Collaborative Research: GEOTRACES Arctic Section: Marine Cycling of Bioactive Trace Metals in the Arctic Ocean

合作研究：GEOTRACES 北极部分：北冰洋生物活性微量金属的海洋循环

• 批准号: 1540254
• 负责人: Seth John
• 金额: $ 51.59万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-02 至 2019-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1540254&HistoricalAwards=false
• 关键词: Collaborative; Research; GEOTRACES; Arctic; Section

In this project, a group of investigators participating in the 2015 U.S.GEOTRACES Arctic expedition will study the chemistry and regional distribution of seven trace metals in the Arctic Ocean: iron, manganese, zinc, cadmium, copper, nickel, and cobalt. These so-called bioactive metals are of special scientific interest because of their role in multiple biogeochemical processes including biological production of the sea and the planetary cycling of carbon and nitrogen. Like other multinational initiatives in the International GEOTRACES Program, the goals of the U.S. Arctic expedition are to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions. This study in particular would contribute to our understanding of the sources and sinks of these seven bioactive metals as well as examine their interaction with biological processes. The project will focus on two major overarching research questions: (1) What are the sources and sinks for micronutrients and macronutrients in the Arctic? And (2) How does bioactive trace element nutrition influence productivity and species composition in the Arctic, and conversely, how do biological processes influence the cycling of these metals? In terms of broader impacts, the PIs on this project will be actively involved in educational outreach efforts, and the research team itself will include two postdoctoral researchers and a graduate student. The team leaders also plan to publish a children's ocean education book based on the expedition with the aim of generating next-generation excitement about modern ocean scienceWIth regard to technical specifics, the research team will measure the dissolved seawater phases of the bioactive metals Fe, Mn, Zn, Cd, Cu, Ni, and Co, the dissolved stable metal isotopes 56Fe, 66Zn, and 114Cd, and the chemical speciation of Co. The recent development of methods for multi-element and multi-isotope analysis methods, in conjunction with the high-resolution sampling of the GEOTRACES program, make it possible to efficiently produce this dense dataset of metals and metal isotopes. This will be a team-based approach to achieve comprehensive duplication for analysis of the key parameters of dissolved metal concentrations. Each investigator will further conduct specialized additional measurements of metal isotopes and dissolved Co (which has unique analytical challenges) and Co speciation. Interpretation of these rich datasets would will be directed toward determination of sources and sinks as well as their ecological stoichiometry, in collaboration with other U.S.GEOTRACES participants measuring synergistic parameters. Together, this Arctic Ocean bioactive trace metal dataset is expected to provide an important contribution to the understanding of micronutrient roles in Arctic biogeochemical processes. These results should also be highly relevant to research studies of the ancient ocean, in which trace-metal analyses are commonly used to trace a wide variety of processes including paleo-ocean circulation and biological productivity. Finally, understanding the sources and sinks for elements in the modern ocean is key to predicting how the concentrations of bioactive elements might vary in a changing future climate.

在该项目中，一组参加2015年美国GEOTRACES北极考察的研究人员将研究北冰洋中七种微量金属的化学和区域分布：铁，锰，锌，镉，铜，镍和钴。 这些所谓的生物活性金属具有特殊的科学意义，因为它们在多种生物地球化学过程中发挥作用，包括海洋的生物生产以及碳和氮的行星循环。 与国际GEOTRACES计划中的其他多国倡议一样，美国北极考察的目标是确定控制海洋中关键微量元素和同位素分布的过程和量化通量，并确定这些分布对环境条件变化的敏感性。 特别是这项研究将有助于我们了解这七种生物活性金属的源和汇，以及研究它们与生物过程的相互作用。 该项目将侧重于两个主要的首要研究问题：（1）北极微量营养素和常量营养素的源和汇是什么？ 以及（2）生物活性微量元素营养如何影响北极的生产力和物种组成，反过来说，生物过程如何影响这些金属的循环？ 就更广泛的影响而言，该项目的PI将积极参与教育推广工作，研究团队本身将包括两名博士后研究人员和一名研究生。考察队负责人还计划根据这次考察出版一本儿童海洋教育书籍，目的是激发下一代对现代海洋科学的兴趣。考虑到技术细节，研究小组将测量生物活性金属Fe，Mn，Zn，Cd，Cu，Ni和Co的溶解海水相，溶解稳定金属同位素56 Fe，66 Zn和114 Cd，多元素和多同位素分析方法的最新发展，加上GEOTRACES计划的高分辨率采样，使得有可能有效地产生这种密集的金属和金属同位素数据集。这将是一个以团队为基础的方法，以实现对溶解金属浓度关键参数分析的全面复制。每位研究人员将进一步对金属同位素和溶解的钴（具有独特的分析挑战）和钴形态进行专门的额外测量。 这些丰富的数据集的解释将被导向确定源和汇以及它们的生态化学计量，与其他美国GEOTRACES参与者合作测量协同参数。 总之，这北冰洋生物活性痕量金属数据集预计将提供一个重要的贡献，了解微量营养素在北极地球化学过程中的作用。 这些结果也应该与古代海洋的研究高度相关，其中微量金属分析通常用于追踪各种过程，包括古海洋环流和生物生产力。最后，了解现代海洋中元素的来源和汇是预测生物活性元素浓度在未来气候变化中如何变化的关键。