Gas concentrations in both treatments remained stable for the
duration of the experiment, and resulted in pH (total scale) of 7.86
(control) and 7.31 (treatment), and corresponding VArag values of
1.71 and 0.53 respectively (Table 1). Thus, the control pCO2
condition was supersaturated with respect to aragonite while the
elevated pCO2 condition was under-saturated. The pH and
saturation state of the control are lower than what would be
expected from equilibration with air, which may reflect variation
in near-shore conditions during the course of the experiment and/
or incomplete equilibration of the incoming flow-through water
with the control bubbled air. As such, calculated pCO2 levels (from
CO2sys) were 626 matm for the control and 2440 matm for the
treatment (averaged across trials). There were clear differences in
pH between control- and treatment-pCO2-equilibrated aquaria.Temperature, salinity and alkalinity remained steady for the duration of the experiment (Table 1).