Role of carbonic anhydrase as an activator in carbonate rock dissolution and its implication for atmospheric CO_2 sink

摘要

The conversion of CO_2 into H~+ and is a relatively slow reaction. Hence, its kinetics may be rate determining in carbonate rock dissolution. Carbonic anhydrase(CA), which is widespread in nature, was used to catalyze the CO_2 conversion process in dissolution experiments of limestone and dolomite. It was found that the rate of dissolution increases by a factor of about 10 after the addition of CA at a high CO_2 partial pressure(Pco_2)for limestone and about 3 at low Pco_2 for dolomite. This shows that reappraisal is necessary for the importance of chemical weathering(including carbonate rock dissolution and silicate weathering)in the atmospheric CO_2 sink and the mysterious missing sink in carbon cycling.