Development of Chemical Sensors and In-Situ Calibration: Enhanced Monitoring and Measurement of pH and Redox in Diffuse Flow Hydrothermal Systems

该项目要求支持pH和氧化还原传感器的开发、校准和测试，这些传感器最近已纳入自动校准系统。pH和氧化还原可以控制大洋中脊弥漫性热液栖息地等区域地球化学系统和生物系统之间的传质。要了解这些系统之间的联系，需要更长期的观察，这就需要对pH和氧化还原传感器进行原位校准。随着电缆观测站提供的深海喷口/附近电源的可用性，涉及现场测量和校准的仪器对于将定性观测转化为定量过程至关重要。pi提出了一项为期三年的研究，包括现场和实验室项目，目的是提高在低温到中等温度下复杂化学和生物系统中化学传感器的性能。研究的第一阶段包括对最近部署在漫流喷口的原位校准设备进行技术升级。所要求的资金将用于添加额外的pH缓冲流体储层，用于固态pH电极的三点pH校准。此外，安装pH和氧化还原传感器的单元将被重新设计，并做得更小，以减少内部体积，增加信号响应时间和灵敏度。第二阶段需要重新配置用于实时测量的独立校准单元，加强与HOV和ROV资产的配合使用。实验室研究计划包括陶瓷pH电化学传感器系统的测试和新型na基参考电极的开发，该电极可能特别适用于化学、物理和时间条件，与漫流热液喷口处的长期监测应用相一致。

This project requests support for development, calibration, and testing of pH and redox sensors that have recently been incorporated into an auto-calibration system. pH and redox can control mass transfer between geochemical and biological systems existing in areas such as diffuse flow hydrothermal habitats at mid-ocean ridges. To understand the linkages between these systems requires longer term observations, which create the requirement for in-situ calibration of pH and redox sensors. With the availability of power sources at/near deep-sea vents provided by cabled observatories, instrumentation involving in-situ measurement and calibration will be essential to transform qualitative observations to quantitative processes. The PIs propose a three year study involving both field and lab programs with the objective of improving the performance of chemical sensors in complex chemical and biological systems at low to moderate temperatures. Phase one of the study involves technical upgrades to the in-situ calibration device recently deployed at diffuse flows vent sites. Funds requested will be used to add additional pH buffer fluid reservoirs for three point pH calibration for the solid state pH electrode. Moreover, the unit that houses the pH and redox sensors will be redesigned and made smaller to decrease the internal volume and increase signal response time and sensitivity, respectively. Phase two entails reconfiguration of the stand alone calibration unit for real-time measurements, enhancing use with HOV and ROV assets. Laboratory studies are planned that involve testing of ceramic pH electrochemical sensor systems and development of a new Na-based reference electrode that may be particularly suitable for chemical, physical and temporal conditions consistent with long-term monitoring applications at diffuse flow hydrothermal vent sites.