POSSIBILITY OF MEASURING CO₂ CONCENTRATION IN SEAWATER WITH ELECTRODES

Abstract

 In order to quantify the blue carbon effect, continuous measurement of CO₂ in the field is desired. Redox potential in seawater changes greatly due to the dissolution of CO₂, but it also changes significantly due to dissolved oxygen (DO) consumption. In this study, we investigated the redox reaction associated with the dissolution of CO₂ and the DO consumption due to oxidation of reducing substances. The mechanism of CO₂ dissolution was clarified by (1) dissolving CO₂ in seawater; (2) the relationship between precipitation and pH; (3) the dissolved CO₂ concentration; (4) comparing the experimental results with theoretical values. Furthermore, the redox reaction in a system in which CO₂ and DO compete was clarified through the redox potential. The findings of this study suggested the possibility of measuring dissolved CO₂ concentration by redox potential in the field.