Development and Deployment of Autonomous and Remotely Operated Chemical Sensor System: Integrated Laboratory and Field Studies of Seafloor Hydrothermal Vent Fluids

该项目涉及化学传感器系统的持续开发、集成和应用，该系统可用于自主监测大洋中脊热液喷口流体中的关键成分。在地球科学中，热液喷口流体在帮助维持海洋化学方面发挥着关键作用，同时也为与深海喷口有关的壮观生物群落的起源和进化提供了必要的化学物质——无论是现在还是古代地质历史。在这里，研究人员确定了一个技术修改、实验室和喷口相关研究的综合计划，这将提高化学传感器数据在解释深海热液喷口系统方面的有效性。这项调查将有助于加强研究基础设施，这些基础设施将提供给参与广泛学科领域的研究和培训的海洋科学家和工程师。与密歇根大学和中国浙江大学的工程同事合作，扩大了对海洋科学研究的参与，并使研究人员能够应用纳米技术、微机械加工和过程控制软件和硬件方面的最新进展，以开发下一代自主化学传感器系统所需的概念。开发具有自主操作能力的化学传感器也很重要，因为光纤电缆海洋观测站正在取得进展，它将为海底和最终深海喷口的仪器提供电力，促进长期测量和无人值守的操作。此外，这项研究将受益于本科生参与美国国家科学基金会本科生研究经验（REU）计划-地球中的流体。明尼苏达大学的研究生也将参与这项研究。事实上，本科生和研究生与研究人员一起研究传感器的应用，并参加了海洋学研究巡航，同时在他们帮助创建的化学传感器和排气流体采样系统的海底部署中发挥了关键作用。氧化还原和pH值是所有地球化学和生物系统的主变量。因此，本研究的重点是在更长的时间和更大的温度范围内增强这些参数的测量。因此，目标如下：(1)扩展自主原位校准模块，以包括氧化还原成分（例如溶解的H2S）；(2)用纳米陶瓷组成的功能类似的装置取代传统的陶瓷pH测量传感器，潜在地增强在较低温度下的测量，减少校准的需要。纳米技术和微电子技术的最新进展使这成为可能；(3)将电化学传感器系统与新开发的热液采样器耦合，实现传感器触发的热液自动采集。通过将传感器系统与流体采样系统耦合，研究人员将获得一种集事件检测与事件响应于一体的仪器；(4)进行精细自动化协议的网络（internet， LAN）测试；(5)将实验室和现场校准和验证测量与东太平洋海底热液喷口部署相结合。研究人员在这个喷口系统有相当丰富的经验，所获得的数据将有助于实现技术和科学目标；(6)使用新设计的装有陶瓷pH传感器的流动反应器进行高温实验室实验。这些研究允许测试基于早期海底pH值（原位）测量数据的近临界条件下pH值升高的最新预测。

This project involves the continued development, integration, and application of chemical sensor systems that can be used autonomously to monitor key components in hydrothermal vent fluids at mid-ocean ridges. Hydrothermal vent fluids play a key role in the Earth sciences in helping to maintain ocean chemistry, while also providing chemicals essential for the origin and evolution of the spectacular communities of organisms associated with deep sea vents- now and in the ancient geological past. Here the investigators identify an integrated program of technical modifications and laboratory and vent related studies that will enhance the effectiveness of chemical sensor data for interpretation of deep-sea hydrothermal vent systems. The investigation will contribute to the enhancement of research infrastructure that will be available to ocean scientists and engineers involved in research and training in a wide range of disciplinary areas. Collaboration with colleagues in engineering at the University of Michigan and Zhejiang University in China has broadened participation in ocean science research and has allowed the investigators to apply recent advances in nanotechnology, micromachining, and process control software and hardware in developing concepts needed for the next generation of autonomous chemical sensor systems. Development of chemical sensors with autonomous operation capabilities is also important as progress is being made with fiber-optic cabled ocean observatories, which will provide power for instruments on the seafloor and ultimately at deep-sea vents, facilitating longer term measurements and unattended operation. Moreover, the research will benefit from the participation of undergraduate students in connection with the NSF Research Experiences for Undergraduates (REU) program - Fluids in the Earth. Graduate students at the University of Minnesota will also participate in the research. Indeed undergraduate and graduate students have worked with the investigators on sensor applications and participated in oceanographic research cruises, while playing a key role in the deployment on the seafloor of chemical sensors and vent fluid sampling systems that they helped to create.Redox and pH represent master variables in all geochemical and biological systems. Thus, this research focuses on enhancing the measurement of these parameters for longer times and over a greater range of temperatures. Accordingly, the objectives are as follows: (1) Extend the autonomous in-situ calibration module to include redox components (e.g., dissolved H2S); (2) Replace conventional ceramic sensor for pH measurement with a functionally similar device composed of nano-ceramic, potentially enhancing measurements at lower temperatures with less frequent need for calibration. Recent advances in nanotechnology and microelectronics now make this possible; (3) Couple electrochemical sensor systems with newly developed hydrothermal fluid samplers for sensor triggered autonomous acquisition of hydrothermal fluid. By coupling the sensor system with a fluid sampling system, the investigators will achieve an instrument that combines event detection with event response; (4) Perform network (internet, LAN) tests of refined automation protocols; (5) Integrate lab and field calibration and verification measurements with deployments at seafloor hydrothermal vents in the Eastern Pacific ocean. The researchers have considerable experience at this vent system, and the data obtained will contribute to both technical and scientific objectives; and, (6) Conduct high-temperature lab experiments using a newly designed flow reactor adapted with ceramic-based pH sensors. These studies permit testing of recent predictions of elevated pH values at near critical conditions based on earlier pH (in-situ) data measured at the seafloor.