Figure 2. Temporal pH and H⁺ development of diffusive boundary layer (DBL) of Marginopora vertebralis, measured consecutively at a single position on the calcite shell at a pCO₂ of 432 µatm, 30 µmol photons m⁻² s⁻¹ under zero flow conditions after flow (0.5 cm s⁻¹) was cut off at time = 0.