Supply, eastward transport, and temporal variability of trace elements in the zonal current system of the tropical West Pacific - an integrated innovative study using Nd isotopes, rare earth elements, and ocean dynamics

热带西太平洋纬向流系统中微量元素的供应、东移和时间变化——一项利用 Nd 同位素、稀土元素和海洋动力学的综合创新研究

• 批准号: 396302194
• 负责人: Dr. Melanie Behrens
• 金额: --
• 依托单位: Oberservatoire Midi-Pyrennees
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/396302194?language=en
• 关键词: Supply; eastward; transport; temporal; variability

The study is aimed at testing the potentially crucial role of the tropical Pacific zonal current system in providing trace elements (TE) (incl. micronutrients) from the West Pacific source area to the iron-limited East Pacific, with a particular focus on recently discovered mid-depth jets (>1000 m water depth). The main aim is to resolve their origin, spatial extent, and geochemical composition to evaluate their potential role in fuelling productivity in the East Pacific. Integrated into previous and ongoing geochemical and physical oceanographic studies of the South, West, and equatorial Pacific (own projects and those of my partners), the study will also address the temporal variability of TE supply and eastward transport. The tropical West Pacific is thought to be an important source area of micronutrients and other TEs to eastward flowing zonal currents that transport them to the iron-limited East Pacific, and thus sustain primary productivity and hence ecosystems and fisheries in this area. It is therefore imperative to understand the TE supply to the West Pacific, the origin and structure of the currents transporting them, and their possible inter-annual variability. Particularly, it is currently not known, whether TE supply occurs only to the surface and subsurface currents or also to the mid-depth jets, and whether all island margins in the West are equally important TE sources. Moreover, it is not yet clear, whether the mid-depth jets originate in the West as discrete jets transporting TEs to the East, or whether they are fed by recirculation from other currents, in which case they would take in a less important role in the eastward transport of TEs including micronutrients. Neodymium (Nd) isotopes and rare earth elements (REE) are ideally suited to identify the source and trace the transport of TEs in the tropical Pacific due to their non-bioactive nature and their distinct West and East Pacific signatures. In close collaboration with my German and French partners, experienced geochemists and physical oceanographers, I propose to combine new, high-resolution and existing Nd isotope and REE data from the tropical West Pacific with extensive physical oceanographic data from the same cruises and with additional trace metal data (Fe, Zn, Cu, Cd, Mn, Al) that are published or will soon become available. This multidisciplinary approach will provide insight into element (incl. micronutrient) sources, supply, transport, and dynamics in the tropical Pacific. The proposed study and concerted effort in data interpretation with German and French experts represents the most comprehensive approach to understand the physical and chemical oceanography of the tropical West Pacific to date and is expected to uniquely address the above-mentioned open questions.

这项研究旨在测试热带太平洋纬向流系统在提供微量元素(TE)方面的潜在关键作用(包括。从西太平洋污染源区域到铁有限的东太平洋的微营养素)，特别侧重于最近发现的中深喷流(&gt；1000米水深)。主要目的是确定它们的来源、空间范围和地球化学组成，以评估它们在东太平洋促进生产力方面的潜在作用。结合以往和正在进行的对南太平洋、西太平洋和赤道太平洋的地球化学和物理海洋学研究(我自己和我的合作伙伴的项目)，这项研究还将讨论TE供应和向东输送的时间变异性。热带西太平洋被认为是向东流动的纬向流输送微量营养素和其他TES的重要来源地区，将其输送到铁有限的东太平洋，从而维持该地区的初级生产力，从而维持该地区的生态系统和渔业。因此，必须了解西太平洋的TE供应、输送它们的洋流的来源和结构，以及它们可能的年际变化。特别是，目前尚不清楚TE供应是仅发生在表层和次表层洋流，还是也发生在中深度急流，以及西部的所有岛屿边缘是否都是同样重要的TE来源。此外，尚不清楚中深度急流是起源于西方的离散急流，还是来自其他洋流的再循环，在这种情况下，它们在向东输送包括微量营养素在内的硫化物的过程中将发挥较不重要的作用。由于其非生物活性的性质以及其独特的西太平洋和东太平洋特征，钕(ND)同位素和稀土元素(REE)非常适合于确定热带太平洋中TES的来源和运输。我同我的德国和法国伙伴、经验丰富的地球化学家和物理海洋学家密切协作，提议将热带西太平洋新的、高分辨率和现有的ND同位素和REE数据与来自相同邮轮的广泛物理海洋学数据结合起来，并与已经出版或即将推出的其他痕量金属数据(Fe、Zn、Cu、Cd、Mn、Al)结合起来。这种多学科方法将提供对要素(包括微营养素)热带太平洋的来源、供应、运输和动态。拟议的研究以及与德国和法国专家在数据解释方面的协调努力是迄今为止了解热带西太平洋物理和化学海洋学的最全面的方法，预计将独特地解决上述悬而未决的问题。