FY 1987

The effect of pressure on aragonite dissolution rates in seawater

Acker, J.G., R.H. Byrne, S. Ben-Yaakov, R.A. Feely, and P.R. Betzer

Geochim. Cosmochim. Acta, 51(8), 2171–2175, doi: 10.1016/0016-7037(87)90266-3 (1987)

Aragonite dissolution in seawater at variable pressure is well described by the equation Rate = ([CO] - [CO]) where [CO ] is the carbonate ion concentration at saturation, [CO ] is the observed carbonate ion concentration, and and n are empirical constants. Application of the equation Rate = (1-) to descriptions of aragonite dissolution rates (where = [CO<> ]/[CO ]) is appropriate at constant pressure, temperature and salinity. Our measurements in seawater at 5°C are consistent with the estimate -V = 36.5 cm/mole for the volume change accompanying aragonite dissolution. This result is somewhat higher than laboratory estimates, but lower than estimates based on calcite and difference between calcite and aragonite molar volumes.