Parameters of the seawater carbonate system of the cultures.

Dissolved inorganic carbon and pH were measured upon terminal sampling of turbidostat cultures grown under ambient- (390 ppm) and elevated- (750 ppm) CO2 treatments. Total alkalinity, pCO2, carbonate (CO32−), bicarbonate (HCO3−) and free CO2 were calculated on the base of the temperature (18°C), salinity (35 g L−1), pH and concentrations of dissolved inorganic carbon, phosphate (21 µmol L−1) and silica (52.5 µmol L−1) using the software CO2SYS. n = 3, mean ±S.D.; n = 2 in treatments of 390, 750 pCO2 ppmv at the growth light of 31 µmol photons·m−2·s−1; for these estimates we present mean ±1/2 range.