Collaborative Research: U.S. GEOTRACES GP17-OCE: Dissolved concentrations, isotopes, and colloids of the bioactive trace metals

合作研究：美国 GEOTRACES GP17-OCE：生物活性痕量金属的溶解浓度、同位素和胶体

基本信息

批准号：
2049241
负责人：
Jessica Fitzsimmons
金额：
$ 45.68万
依托单位：
Texas A&M 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：
2021-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2049241&HistoricalAwards=false
关键词：
Collaborative Research U.S.GEOTRACES GP17

项目摘要

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, which are by definition present in very low amounts, are essential for life and thus considered nutrients for phytoplankton growth. Other elements can be useful for tracing other ocean processes, and some (such as lead) are important because they are pollutants. This project will address three main objectives: 1) to measure the dissolved concentrations and size partitioning of micronutrients iron, manganese, zinc, copper, cadmium, nickel, and pollutant lead in seawater from Tahiti towards Antarctica and then back northeast to South America; 2) to analyze the isotope ratios - the relative abundance of different forms of the same chemical element - of iron, zinc, cadmium, nickel, and copper in seawater, suspended particles, aerosols, and porewaters from this section, as isotopes provide diagnostic insights into sources, sinks, and metal transformations beyond what is provided by concentration measurements alone; and 3) to use ocean models to constrain the rates of ocean processes and effects of ocean circulation on trace metal and isotope distributions. This project spans three US labs, and four graduate students and several undergraduate students will participate. It will also provide ultrafiltered samples and data to several other collaborating groups as a service.The U.S. GEOTRACES GP17-OCE expedition, planned for late 2021 or 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 investigators will use a variety of analytical approaches, along with analyses made by other project collaborators, to address four major objectives related to dissolved micronutrient biogeochemistry in this region: 1) What are the relative fluxes of dissolved metals from dust, sediments, and Antarctic continental inputs to surface waters of the South Pacific gyre and ACC waters? 2) What fluxes of trace metals, especially Fe, are delivered by Pacific Deep Water to the Southern Ocean for upwelling to the surface waters? Are these fluxes hydrothermal or benthic in origin? Are dissolved metals supplied by the Pacific-Antarctic Ridge to the abyssal Southern Ocean? 3) How do micronutrient metal uptake stoichiometries change across gradients of primary production, community composition, and nutrient limitation from the gyre to ACC waters? How are these affected by metal speciation? 4) How do pre-formed biological signatures in surface waters, combined with regeneration and scavenging along the transport path, influence the regional and global distribution of TEIs?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（按定义上的数量非常低，对生命都是必不可少的，因此被认为是浮游植物生长的营养。其他元素对于追踪其他海洋过程可能很有用，而有些元素（例如铅）很重要，因为它们是污染物。该项目将解决三个主要目标：1）测量微量营养素，锰，锌，铜，铜，镉，镍和污染物的溶解浓度和尺寸分配，从大溪地向南极洲到南极，然后返回东北到南美； 2）分析铁，锌，锌，镉，镍和铜在海水中的同位比率的相对丰度，从本节中悬挂的颗粒，气溶胶和孔隙水中的同位素比，因为同位素可以通过诊断症状，而无需诊断诊断，而不是本节的诊断症状，而无需进行诊断。 3）使用海洋模型来限制海洋过程的速率以及海洋循环对痕量金属和同位素分布的影响。该项目涵盖了三个美国实验室，四名研究生和几个本科生将参加。它还将向其他几个合作小组提供超过滤样品和数据。太平洋深水带有水热输入，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。 The investigators will use a variety of analytical approaches, along with analyses made by other project collaborators, to address four major objectives related to dissolved micronutrient biogeochemistry in this region: 1) What are the relative fluxes of dissolved metals from dust, sediments, and Antarctic continental inputs to surface waters of the South Pacific gyre and ACC waters? 2）太平洋深水向南大洋传递了哪些痕量金属的通量，尤其是FE？这些磁通是原始的水热还是底栖？太平洋 - 北极山脊提供的溶解金属是否到南大洋？ 3）微量营养素的金属摄取量如何从回旋水到ACC水域的初级生产，社区组成和营养限制的梯度之间发生变化？这些如何受金属形成的影响？ 4）地表水中的预先形成的生物学特征，加上沿运输路径的再生和清理，影响TEI的区域和全球分布？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的审查标准通过评估来获得支持的。