Speaker: Adam Subhas ( California Institute of Technology)

Adam is speaking about "The Dissolution of Calcite in Seawater and its Potential as a Carbon Storage Technology" and says the following about his talk:
Near-equilibrium dissolution of calcite in seawater contributes significantly to the regulation of atmospheric CO2 on thousand-year timescales.  In this talk, I will show results from an isotope tracer-based approach to measure calcite dissolution rates across a range of saturation states.  SIMS analysis of the calcite surface also reveals a deep connecction between the solid and seawater.  The most surprising result from these experiments is that the enzyme carbonic anhydrase (CA) increases the dissolution rate by almost 2.5 orders of magnitude, an effect most pronounced close to equilibrium. CA can be a catalyst for carbonate dissolution through several different potential reaction mechanisms, not only equilibrating CO2 and H2CO3, but also through its catalytic protolysis of water.  I will also describe briefly results of a new flow-through reactor system aimed at engineering catalyzed carbonate dissolution to become an effective carbon storage technology.  This system can work in seawater and freshwater.