GEOTRACES Pacific Meridional Transect: Measurement of Beryllium-7 as a Tracer of Upper Ocean Processes

GEOTRACES 太平洋经线横断面：测量铍 7 作为上层海洋过程的示踪剂

• 批准号: 1736319
• 负责人: Mark Stephens
• 金额: $ 41.03万
• 依托单位: Florida International University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1736319&HistoricalAwards=false
• 关键词: GEOTRACES; Pacific; Meridional; Transect; Measurement

The goal of the international GEOTRACES program is to understand the distributions of trace chemical elements and their isotopes in the oceans. One of the stated goals in the GEOTRACES Science Plan is to "create a unique opportunity for exploration and discovery by determining the distributions of novel trace elements and isotopes (TEIs) that have received little attention to date." This is a proposal to make measurements of one such species, the radioactive isotope beryllium-7 which will provide important biogeochemical rate information pertinent to the TEIs that will be measured during the 2018 U.S. GEOTRACES Pacific Meridional transect from Tahiti to Alaska. Many processes in the ocean cannot be directly observed and as such, tracers are used to provide important constraints on their rates and pathways. Beryllium-7 is a tracer that, because of its half-life (53.3 days), allows the study of processes which occur over time scales and depth scales that are otherwise difficult to obtain but which are critically important to studies of biological production, nutrient regeneration, and atmospheric deposition, to name a few. Advances in sampling and analytical techniques, coupled with a better understanding of the behavior of Be-7 in ocean biogeochemical cycles, present an opportunity to fully utilize this tracer.The proposed work has three main components:1) Measurements of Be-7 in the surface waters and in the lower atmosphere along the cruise track will provide estimates of the atmospheric input of relevant TEIs. The atmospheric input into the global ocean is an important budgetary component of numerous chemical species, yet is very difficult to constrain. The data generated in this work will be available to allow ground-truthing of models of aerosol deposition and atmospheric input of trace elements.2) Water column measurements of Be-7 provide a tracer of physical processes, such as mixing and upwelling, which redistribute biologically active species. Given quantitative knowledge of the circulation, mixing and ventilation of the water masses within which TEIs reside allows an assessment of the time- and space-integrated in situ biogeochemical behavior of these elements.3) The rate of oxygen utilization within the upper thermocline will be determined by water column measurements of Be-7 coupled with collected hydrographic data and observed oxygen distributions. The seasonal timescale afforded by Be-7 is ideal for estimating OUR within the shallow water just beneath the euphotic zone, where the most significant C remineralization is occurring. The project will support undergraduate student researchers at Florida International University, a leading minority serving institution. Lead investigator Kadko will participate in the Nippon Foundation - Partnership for Observation of the Global Oceans Center of Excellence (NF-POGO CofE), a unique platform which aims to provide world class training programs for students from emerging countries. Kadko will be offering an advanced topic course in chemical oceanography to these students during a stay at the Alfred Wegener Institute of Polar Studies. This outreach effort is consistent with the capacity building and educational goals of GEOTRACES as well as promoting international collaboration.

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。 Geotraces科学计划中既定的目标之一是“通过确定迄今为止很少关注的新颖痕量元素和同位素（TEIS）的分布来创造一个独特的探索和发现机会。”这是对一个这样一种物种进行测量的提议，即放射性同位素铍7，该物种将提供与TEI有关的重要生物地球化学率信息，该信息将在2018年美国地理品种从大塔希族人到阿拉斯加的Pacific Paciforations Pacifory Paciforations Paciforations Paciforations pactrect中进行测量。无法直接观察到海洋中的许多过程，因此，示踪剂用于对其速率和途径的重要限制。 Beryllium-7是一种示踪剂，由于其半衰期（53.3天），它允许研究随时间尺度和深度尺度进行的过程，这些过程原本难以获得，但对于生物生产，营养再生和大气沉积的研究至关重要，仅举几例。采样和分析技术的进步，加上对海洋生物地球化学循环中BE-7的行为的更好理解，这是一个充分利用此示踪剂的机会。拟议的工作具有三个主要组成部分：1）测量BE-7在地表水中和较低的大气层中沿着较低的大气中的估计估算的估计值相关估计的估计值，这是相关的大气级别的。进入全球海洋的大气输入是许多化学物种的重要预算组成部分，但很难约束。这项工作中产生的数据将可用，以允许在痕量元素的气溶胶沉积模型和大气输入模型中进行地面锻炼。2）BE-7的水柱测量值提供了物理过程的示踪剂，例如混合和上升的生物学生物学活性物种。给定对TEIS居住的水质量的循环，混合和通风的定量知识，可以评估这些元素的原位生物地球化学行为。 BE-7提供的季节性时间尺度是估算我们在舒适区下方的浅水中的理想选择，那里发生了最重要的C回忆。该项目将支持佛罗里达国际大学的本科生研究人员，佛罗里达国际大学是一家领先的少数民族服务机构。首席研究员Kadko将参加Nippon基金会 - 观察全球卓越中心（NF -POGO COFE）的合作伙伴关系，这是一个独特的平台，旨在为来自新兴国家的学生提供世界一流的培训计划。在阿尔弗雷德·韦格纳（Alfred Wegener）极地研究学院逗留期间，Kadko将向这些学生提供化学海洋学的高级主题课程。这种宣传工作与地理位置的能力建设和教育目标以及促进国际合作是一致的。

项目成果

Quantifying Atmospheric Trace Element Deposition Over the Ocean on a Global Scale With Satellite Rainfall Products

• DOI: 10.1029/2019gl086357
• 发表时间: 2019-12
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: D. Kadko;W. Landing;C. Buck