Deployable in Situ Electrochemical Analyzer (ISEA) for Remote and Automatic Analysis of O2, H2S and Sulfur Species in Hydrothermal Vent Environments

P.I.路德 0136671本项目拟购买一台现场电化学分析仪（ISEA），该分析仪可部署在任何海洋深度的着陆器、系泊设备和CTD型剖面仪上，用于沃茨和孔隙沃茨的远程水生实验。利用该仪器，在一次电位扫描过程中，可以在金汞齐固态电极上同时测定多种氧化还原物种。这些物质包括溶解氧、硫化物、硫代硫酸盐、多硫化物、碘化物、Fe（II）、Mn（II）和FeS。氧气可以高精度和高灵敏度测量，总溶解硫化物也可以测量。测量不需要化学操作，最多可在不同深度和位置安装四个工作电极，以获得水柱中的化学信息。该分析仪是监测重要氧化还原状况的理想选择，例如近岸和陆架环境中季节性缺氧的发展、热液喷口处硫化学的变化以及沉积物、停滞海湾、河口和盆地中氧化还原物种的分布。在以前提交的一份文件中，这些研究领域被定为进行衡量的目标，但审查人员表示，这过于雄心勃勃，只应选择一个领域进行进一步的工作。本提案的重点是热液喷口研究。喷口的一个主要问题是，喷口和扩散流化学的变化会影响生物体在不同地点定居的方式？最近的研究表明，不同的生物有机体存在于不同的化学生态位中。因此，能够测量各种氧化还原物种的原位传感器对于提高我们对这些环境中时间和空间尺度上的水化学的地球化学研究的理解是理想的。原位电化学分析仪原型已经成功地用于DSV Alvin，并且现在可以从Analytical Instrument Systems，Inc.该系统设计使用DSV Alvin的直流电源，由潜水器中的操作员控制潜艇的操纵器在给定的通风口位置部署电极。这项技术的下一步发展是为系统增加远程或自动功能，以监测各种系统中的时间变化。虽然ISEA是一个单一的系统，它将有四个Au/Hg工作电极，四个温度和pH传感器与每个工作电极集成。本质上，ISEA是一个分析仪中用于伏安法、温度和pH的四个独立的仪器包，允许分析四个独立的位置/深度。作为本提案的一部分，将对金汞合金（Au/Hg）电极进行长期部署测试。测试将包括在特拉华州大学港口的河口沃茨和热液喷口沃茨的长期部署。

P.I. Luther 0136671This project proposes to purchase an in situ electrochemical analyzer (ISEA) that can be deployed at any ocean depth on landers, moorings and CTD type profilers for remote aquatic experiments in waters and porewaters. With this instrument, many redox species can be determined simultaneously by voltammetry at a gold-amalgam solid-state electrode during one potential scan. These species include dissolved oxygen, sulfide, thiosulfate, polysulfides, iodide, Fe(II), Mn(II), and FeS. Oxygen can be measured with high precision and sensitivity as can total dissolved sulfide. No chemical manipulations are necessary for measurement and up to four working electrodes can be mounted at different depths and locations to obtain chemical information in the water column. This analyzer is ideal for monitoring important redox regimes such as the development of seasonal anoxia in nearshore and shelf environments, the changes in sulfur chemistry at hydrothermal vents and the profiles of redox species in sediments, stagnant bays, estuaries and basins. In a previous submission, these areas of study were targeted for making measurements but the reviewers indicated that this was too ambitious and only one should be selected for further work. In this proposal, the focus is on hydrothermal vent research. A major concern at vents is; what are the changes in vent and diffuse flow chemistry that affect the way organisms colonize different sites? Recent work has shown that different biological organisms reside in different chemical niches. Thus, in situ sensors that can measure a variety of redox species would be ideal for improving our understanding of biogeochemical studies of water chemistry on temporal and spatial scales in these environments.A prototype in situ electrochemical analyzer has been successfully used on the DSV Alvin and is now commercially available from Analytical Instrument Systems, Inc. This system was designed to use DC power from DSV Alvin with electrodes deployed at given vent locations by the submarine's manipulators controlled by an operator in the submersible. The next step in development of this technology is to add remote or automatic capability to the system to monitor temporal changes in a variety of systems. Although the ISEA is a single system, it will have four Au/Hg working electrodes with four temperature and pH sensors integrated with each of the working electrodes. In essence, the ISEA is four separate instrument packages for voltammetry, temperature and pH in one analyzer, which permits analysis of four separate locations/depths. As part of this proposal the gold-amalgam (Au/Hg) electrodes will be tested for long-term deployment. The testing will include long-term deployment in estuarine waters at the University of Delaware's harbor and at hydrothermal vent waters.