Collaborative Research: GEOTRACES - 210Po and 210Pb distribution at Eastern Pacific Interface Regimes

2013年，一个由美国海洋化学家和地球化学家组成的多机构团队将发起一次前往太平洋的大型探险，作为国际地球物理研究计划的一部分，绘制和研究微量元素和同位素的分布。由于天然U-Th放射性核素系列中的放射性子体同位素作为海洋沉积动力学和水动力学的天然示踪剂已被证明具有价值，因此对所有地球物理研究人员都将具有巨大的价值。特别是，自然产生的Pb210/Po210放射性同位素对将有助于量化美国地质调查局太平洋行动中感兴趣的其他微量元素和同位素的颗粒清除速率。这是因为这两种同位素本身就是粒子反应性和放射性的，因此为跟踪其他粒子反应性物质的垂直运输提供了一个自然时钟。在这个项目中，韦恩州立大学和纽约大学皇后学院的研究人员将沿着美国地质调查局东南太平洋部分对数百个溶解和颗粒(大大小小)的210Po和210Pb样本进行采样和分析。大约三分之二的样本将集中在六个所谓的“超级站点”(选择进行密集研究的地点)，一半在主温跃层之上，另一半在海底云状层(海底上方几米长的悬浮物区域)。深度将根据区域大气输入、生态系统选择，并与船上其他研究人员的采样协调。另外三分之一将在东太平洋隆起附近的热液烟柱内进行。数据将根据界面清除模型按颗粒类型(例如细小/胶体、致石和生源)合成。因此，拟议的工作将与在活动期间资助用于研究其他粒子反应性或溶解的微量元素和放射性核素的其他美国地球物理研究机构的工作密切协调。广泛的影响：更广泛的影响与地球物理研究计划的整体密切相关：(1)通过提供广泛的可用于生物地球化学清除模型的210Po和210Pb数据来加强研究基础设施，(2)指导研究生和本科生的教育，以拟议的研究为例进行教学，(3)对地球科学感兴趣的未被充分代表的学生参与研究，(4)对海洋放射性化学、放射性化学的毕业生进行研究培训以及5)通过出版物、演示文稿和韦恩州立大学专门的公共网站公开传播成果。

In 2013, a multi-institutional team of U.S. marine chemists and geochemists will launch a major expedition to the Pacific Ocean to map and study the distribution of trace elements and isotopes as part of the International GEOTRACES Program. Because of their proven value as natural tracers of both sedimentation dynamics and hydrodynamics in the sea, radioactive daughter isotopes in the natural U-Th radionuclide series will be of immense value to all GEOTRACES researchers. In particular the naturally-occurring Pb210/Po210 radioisotope pair would be useful for quantifying rates of particulate scavenging of other trace elements and isotopes of interest in the U.S.GEOTRACES Pacific campaign. This is because these two isotopes are themselves particle-reactive and radioactive, thus providing a natural clock for tracking the vertical transport of other particle-reactive substances.In this project, researchers at Wayne State University and CUNY Queens College will sample and analyze several hundred dissolved and particulate (large and small) samples for 210Po and 210Pb along the U.S.GEOTRACES Eastern South Pacific section. About two thirds of the samples will be focused at six so-called "super stations" (sites chosen for intensive study), half above the main thermocline and the other half down across the benthic nepheloid layer (the zone of suspended material extending several meters above the seafloor). The depths will be chosen according to regional atmospheric input, ecosystems, and coordinated with sampling by other researchers onboard. The other third will be taken within the hydrothermal plume in the vicinity of the East Pacific Rise. The data will be synthesized according to interface scavenging models by particle types (e.g. fine/colloidal, lithogenic and biogenic). As such, the proposed work will be closely coordinated with that of other U.S.GEOTRACES PIs funded to study other particle-reactive or dissolved trace elements and radionuclide isotopes during the campaign.BROADER IMPACTS: The broader impacts are closely linked to those of the GEOTRACES Program as a whole: to enhance (1) research infrastructure by providing a broad array of 210Po and 210Pb data useful for biogeochemical scavenging models, (2) education by mentoring graduate and undergraduate students, teaching by example from proposed research, (3) participation of under-represented students interested in careers in the geosciences, (4) research training of graduates in marine radiochemistry, and 5) public dissemination of results through publications, presentations, and on a dedicated public website at Wayne State University.