Single Calcite Particle Dissolution Kinetics: Revealing the Influence of Mass Transport.

Calcite dissolution kinetics at the single particle scale are determined. It is demonstrated that at high undersaturation and in the absence of inhibitors the particulate mineral dissolution rate is controlled by a saturated calcite surface in local equilibrium with dissolved Ca 2+ and CO 3 2- coupled with rate determining diffusive transport of the ions away from the surface. Previous work is revisited and inconsistencies arising from the assumption of a surface-controlled reaction are highlighted. The data have implications for ocean modeling of climate change.