Air-Sea CO2 and Dissolved Inorganic Carbon System for Autonomous Moored and Surface Vehicle Applications

Lead PI: Andrienne Sutton, NOAA Pacific Marine Environmental Laboratory
Start Year: 2018 | Duration: 3 years
Partners: University of Washington, Monterrey Bay Aquarium Research Institute, University of Hawaii

The ocean has absorbed about a quarter of anthropogenic carbon dioxide (C02) from the burning of fossil fuel and deforestation, resulting in a decrease of seawater pH and carbonate ion concentration. This phenomenon, referred to as “ocean acidification,” has the potential to directly impact marine life such as calcifying organisms that use dissolved calcium and carbonate ions to build external skeletons and shells. Shellfish, shallow-water tropical corals, and calcareous plankton are some examples of these economically and ecologically critical marine calcifiers. In order to quantify ocean acidification, two parameters of the inorganic carbon system must be measured in order to calculate the availability of calcium carbonate minerals (also known as saturation state) and determine the influence on calcification and dissolution. Aragonite saturation state is the ocean acidification metric with measurement quality goals set by the Global Ocean Acidification Observing Network (GOA-ON; www.goa-on.org), a collaborative international effort to document the status and progression of ocean acidification and understand its drivers and impacts. No autonomous sensor exists today with the measurement quality sufficient to detect long-term anthropogenically-driven changes in aragonite saturation state. This current lack of technology contributes significantly to the large observing gaps in GOA-ON and the global surface ocean CO2 observing network. Many of these observing gaps exist in regions of the globe that may be the most vulnerable to ocean acidification and to climate-linked political instability, such as coastal Africa, India, and southeast Asia.
The major outcome of this 3-year proposal is two prototype combined air-sea pCO2 and DIC systems with successful deployments on autonomous platforms in coastal waters. We expect a similar impact as a previous MBARl/PMEL development partnership, which resulted in transfer of a moored autonomous CO2 technology to a commercial manufacturer in 2009 and subsequent development of a network of >50 air-sea CO2 buoy time series observations and dozens of autonomous surface vehicle transects from the Arctic to the Southern Ocean. Expanding that network to climate quality pC02-DIC observations on buoys and autonomous surface vehicles will be transformative to global carbon cycle and ocean acidification research.