Collaborative Research: US GEOTRACES Arctic Section - Water mass composition, circulation and mean residence times derived from measurements of natural and manmade tracers

合作研究：美国 GEOTRACES 北极部分 - 根据天然和人造示踪剂的测量得出的水体成分、循环和平均停留时间

• 批准号: 1436125
• 负责人: David Ho
• 金额: $ 23.33万
• 依托单位: University of Hawaii
• 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: 2015-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1436125&HistoricalAwards=false
• 关键词: Collaborative; Research; US; GEOTRACES; Arctic

In this project, investigators participating in the 2015 U.S. GEOTRACES Arctic expedition will measure six oceanic tracers in order to better understand oceanic water movement in the Arctic Ocean. With this information in-hand, it will be much easier for other investigators to interpret their own seawater chemistry data. In common with other national 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. Some trace elements are essential to life, others are known biological toxins, and still others are important because they can be used as tracers of a variety of physical, chemical, and biological processes in the sea. The tracers to be measured as part of this study have proven their value for studies of water mass composition, circulation, and mean residence times on short to long time scales. This project will also provide training for two high school teachers, and develop curriculum for high school students.The Arctic is presently undergoing system-scale environmental change at a pace not seen elsewhere on the globe. Thus, it is essential to establish a baseline of the distributions of trace elements and isotopes (TEIs) for future reference and to begin understanding the processes that determine the TEI distributions in the Arctic Ocean. Particularly with respect to the receding sea ice cover, it is imperative to understand how TEIs impact vital functions of the Arctic system, such as primary productivity or, more generally, the cycling of carbon under these rapidly changing environmental conditions. To further understanding on water movement and thus trace element distributions in the Arctic, this team of researchers will measure chlorofluorocarbons (CFCs), sulfur hexafluoride (SF6), tritium, helium isotopes, stable isotopes of water and C-14 along the transect. These tracers have been used successfully in past studies for determination of water mass composition, circulation pathways, and mean residence times on time scales from less than one year (CFCs/SF6 and tritium/He-3) to several hundred years (C-14). The researchers plan to make underway measurements of the saturations of CFCs and SF6 in partially and totally ice covered waters along the cruise track, and will also calculate forward and backward sea ice trajectories at all station locations to determine sources of sea ice samples. These trajectories will be used as a first step towards understanding the pathways of waters in the surface mixed layer.

在该项目中，参加2015年美国地理探险队的调查人员将测量六个海洋示踪剂，以便更好地了解北极海洋中的海洋水运动。 借助此信息，其他研究人员可以更容易解释自己的海水化学数据。 美国北极探险队的目标是与国际地理计划计划中的其他国家倡议共同确定过程，并量化控制海洋中关键的微量元素和同位素分布的通量，并确定这些分布对改变环境条件的敏感性。一些痕量元素对生命至关重要，另一些是已知的生物毒素，而另一些则很重要，因为它们可以用作海洋中各种物理，化学和生物过程的示踪剂。作为这项研究的一部分，要测量的示踪剂证明了它们在短到长时间的水质量组成，循环和平均停留时间的研究中的价值。该项目还将为两名高中教师提供培训，并为高中生开发课程。目前，北极正在经历系统规模的环境变化，其速度在全球其他地方都看不到。因此，必须建立痕量要素和同位素（TEI）的分布的基准，以便将来参考，并开始理解确定北极海洋中TEI分布的过程。特别是关于退化的海冰覆盖，必须了解TEI如何影响北极系统的重要功能，例如主要生产力，或者更一般而言，在这些快速变化的环境条件下碳循环。为了进一步了解北极的水运动以及痕量元素分布，该研究人员将测量氯氟甲苯（CFCS），硫六氟化硫（SF6），tritium，Tritium，氦同位素，稳定的稳定的水和C-14同位素。这些示踪剂已成功地用于过去的研究中，以确定水量组成，循环途径和平均停留时间，从不到一年（CFCS/SF6和Tritium/He-3）到数百年（C-14）。研究人员计划在沿巡航轨道的部分和完全覆盖的水域中对CFC和SF6的饱和度进行测量，还将计算所有站点位置的前后海冰轨迹，以确定海冰样品的来源。这些轨迹将被用作理解表面混合层中水路的第一步。