Oceanographic Testing and Verification of an Iron-Selective Electrode

海水中有效铁(Fe)的缺乏被广泛认为是限制广泛的高营养、低叶绿素(HNLC)海洋区域以及一些沿海上升流区浮游植物生长的一个因素。最近，铁也被证明影响分层少营养生态系统的生态和物种分布。这些铁有限区域的生产力(或缺乏生产力)对全球海洋碳预算具有重要意义。有了可靠的、可在船上部署的铁传感器，就可以在常规基础上获得高分辨率的数据集，从而更好地了解全球生物地球化学相互作用。这项建议旨在通过开发一种可用于极大地扩展建模人员可用的数据的现场工具，为提高测量覆盖率采取具体步骤。该项目将为研究生和本科生提供培训，并在斯克里普斯新开设的斯克里普斯制造空间开设本科生工程班。该项目将把硫化物Fe3+离子选择电极(Fe-ISE)集成到正在进行的和现场自主测量系统中。研究人员将通过以下方式校准和测试这些系统：1)将Fe-ISE测量的Fe3+离子活度与竞争配体交换-吸附阴极溶出伏安法(CLE-ACSV)独立测定的可溶性无机铁浓度进行比较，以及2)在人工海水介质中以众所周知的溶解有机配体背景作为模拟校准系统对Fe-ISE进行校准。这项提议的第二个目标是加强我们对硫化物ISE表面存在的复杂化学的理解，这些化学存在于一个不均匀的溶解有机物质池中，例如海水。预计该项目将产生一种改进的Fe-ISE方法，适合长期自主使用。预计该项目将描述/开发一套仪器，适用于长期监测码头位置的海洋变量、船上在航系统，以及潜在的自主系泊和剖面系统。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The lack of available iron (Fe) in seawater is widely accepted as a factor that limits phytoplankton growth in extensive high nutrient, low chlorophyll (HNLC) ocean areas, as well as some coastal upwelling regions. More recently, iron has been shown to impact the ecology and species distribution of stratified oligotrophic regimes as well. Productivity (or lack thereof) at the scale of these iron limited areas is significant to the global marine carbon budget. The availability of a reliable, ship-deployable Fe sensor would permit high resolution datasets to be obtained on a routine basis, resulting in improved understanding of global biogeochemical interactions. This proposal is designed to make concrete steps toward improving measurement coverage by developing a field instrument that could be used to greatly expand the data available to modelers. This project will provide training for graduate and undergraduate students and an undergraduate engineering class in the newly opened Scripps Makerspace at Scripps. This project will integrate the chalcogenide Fe3+ ion selective electrode (Fe-ISE) into underway and in situ autonomous measuring systems. The researchers will calibrate and test these systems through: 1) comparison of the Fe3+ ion activity measured by the Fe-ISE to the concentration of soluble inorganic iron determined independently by competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV), and 2) calibration of the Fe-ISE in an artificial seawater medium with a well-understood dissolved organic ligand background serving as a mimetic calibration system. A secondary objective of this proposal is to enhance our understanding of the complex chemistry that exists at the surface of the chalcogenide ISE in the presence of a heterogeneous dissolved organic matter pool, such as seawater. It is expected that this project will yield an improved Fe-ISE methodology that is suitable for long term autonomous use. It is also expected that this project will describe/develop an instrument package suitable for long term monitoring of oceanographic variables at pier locations, shipboard underway systems, and potentially autonomous moored and profiling systems.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.