Do interactions between vertically and horizontally transported particles measurably affect particle composition and flux to the sediments? A mechanistic approach.

许多元素从表层海洋向深海的输出是通过下沉颗粒的通量来调节的;例如，下沉颗粒占有机碳通过中层区垂直迁移的50-80%。颗粒有机碳（POC）在开阔海洋中的异养转化通常非常有效，因为在表面沃茨中产生的90%的POC在真光层中或在通过上层水柱的过程中返回到无机形式。然而，在表层沃茨中产生的一小部分有机物会在运输到深海或海底时幸存下来。同样，无机物质的通量和成分在向海底迁移的过程中也会发生变化。也许这种变化最明显的例子是碳酸盐和生物硅在通过水柱下沉时的溶解。然而，到达深海和沉积物的颗粒有机物和无机物的通量和组成不仅取决于它们在表层沃茨中的来源，而且还取决于垂直运输过程中发生的变化、补充和选择性去除。在某些区域，特别是靠近边缘的区域，横向迁移也可能很广泛。沉降物与悬浮颗粒或溶解有机物之间通过聚集/解聚和溶解/溶解的交换也会影响组成。在这个项目中，位于斯托尼布鲁克的纽约州立大学的一个研究小组着手对海洋进行更好的机械理解。在全球碳循环中的作用以及影响沉积记录的因素。他们的工作是围绕着五个相互关联的假设，围绕着颗粒沉降到海底时的矿化和交换，对沉降颗粒的潜在水平影响，以及垂直和水平运输如何潜在地影响沉积物记录的解释。他们将应用在最近的MedFlux计划中开发的一些工具，通过明确考虑压载矿物（包括天青石和重晶石）来产生更好的下沉通量定量模型，并更好地定义颗粒之间的相互作用。他们还将把用捕集器和泵取样的颗粒的无机、有机和放射化学分析结果与我们提议的百慕大海隆地点的底部沉积物的结果进行比较。虽然这是一项现代过程研究，但预计将具有重大的古海洋学意义。量化的相对垂直和水平通量的关键古海洋学代理相结合的表征的季节性通量将大大提高我们的理解现有的沉积物记录在百慕大隆起，提高质量的未来重建，以及导致更强大的解释从其他网站具有显着的横向输入。更广泛的影响。PI（有机地球化学，放射化学，古海洋学，建模）所代表的背景的多样性为培养下一代海洋科学家提供了独特的机会。四名研究生将参与该项目。所有人都将接受海上、实验室和现代数据分析方面的培训。除了研究生外，一名博士后学者将参与本项目，NSF无需额外费用。研究所还参与外展活动，包括向非专业人士和其他社区团体介绍研究成果。

The export of many elements from the surface ocean to the deep sea is mediated by the flux of sinking particles; for example, sinking particles account for 50-80% of the vertical transport of organic carbon through the mesopelagic zone. Heterotrophic remineralization of particulate organic carbon (POC) in the open ocean is usually very efficient, as 90% of the POC produced in surface waters is returned to inorganic form in the euphotic zone or during transit through the upper water column. However, a small fraction of the organic matter produced in surface waters survives transit to the deep ocean or seafloor. Similarly, the flux and composition of inorganic material also vary during transport to the sea floor. Perhaps the most obvious example of such modification is the dissolution of carbonate and biogenic silica as they sink through the water column. However, the flux and composition of particulate organic and inorganic matter that reaches the deep sea and sediments depend not just on their source in the surface waters, but also on alteration, supplementation, and selective removal that occurs during vertical transit. In some regions, particularly near margins, lateral transport can also be extensive. Exchange between sinking material and suspended particles or dissolved organic matter via aggregation/disaggregation and solution/dissolution can also influence composition. In this project, a research team at the State University of New York at Stony Brook set out to develop a better mechanistic understanding of the ocean?s role in the global carbon cycle and the factors that influence the sedimentary record. Their work is developed around five interrelated hypotheses revolving around the themes of remineralization and exchange as particles sink to the sea floor, potential horizontal influences on sinking particles, and how vertical and horizontal transport potentially influence the interpretation of the sediment record. They will apply some of the tools developed during the recent MedFlux program to produce better quantitative models of sinking fluxes by incorporating explicit consideration of ballast minerals (including celestite and barite) and to define better the interactions among particles as they sink. They will also compare results of inorganic, organic and radiochemical analyses of particles sampled by traps and pumps with those of bottom sediments at our proposed site on the Bermuda Rise. While this is a modern process study, it is expected to have significant paleoceanographic implications. Quantifying the relative vertical and horizontal fluxes of key paleoceanographic proxies in combination with characterization of the seasonal fluxes will greatly enhance our understanding of the existing sediment record at the Bermuda Rise, and improve the quality of future reconstructions as well as lead to more robust interpretations from other sites with significant lateral input. Broader Impacts. The diversity of backgrounds represented by the PIs (organic geochemistry, radiochemistry, palaeoceanography, modeling) offers unique opportunities to train the next generation of marine scientists. Four graduate students will be involved in this project. All will receive training at sea, in the laboratory, and in modern data analysis. In addition to graduate students, a postdoctoral scholar will be involved in the present project at no additional cost to NSF. The PIs also participate in outreach activities that will include presentations of research results to lay persons and other community groups.