Measurements of microbial processes, dissolution, water and porewater chemistry during experiments on two coral reef sediments

Porewater pH profiles were measured in different regions of the chambers. Fluxes of oxygen, total alkalinity (as a measure of CaCO3 dissolution), dissolved organic carbon and nutrients were measured using incubations. Pigment concentrations were measured at the end of the experiment as a measure for microphytobenthos abundance and to calibrate the hyperspectral imaging results.

In both experiments, elevated pCO2 did not affect biotic processes. Elevated pCO2 caused an increase in dissolution of the Davies Reef sediments. The porewater pH measurements indicated that this is likely caused by the dissolution of high-magnesium calcites.