(L) Example of buoy that could carry the carbon dioxide sensor. (R) One module from the carbon dioxide sensor that Battelle will manufacture. Click to enlarge.

The need for ocean carbon measurements is becoming increasingly important because high levels of carbon dioxide in the oceans have led to ocean acidification in surface waters, which could have significant effects on a variety of marine organisms and ecosystems.

In 1992, MBARI scientists Gernot Friederich and Francisco Chavez realized the importance of collecting precise and frequent data regarding CO₂ exchange between the ocean and the atmosphere in order to better understand climate change. They designed the pCO₂ monitoring system using known gas-equilibration chemistry and state-of-the-art non-dispersive infrared (NDIR) spectroscopy. Measuring the partial pressure of CO₂ gives scientists an idea of whether the ocean is acting as a source or sink of CO₂ (relative to the atmosphere) at a given place and time. Such fluxes of CO₂ vary dramatically from place to place and over time.

In 2003, MBARI transferred the technology to NOAA, where scientists and engineers improved the design to make it more robust, more accurate, and easily manufactured. A reference calibration gas and two-way satellite data transmission capabilities were added to control the system remotely and receive data in near real-time.

The self-contained, modular design has the ability to be deployed on a wide variety of platforms. It is designed to operate unattended for more than 12 months at a time. Currently, more than a dozen systems are placed on a variety of buoys around the world. NOAA is using this system to develop a global array of moored observation systems to determine air-sea flux in support of the Global Ocean Observing System (GOOS).

The autonomous pCO₂ monitoring system will be manufactured at Battelle’s specialized scientific instrument manufacturing facility in Columbus and will be commercially available in summer 2009.