CO₂ and the lowering of ocean pH, development and testing of a precise pH sensor for monitoring and impact assessment

Increasing output of CO₂ contributes to a lower pH in the oceans, see Keeling Curve at http://scrippsco2.ucsd.edu/home/. Undetected leaks from subsea CO₂ deposits may add to the trend and contribute to potential exposure stress (effects) of marine organism s. StatoilHydro apply for funding to support a 1 year pilot project on developing fine calibration methods (to ~0.02 of a pH unit) and conduct testing of a pH electrode which may be used for detecting, monitoring and impact assessment of increased amounts of CO₂ in seawater. We will obtain initial user experience at laboratory flow through, low temperature and high pressure conditions with an industrial pressure tolerant pH electrode.

Subsequently asses its applicability for use offshore by comparing precision of pH measurements to model desciptions of plumes of CO₂ leaks from sub-sea deposits, and use it to support measurements of pH stress (effects) on corals exposed to CO₂. Provided promising results, networking will be conducted in order to promote further sensor development and to establish a foundation for a more comprehensive future project. The proposed work builds on and supports a StatoilHydro Vista post doc study (Järnegren 2007), which includes NINA and NTNU, and addresses CO₂ mediated low pH stress on the deep living cold water coral Lophelia pertusa. Andrew Dickson of the Scripps Institution of Oceanography, USA will head calibration work and contribute on sensor development.

The coral and pH sensor studies uses/will use the unique test system for chemical, ecological and ecotoxicological studies built at IRIS (Skadsheim et al. 2007). Synergism will be obtained from the strategic institute program on biosensors at IRIS (Børseth 2006) and from field experience obtained by offshore deployment of the Biota Guard sensor concept initially developed at IRIS (http://www.biotaguard.no/).