GEOTRACES Peru-Tahiti section: Measurement of 7Be as a Tracer of Upper Ocean Processes

GEOTRACES 秘鲁-塔希提岛部分：测量 7Be 作为上层海洋过程的示踪剂

• 批准号: 1451120
• 负责人: David Kadko
• 金额: $ 32.06万
• 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: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2017-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1451120&HistoricalAwards=false
• 关键词: GEOTRACES; Peru; Tahiti; section; Measurement

In the ocean, trace elements function variously as nutrients, as contaminants from human activity, and even as convenient tracers of current and past oceanographic processes. Their biogeochemical cycling has major impacts on the ocean carbon cycle and ecosystem dynamics as well as on global climate change. Many processes influencing the distribution and behavior of trace elements in the ocean cannot be directly observed, so consequently a variety of geochemical tracers are used to provide important constraints on their rates and pathways. Beryllium-7 (Be7) is a cosmogenic (i.e., produced in the upper atmosphere) radionuclide that, because of its half-life (53.3d), can be used in the study of environmental processes occurring over seasonal timescales. This timescale is important to studies of biological production, nutrient regeneration, and atmospheric deposition, to name a few. In this project, a research team from the University of Miami will make measurements of water column Be7 along the U.S.GEOTRACES transect from Peru to Tahiti in 2013. The mission of the International GEOTRACES Program (of which the US program is a component) is "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." As part of the multi-institutional U.S.GEOTRACES Pacific campaign, the Miami team will address key tasks formulated within the GEOTRACES Science Plan. Specifically, they will: (1) provide realistic estimates of the underlying transport processes influencing measured trace elements of interest (TEI) distributions; they will use water column measurements of Be7 as a tracer of physical processes, such as mixing and upwelling, which redistribute biologically active species; and (2) develop and apply new Be7 methods for quantifying the atmospheric deposition of TEIs measured by other research teams participating in the campaign. Measurements of Be7 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 aerosol deposition models and the atmospheric input of trace elements. Broader impacts: The proposed work is in support of the GEOTRACES program, and as such contributes to many of the broad intellectual objectives of that program. The ability to provide estimates of the atmospheric input of relevant TEIs is an important example, and one that will contribute widely to the field in the future beyond GEOTRACES, including understanding anthropogenic impacts on the oceans. Education and training of graduate students will be essential components of this research.

在海洋中，痕量元素作为营养，作为人类活动的污染物，甚至是当前和过去海洋学过程的方便示踪剂。他们的生物地球化学循环对海洋碳循环和生态系统动态以及全球气候变化产生了重大影响。 无法直接观察到影响海洋中痕量元素的分布和行为的许多过程，因此，使用各种地球化学示踪剂来对其速率和途径提供重要的约束。铍-7（BE7）是一种宇宙基因（即在大气层中产生的）放射性核素，由于其半衰期（53.3d），可用于研究在季节性时间表上发生的环境过程。这个时间尺度对于研究生物生产，营养再生和大气沉积的研究很重要。在这个项目中，迈阿密大学的一个研究团队将在2013年从秘鲁到大溪地的水柱BE7进行测量。国际地理位置计划的任务（美国计划是一个组件）的任务是“识别流程并量化范围的范围，以控制关键的痕量分布环境中的环境和各种环境的分布，从而使它们在海洋和iSSOPES中进行了变化。作为多机构的Usegotraces Pacific运动的一部分，迈阿密团队将解决在Geotraces科学计划中制定的关键任务。 具体而言，它们将：（1）提供影响影响的痕量元素（TEI）分布的基本运输过程的现实估计；他们将使用BE7的水柱测量作为物理过程的示踪剂，例如混合和上升流，这些过程重新分布生物学活性物种。 （2）开发并应用新的BE7方法来量化由参与活动的其他研究团队衡量的TEI的大气沉积。地表水中BE7和沿巡航轨道的低大气中的测量将提供相关TEI的大气输入的估计。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。这项工作中生成的数据将可用，以允许气溶胶沉积模型的地面桥接和痕量元素的大气输入。更广泛的影响：拟议的工作是支持Geotraces计划的，因此有助于该计划的许多广泛的知识目标。提供相关TEI的大气输入的估计的能力是一个重要的例子，它将在未来的地理位置之外对该领域进行广泛贡献，包括了解人为对海洋的影响。研究生的教育和培训将是这项研究的重要组成部分。