Collaborative Research: US GEOTRACES Pacific Section-Shipboard Al, Mn and Fe

2013年GEOTRACES东太平洋带状样带巡航将从秘鲁沿海的高产上升流区到南太平洋亚热带环流的分层少营养水域，然后前往塔希提岛。将遇到一系列地下缺氧水和来自秘鲁边缘的沉积输入，以及东太平洋隆起（EPR） 15°S的热液喷口。华盛顿大学和老道明大学的科学家们计划分析海水样品中水柱样品中溶解的和完全溶解的铝（Al）、锰（Mn）和铁（Fe）。船上将分析上层水柱（1000米深度）中溶解的Al， Mn和Fe样品，以确保收集的样品未受污染，以及EPR西部热液羽深度的样品。船上的分析将通过岸上对所有深度的水柱样本的分析，以及对总可溶性铝、锰和铁的分析来增强，这将补充其他GEOTRACES调查人员对颗粒金属的直接分析。研究结果将用于检验以下关于海洋中铝、锰和铁的来源和循环的假设：(1)当风成输入相对恒定时，地表水中溶解的铝浓度随生物生产而变化；(2)东太平洋氧最小带地下水中溶解Al、Mn和Fe的浓度最大值是大陆边缘通过再悬浮和再活化的方式进行横向输送的结果；(3)在东太平洋隆起脊顶附近的中性浮力羽流中，溶解的铁和铝将遇到具有保守行为的环境水平值。至于更广泛的影响，研究结果将通过讲座、互联网和新闻稿向公众传播。作为该项目的一部分，华盛顿大学的一名研究生和一名本科生将得到支持和培训。

The 2013 GEOTRACES Eastern Pacific Zonal transect cruise will transit from the highly productive coastal upwelling region off Peru to the stratified oligotrophic waters of the South Pacific subtropical gyre on its way to Tahiti. A range of subsurface oxygen depleted water and sedimentary inputs from the Peru margin will be encountered, as well as hydrothermal vents at 15°S on the East Pacific Rise (EPR). Scientists from the University of Washington and Old Dominion University plan to analyze seawater samples for dissolved and total-dissolvable aluminum (Al), manganese (Mn), and iron (Fe) in water column samples. The dissolved Al, Mn, and Fe in samples from the upper water column (1000 m depth) will be analyzed onboard to ensure samples being collected are uncontaminated, as well as samples from west of the EPR at hydrothermal plume depths. The shipboard analyses will be augmented by shore-based analyses of water column samples from all depths, as well as analyses of total-dissolvable Al, Mn, and Fe, which will complement the direct analyses of particulate metals undertaken by other GEOTRACES investigators. Results will be used to test the following hypotheses concerning the sources and cycling of Al, Mn and Fe in the ocean: (1) when Aeolian inputs are relatively constant, dissolved Al concentrations in surface waters vary as a function of biological production; (2) concentration maxima of dissolved Al, Mn, and Fe in subsurface waters of the Eastern Pacific oxygen minimum zone are the result of lateral transport from the continental margin by means of resuspension and remobilization; and (3) values about ambient levels with conservative behavior will be encountered in the neutrally buoyant plume about the East Pacific Rise ridge crest for dissolved Fe and Al. As regards broader impacts, results from the study would be disseminated to the public via lectures, the internet, and press releases. One graduate and one undergraduate student from the University of Washington would be supported and trained as part of this project.