GEOTRACES - Intercalibration Studies of Short-lived U/Th Series Isotopes and Marine Particles

GEOTRACES - 短寿命 U/Th 系列同位素和海洋粒子的相互校准研究

• 批准号: 0726319
• 负责人: Ken Buesseler
• 金额: $ 23.71万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-10-01 至 2009-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0726319&HistoricalAwards=false
• 关键词: GEOTRACES; Intercalibration; Studies; Short; lived

During the next ten to twelve years, scientists from oceanographic laboratories around the world will participate in GEOTRACES -- a benchmark effort to investigate the distribution and behavior of chemicals in the sea that can give insight into the way the ocean works as a geophysical system. With funding from this grant, scientists at the Woods Hole Oceanographic Institution will participate in a pair of GEOTRACES intercalibration cruises in 2008 and 2009. They will focus their efforts on understanding the physical and chemical principles governing the spatial and temporal distributions of radioisotopes in the natural Uranium-Thorium decay series. U-Th tracers are likely to be vital to the interpretation of key GEOTRACES trace elements that are particle- reactive and bioactive. Essentially, thorium isotopes will provide direct information on the vertical fluxes and remineralization rates on time scales of days/weeks (234Th t ½ = 24.1 d) up to several years (228Th t ½ = 1.91 yr), while 228Ra (t ½ = 5.75 y) is a tracer of horizontal transport from basin margins to the interior on time scales of months to years. The investigators contend that these effects, i.e. surface scavenging and remineralization as well as horizontal transport of suspended particles far from ocean boundaries, are important in setting the distributions of many trace elements that will be measured in GEOTRACES, and important for understanding oceanic processes in their own right. Specifically, the Woods Hole group will: 1) participate with other GEOTRACES scientists in the general particulate trace element intercalibration efforts comparing in-situ vs. bottle vs. deck based sampling methods and making basic filter and operational comparisons appropriate for a wider suite of particle reactive trace elements for distribution to the scientific community; 2) organize and lead distribution of particulate 234Th and 238Th for intercalibration among that community; and 3) work on a novel set of sampling and analytical methods to improve accuracy and reduce water requirements for this suite of Th and Ra isotopes. In terms of broader impacts, it is clear that this effort will benefit oceanographic research activites well beyond GEOTRACES inasmuch as new practical and theoretical knowledge about sampling and analytical methodologies will be obtained. The project will also involve significant inter-institutional collaboration, both within the US and internationally, as marine radiochemists around the world will have the opportunity to participate in analytical intercalibration activities.

在接下来的十到十二年里，来自世界各地海洋学实验室的科学家将参与 GEOTRACES，这是一项研究海洋中化学物质分布和行为的基准项目，可以深入了解海洋作为地球物理系统的运作方式。 在这笔赠款的资助下，伍兹霍尔海洋研究所的科学家将参加 2008 年和 2009 年的两次 GEOTRACES 相互校准航行。他们将集中精力了解控制天然铀-钍衰变系列中放射性同位素时空分布的物理和化学原理。 U-Th 示踪剂可能对于解释具有颗粒反应性和生物活性的关键 GEOTRACES 微量元素至关重要。本质上，钍同位素将提供有关天/周（234Th t 1/2 = 24.1 d）至数年（228Th t 1/2 = 1.91 y）时间尺度上的垂直通量和再矿化速率的直接信息，而228Ra（t 1/2 = 5.75 y）是在数月至数年的时间尺度上从盆地边缘到内部的水平迁移的示踪剂。研究人员认为，这些效应，即表面清除和再矿化以及远离海洋边界的悬浮颗粒的水平运输，对于确定将在 GEOTRACES 中测量的许多微量元素的分布非常重要，对于理解海洋过程本身也很重要。具体来说，Woods Hole 小组将： 1) 与其他 GEOTRACES 科学家一起参与一般颗粒微量元素相互校准工作，比较原位、瓶子和甲板采样方法，并对更广泛的颗粒反应微量元素进行基本过滤和操作比较，以便分发给科学界； 2) 组织和领导颗粒物 234Th 和 238Th 的分配，以便在该社区之间进行相互校准； 3) 研究一套新颖的采样和分析方法，以提高这套 Th 和 Ra 同位素的准确性并减少对水的需求。就更广泛的影响而言，很明显，这项工作将有利于海洋学研究活动，远远超出 GEOTRACES 的范围，因为将获得有关采样和分析方法的新的实践和理论知识。 该项目还将涉及美国国内和国际上的重要机构间合作，因为世界各地的海洋放射化学家将有机会参与分析相互校准活动。