Development of an in situ total carbonate ion detector for marine use

Increasing atmospheric CO2 from anthropogenic sources is changing the chemistry of the oceans and altering the marine food web and the health of :isheries. NOAA’s National Ocean Service is responsible for maintaining the health of coastal regions to preserve :isheries. The ability to monitor the impact of increasing CO2 on marine organisms is crucial to this responsibility. NOAA’s call for autonomous direct measurement of carbonate ion in saline waters (SBIR topic # 8.2.5R) addresses the need to understand ocean chemistry, including changing pH and saturation states of calcite and aragonite (CaCO3) in response to increased atmospheric CO2 (pCO2). Ocean acidi:ication is changing entire ecosystems – affecting reproduction, growth, and respiration of a wide range of marine organisms. Sunburst Sensors, in collaboration with the University of South Florida (USF), proposes to determine the feasibility of developing an autonomous instrument to measure carbonate ion, based on combining the patented SAMI technology with a lead complexation-ultraviolet (UV) absorbance method for detection of carbonate anion. In Phase I, we will determine temperature dependence of the Pb2+ + CO32- reaction and molar absorbances, and investigate the feasibility of using UV LEDs or a deuterium light source and a UV spectrometer in an in situ sensor.