Collaborative Research: Accelerated Development of New, Scalable pH Sensors for Global Ocean Observational Networks

通过生物地球化学Argo和全球海洋酸化观测网等协调努力，DuraFET pH传感器是全球观测网的关键组成部分。这些pH传感器已被部署在数百个自主剖面浮标、水下滑翔机和系泊上，以研究从潮间带、珊瑚礁到开阔海洋等环境中的海洋碳循环。此外，它们通常用于实验室中生态系统，以研究海洋酸化的影响。DuraFET的关键使能技术是由霍尼韦尔公司制造的离子敏感场效应晶体管（ISFET）半导体芯片。霍尼韦尔ISFET具有几个独特的特点，使其相对于竞争对手具有优越的性能。这在本质上导致了DuraFET pH传感器的唯一来源，并代表了海洋碳监测的关键漏洞。为了解决这个问题，该提案旨在加速可替代的pH传感器的开发，这些传感器可以按比例缩放以适应当前全球海洋观测网络的需求。具体来说，该项目将测试和开发两种有前景的pH传感器候选产品，它们能够在自主平台（如剖面浮标和滑翔机）上长期部署（数年）至2公里深度，以及用于系泊仪器和实验室中尺度应用。首先，将评估市售光学pH光电传感器（由PyroScience分发）的性能。这是一种相对较新的海洋传感器，因此它的性能还没有得到充分的表征，使化学海洋学家满意。其次，将开发一种利用来自不同供应商的ISFET的pH传感器。这两种pH传感器都是固态的，体积小，功耗低，使其成为自动驾驶平台的理想选择。传感器将在实验室中对pH响应、长期漂移、盐度、温度和压力影响、响应时间和滞后进行彻底的表征。这两种传感器随后将部署在海岸系泊、水下滑翔机和剖面浮标上，在数月至数年内评估各种条件下的原位性能。这一发展的成果将通过经常性的网络研讨会、出版物和与工业界的合作，迅速有效地与海洋学界分享。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The DuraFET pH sensor is a key component of global observation networks through coordinated efforts such as Biogeochemical Argo and the Global Ocean Acidification Observation Network. These pH sensors have been deployed on hundreds of autonomous profiling floats, underwater gliders, and moorings to study ocean carbon cycling in environments ranging from the intertidal zone, coral reefs, to the open ocean. Additionally, they are commonly utilized in laboratory mesocosms to study impacts of ocean acidification. The key enabling technology for the DuraFET is an Ion Sensitive Field Effect Transistor (ISFET) semiconductor chip, manufactured by Honeywell Co. The Honeywell ISFET has several unique features that give it superior performance relative to its competitors. This in essence results in a sole-source for DuraFET pH sensors, and represents a key vulnerability for ocean carbon monitoring. To address this, this proposal aims to accelerate the development of alternative pH sensors that can be scaled to fit the current needs of global ocean observational networks.Specifically, this project will test and develop two promising pH sensor candidates that are capable of long-term deployments (years) to 2 km depth on autonomous platforms such as profiling floats and gliders, as well as for moored instrumentation and laboratory mesocosm applications. First, the performance of a commercially available optical pH optode sensor (distributed by PyroScience) will be assessed. This is a relatively new sensor for oceanography, thus its performance has not been thoroughly characterized to the satisfaction of chemical oceanographers. Second, a pH sensor that utilizes an ISFET from a different supplier will be developed. Both pH sensors that will be explored are solid state, small, and low-power, making them good candidates for autonomous platforms. The sensors will be thoroughly characterized in the laboratory for pH response, long term drift, salinity, temperature, and pressure effects, response time, and hysteresis. Both sensors will then be deployed on coastal moorings, underwater gliders, and profiling floats to assess in situ performance across a range of conditions over months to years. Results from this development will be rapidly and efficiently shared with the oceanographic community through recurring webinars, publications, and collaboration with industry.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.