国地理轨道沿着美国的六个生物学上重要的痕量元件（Fe，Cu，Zn。Ni，Co，MN）的分子形成，以便更好地了解该地区整个地区循环的痕量元素。 Geotraces探险的目标是确定过程并量化控制痕量元素及其同位素对南大洋的分布的通量。作为这项工作的一部分，研究人员将评估生物配体的产生，因为生态系统从南极循环电流中的低生产力铁饥饿条件转变为沿着上升的大陆边缘沿着上升的大陆边缘的较高生产力，特别着重于评估Amundsen Sea Polynya Bloom和沉没有机物的有机物物质回忆ZONE的生产。其次，随着水经过南极架子，将测量配体在圆极深水中的积累，饱和和组成的变化，并从沉积物和冰川融化器中收到输入。最后，将研究海冰在金属配体动力学上的作用。金属配体是数值海洋模型的中心参数，可预测和估计金属分布，该项目的结果将为这些模型提供提供配体并影响配体浓度的过程的知识。作为该项目的一部分，将为两名研究生和本科实习生提供支持和培训。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估。