Collaborative Research: Constrainging Water Mass Age and Particle Flux In The Arctic Ocean Using Pa-231 and TH-230 as Tracers

这是罗得岛大学和明尼苏达州双城大学的主要研究者之间的合作建议。 北冰洋比以前认为的更具动态性，其特点是生产力和相关颗粒通量的空间和季节变化大，河口输入和陆架水延伸到内部盆地的横向入侵，以及地形引导的边界流沿着盆地周边，导致区域极端的水团年龄。 主要研究人员假设，由横向平流和颗粒通量共同控制的“边界清除”在从北冰洋水体中去除颗粒反应性化学物质方面发挥着重要作用。 他们将评价边界清除的作用，因为它对碳向深海沃茨输出、包括污染物在内的活性化学品的沉积物积累以及这些化学品向大西洋输出等关键地球化学过程具有重要影响。 目标是在全流域范围内限制这些基本过程，并为这种知之甚少的极端环境开发预测性地球化学模型。主要研究人员将确定天然放射性核素Protactinium-231（231 Pa）- Thorium-230（231 Th）对是否可用作示踪剂，以提供现代和末次冰期北极流域范围内水团年龄和粒子通量的综合图像。主要研究人员将进行一项全面的研究，包括对来自水柱、沉积物收集器材料、表层沉积物和沉积物的溶解和颗粒样品进行231 Pa-231 Th配对分析。 这将有助于更好地了解颗粒组成的重要性，231 Pa-231 Th分馏通过量化悬浮颗粒物，沉积物捕集器材料和表层沉积物的化学成分。 由于大陆架与开阔洋的比例高、水团年龄和粒子通量的区域极端情况以及动态环流的综合影响，边界清除在北极应该是明显的。 这种环境设置是显着不同于其他海洋地区的Pa和Th示踪剂的研究已经进行，并提供了一个独特的机会，调查边界清除，反过来，限制一些悬而未决的问题，关于古应用231 Pa-231 Th。

Abstract OPP-0002313MoranOPP-0004029EdwardsThis is a collaborative proposal between Principal Investigators at the Universities of Rhode Island and Minnesota-Twin Cities. The Arctic Ocean is much more dynamic than previously believed, characterized by large spatial and seasonal variations in productivity and associated particle flux, significant estuarine input and lateral intrusions of shelf water extending into the interior basins, and topographically-steered boundary currents along the perimeters of basins that result in regional extremes in water mass age. The Principal Investigators hypothesize that "boundary scavenging", controlled by a combination of lateral advection and particle flux, plays a significant role in the removal of particle-reactive chemicals from the water column of the Arctic Ocean. They will evaluate the role of boundary scavenging as it has an important bearing on such key geochemical processes such as the export of carbon to deep waters, the sediment accumulation of reactive chemicals, including contaminants, and the export of these chemicals to the Atlantic. The objective is to constrain these fundamental processes on a basin-wide scale and to develop predictive biogeochemical models for this poorly understood and extreme environment. The Principal Investigators will determine whether that natural radionuclide Protactinium-231 (231Pa) - Thorium -230 (231Th) pair can be used as tracers to provide an integrated picture of water mass age and particle flux on a basin-wide scale in the modem and last glacial Arctic.To provide an increased understanding of the processes that control the redistribution of these tracers in the Arctic Ocean, the Principal Investigators will undertake a comprehensive study that includes paired 231Pa - 231Th analyses in dissolved and particulate samples from the water column, sediment trap material, surface sediments and sediment comes. This should help with a better understanding of the importance of particle composition on 231Pa - 231Th fractionation by quantifying the chemical composition of suspended particulate matter, sediment trap material and surface sediments. Boundary scavenging should be pronounced in the Arctic, due to the combined effects of the high ratio of shelf to open ocean, the regional extremes in water mass age and particle flux, and a dynamic circulation. This environmental setting is markedly different than other ocean regions where Pa and Th tracer studies have been conducted and provides a unique opportunity to investigate boundary scavenging and, in turn, constrain some outstanding questions regarding the paleo-application of 231Pa - 231Th.