Collaborative Research: Developing a profiling glider pH sensor for high resolution coastal ocean acidification monitoring

海洋酸化具有重大的科学和社会影响，包括海洋生物地球化学的改变、生态系统改变带来的生态后果，以及因重要商业生物生存能力下降而造成的经济损失。然而，很少有时间序列和高分辨率的时空测量来跟踪低pH和低碳酸盐饱和度（Ù）水的存在和运动，特别是在有鳍鱼、龙虾和野生贝类的沿海地区。过去的海洋酸化监测工作（带有pH值的表面浮标或测量二氧化碳分压（pCO2）的传感器，科考船使用的pCO2流量系统，大型野外活动期间的水柱采样）要么空间分辨率低（系泊），要么成本高，时间和空间分辨率低（科考巡航）。因此，迫切需要部署新的、具有成本效益的技术，以便在我们的沿海海洋区域尺度上常规提供高分辨率水柱OA数据。自主水下剖面滑翔机已被证明是一项强大的技术，可以满足这一角色。各种各样的传感器已经成功地安装在Slocum滑翔机上；然而，安装在这些滑翔机上的pH传感器并没有收集到海洋pH值的直接测量数据。研究人员将开发集成的滑翔机平台和传感器系统，用于采样pH值，并可能在区域范围内采样沿海海洋水柱中的Ù。该项目将产生一种新的商用滑翔机pH传感器套件，它将为能够为广泛用户服务的实时国家沿海OA监测网络提供基础。此外，在一个滑翔机上集成多个传感器的同时测量将使人们能够区分生态系统的物理、化学和生物学之间的相互作用。研究人员将修改并集成基于离子敏感场效应晶体管（ISFET）的深度额定pH传感器，即深海DuraFET pH传感器系统，到Slocum滑翔机中。他们将通过在美国东北大陆架部署的三个滑翔机测试新的传感器套件，实时提供OA数据，并检查商业重要渔业栖息地的pH/Ù动态。通过协调高分辨率滑翔机绘制pH值和Ù，该项目将受益于严格的地面真相，并与NOAA OAP（海洋酸化计划）计划的ECOA（东海岸海洋酸化）巡航II相结合，其中全套碳酸盐参数（二氧化碳分压、pH值、溶解无机碳、总碱度和氧气）将在海上或船上测量。将在美国东北大陆架重要商业渔业栖息地提供高时空分辨率的原位pH测量和Ù估计。这种开放可访问的自动化实时数据将通过RUCOOL（罗格斯大学海洋观测领导中心）、MARACOOS（中大西洋地区协会沿海海洋观测系统）和THREDDS（专题实时环境数据分发系统）提供。这项新技术产生的数据将使研究人员和社区能够跟踪低pH/Ù水的运动，了解pH/Ù的可变性，预测混合事件和环流将如何影响整个大陆架的pH/Ù，确定高风险区域和更容易受到pH/Ù降低时期影响的商业重要物种种群，并最终将使未来更明智地管理必要的栖息地，更酸性的海洋。

Ocean acidification (OA) has significant scientific and societal ramifications including the alteration of ocean biogeochemistry, ecological consequences associated with altered ecosystems, and economic losses due to the decreased survival of commercially important organisms. Yet few time series and high resolution spatial and temporal measurements exist to track the existence and movement of low pH and low carbonate saturation (Ù) water, specifically in coastal regions where finfish, lobster, and wild stocks of shellfish are located. Past ocean acidification monitoring efforts (surface buoys with pH or sensors that measure partial pressure of carbon dioxide, or pCO2, flow-through pCO2 systems utilized by research vessels, water column sampling during large field campaigns) have either low spatial resolution (mooring) or high cost and low temporal and spatial resolution (research cruises). Therefore, there is a critical need to deploy new, cost-effective technologies that can routinely provide high resolution water column OA data on regional scales in our coastal ocean. Autonomous underwater profiling gliders have proven to be a robust technology that fulfills this role. A variety of sensors have successfully been mounted on Slocum gliders; however, no direct measurements of ocean pH have been collected by pH sensors mounted on these gliders. The researchers will develop the integrated glider platform and sensor system for sampling pH and possibly Ù in the water column of the coastal ocean on a regional scale. This project will result in a new commercially available glider pH sensor suite that will provide the foundation of what could become a real-time national coastal OA monitoring network with the capability of serving a wide range of users. Additionally, the integration of simultaneous measurements from multiple sensors on one glider will allow one to distinguish interactions between the physics, chemistry, and biology of the ecosystem. The researchers will modify and integrate a deep rated version of the Ion Sensitive Field Effect Transistor (ISFET)-based pH sensor, the Deep-Sea DuraFET pH sensor system, into a Slocum glider. They will test the new sensor suite via three glider deployments on the U.S. Northeast Shelf, deliver the OA data in real-time, and examine pH/Ù dynamics in habitats of commercially important fisheries. The project will benefit with rigorous groundtruthing via coordination of the high resolution glider mapping of pH and Ù side-by-side NOAA OAP's (Ocean Acidification Program) planned ECOA (East Coast Ocean Acidification) cruise II where a full suite of carbonate parameters (pCO2, pH, dissolved inorganic carbon, total alkalinity, and oxygen) will be measured either underway or on board ship. High spatial and temporal resolution in situ pH measurements and Ù estimations will be provided in habitats of commercially important fisheries in the U.S. Northeast Shelf. This open accessible, automated real-time data will be made available through RUCOOL (Rutgers University Center for Ocean Observing Leadership), MARACOOS (Mid-Atlantic Regional Association Coastal Ocean Observing System), and THREDDS (Thematic Real-time Environmental Data Distribution System). The data produced from this new technology will allow the researchers and the community to track the movement of low pH/Ù water, understand the variability of pH/Ù, predict how mixing events and circulation will impact pH/Ù across the shelf, identify high-risk regions and populations of commercially important species that are more prone to periods of reduced pH/Ù, and ultimately will enable more informed management of essential habitats in the future, more acidic oceans.