A Sediment Trap Study to Determine if the Flux of Silver to the Seafloor is Related to Export Productivity

学术价值：自20世纪80年代初S开展工作以来，人们越来越有兴趣提高我们对银颗粒通量与海洋出口生产率之间关系的理解。尽管沉积银与有机碳、蛋白石和生物成因钡等更传统的古替代物之间存在诱人的正相关关系，但还没有开展一项全面的研究来详细评估微粒银通量与海洋出口生产力之间的关系。如果银的下沉通量能够可靠地跟踪出口生产力，正如本研究将评估的那样，那么地球化学界将有一个新的示踪剂，为过去古生产力的变化提供重要的新见解和约束。特别是，该项目将检验关于银可用于追踪从表层海洋输出到沉积物的生物微粒有机物质通量的假设；此外，该项目将评估银作为过去生产力变化的替代示踪剂的潜在用途。第二个目标是确定沉积氧化还原条件是否影响沉积物中银的积累。这项工作将通过分析一套存档的沉积物捕捉器和从一系列海洋地点收集的沉积物样品中的银来完成。这项研究获得的数据将有助于开发一种新的古生产力替代指标(Ag)，该指标可用于改进古海洋重建。更广泛的影响：关于更广泛的影响，这项研究将使科学界更好地了解对海洋生物有害的元素银的生物地球化学循环，以及对氧化还原反应敏感的痕量金属的循环。这项研究将支持一名早期科学家，并为一名研究生和两名本科生提供培训。

Intellectual Merit: Since work conducted in the early 1980's, there has been a growing interest in improving our understanding of the relationship between the particle flux of Ag and export productivity in the ocean. Despite tantalizing positive correlations between sedimentary Ag and more traditional paleoproxies, such as organic carbon, opal and biogenic Ba, there has yet to be a comprehensive study undertaken to evaluate in detail the relationship between the flux of particulate Ag and export productivity in the ocean. If the sinking flux of Ag can be shown to reliably track export productivity, as will be evaluated in this study, then the geochemical community will have a new tracer to provide important new insights and constraints on past changes in paleoproductivity. In particular, this project will test the hypothesis that Ag can be used to trace the flux of biogenic particulate organic matter exported from the surface ocean to the sediments; furthermore, this project will evaluate the potential use of Ag as a proxy tracer of past changes in productivity. A secondary objective is to determine whether sedimentary redox conditions affect the accumulation of Ag in sediments. This work will be accomplished by analysis of Ag in a suite of archived sediment trap and sediment samples collected from a range of oceanographic locations. The data obtained from this research will aid in the development of a new paleoproductivity proxy (Ag) that can be utilized to improve paleoceanographic reconstructions. Broader Impacts: In regards to broader impacts, this research will provide the scientific community with a better understanding of the biogeochemical cycling of Ag, an element that is toxic to marine organisms, as well as the cycling of redox-sensitive trace metals. The study will support an early scientist, and provide training for one graduate student and two undergraduate students.