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

 Funding Agency: NSF

 Project Lead: Grace Saba, Travis Miles

 Partners: Teledyne Webb, Waterlab

 Period of Performance: 10/1/2016 – 9/30/2021

 Total Budget: $882,647.00

 Project Summary:

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 (Ω) 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   pCO2 sensors, 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 PIs propose to: 1) 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; 2) test the new sensor suite via three glider deployments to provide a rigorous “groundtruthing”; 3) deliver the OA data in real-time; and 4) examine pH/Ω dynamics on the commercially important U.S. Northeast Shelf. The proposed testing in 2018 will benefit with rigorous groundtruthing via coordination of the high resolution glider mapping of pH and Ω side-by-side with Cai’s 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, DIC; total alkalinity, TA; and oxygen, O2) will be measured either underway or on board ship.

Intellectual Merit: The proposal will develop the integrated glider platform and sensor system for sampling pH and possibly Ω in the water column of the coastal ocean on a regional scale. The integration of simultaneous measurements from multiple sensors on one glider will allow one to distinguish interactions between the physics (temperature), chemistry (dissolved O2, salinity-based TA, and temperature-, salinity-, and O2-based DIC, Ω), and biology (fluorescence, backscatter) of the ecosystem. High spatial and temporal resolution in situ pH measurements and Ω estimations will be provided in habitats of commercially important fisheries in the U.S. Northeast Shelf where ocean pH/Ω information is most critically needed. Being able to monitor pH throughout the water column is critical in order to track the movement of low pH/Ω water, understand the variability of pH/Ω, and predict how mixing events and circulation will impact pH/Ω across the shelf. This capability will allow the PIs and others to identify habitats that are susceptible to periods of low pH/Ω and/or high temporal pH/Ω variability.

Broader Impacts: 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 including academic and government scientists, monitoring programs including those conducted by OOI, IOOS, NOAA and EPA, water quality managers, and commercial fishing companies. The data produced from this new technology will allow the community to identify high-risk regions and populations of commercially important species that are more prone to periods of reduced pH/Ω and ultimately will enable us to better manage essential habitats in the future, more acidic oceans. The open accessible, automated real-time data 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) would provide a warning system that would assist scientists studying ecological processes, water quality managers and conservationists to monitor impacts, and commercial operators to implement adaptive strategies. Finally, data resulting from this newly developed technology and future applications can help build and improve ecosystem models, specifically the development of coastal forecast models with the capability to predict the variability and trajectory of the low pH water. This project will also provide support for two early career researchers,