Collaborative Research: US GEOTRACES GP17-OCE: Shipboard Measurements of Dissolved Aluminum, Iron, and Manganese – Tracing Inputs to the South Pacific Gyre and Southern Ocean

国际研究计划GEOTRACES的目标是了解海洋中微量化学元素及其同位素的分布。微量元素在海洋中的重要性在于它们作为海洋浮游植物（例如，铁），作为毒物（例如，铅），以及作为过去和现在海洋过程的示踪剂（例如，钍）。在该项目中，将测量在东南太平洋和邻近的南大洋进行研究航行期间收集的海水样本中两种微量营养素微量元素（铁和锰）和一种大气尘埃沉积示踪物（铝）的溶解浓度，以便更好地了解这些微量营养素的投入及其对这些区域生物过程的影响。 化学分析将在海上近实时进行，从而提供第一次数据一瞥，为巡航取样战略和其他调查人员进行的分析提供信息。该项目涉及两个美国实验室，并将支持研究生和本科生的研究。美国GEOTRACES GP17-OCE考察将侧重于沿沿着一条穿越南太平洋环流和南大洋太平洋部分的断面的微量元素和同位素分布，在该断面，向表层海洋供应溶解铁（DFe）和锰（DMn）被认为调节初级生产和相关的碳和营养元素循环。调查人员将在船上和巡航后测量溶解铝（DAl）、DFe和DMn，以限制（1）该海洋区域的尘埃沉积量以及DAl和DMn作为风成铁输入示踪剂的保真度;（2）深海DAl和DFe异常的起源及其对这些元素的深层来源的影响;深海热液DFe排放的来源和归宿及其在支持南大洋初级生产中的作用。项目结果，由GP17-OCE合作者对其他痕量化学物质的测量补充，将促进对控制海洋DAl，DFe和DMn的清单和分布的过程及其未来变化轨迹的理解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The goal of the international research program GEOTRACES is to understand the distributions of trace chemical elements and their isotopes in the oceans. The importance of trace elements in the ocean lies in their roles as essential micronutrients for marine phytoplankton (e.g., iron), as toxicants (e.g., lead), and as tracers of past and present oceanic processes (e.g., thorium). In this project, the dissolved concentrations of two micronutrient trace elements (iron and manganese) and a tracer of atmospheric dust deposition (aluminum) will be measured in seawater samples collected during a research cruise in the southeastern Pacific Ocean and adjacent Southern Ocean, in order to better understand the inputs of these micronutrients and their impact on biological processes in these regions. Chemical analyses will be performed at sea in near real-time, thus providing a first glimpse of data that will inform the cruise sampling strategy and the analyses performed by other investigators. The project involves two US laboratories, and will support the research of a graduate and undergraduate student. The U.S. GEOTRACES GP17-OCE expedition will focus on the distribution of trace elements and isotopes along a transect crossing the South Pacific Gyre and the Pacific sector of the Southern Ocean, where the supply of dissolved iron (DFe) and manganese (DMn) to the surface ocean is thought to regulate primary production and associated cycling of carbon and nutrient elements. The investigators will undertake shipboard and post-cruise measurements of dissolved aluminum (DAl), DFe and DMn in order to constrain (1) the magnitude of dust deposition to this ocean region and the fidelity of DAl and DMn as tracers of aeolian iron inputs; (2) the origin of deep-ocean DAl and DFe anomalies, and their implications for deep sources of these elements; and (3) the source and fate of hydrothermal DFe emissions from the deep ocean and their role in supporting Southern Ocean primary production. Project results, complemented by measurements of other trace chemical species made by collaborators on GP17-OCE, will advance the understanding of the processes that control the oceanic inventories and distributions of DAl, DFe and DMn, and their trajectories of future change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.