Water parameters measured twice a week for 96 days in either sea water with the current pH or reduced pH (high-CO2).

Data presented as means (±S.E.M) with two replicates per treatment. During the acclimation period, the salinity was 32.0±0.14 ‰, measured directly and simultaneously from the incoming sea water in all treatments. in situindicates values at ambient temperature. STPindicates values measured at standard temperature (0°C) and pressure (1 atm). N5 indicates pCO2 values normalised to 5°C according to the isochemical temperature effect on seawater of 4.23%. STP*N5indicates pCO2N5measured at standard temperature (0°C) and pressure (1 atm). Table modified from Gräns et al. (2014).