Table 1:

Seawater chemistry of experimental treatments

Treatment	Temperature (°C)	pH (total scale)	Alkalinity (μmol kg−1)	pCO2 (μatm)	Salinity
Incoming seawater	−1.0 ± 0.2	7.962 ± 0.005	2350.7 ± 3.5	484 ± 6	33.7 ± 0.3
Temperature −1°C
Ambient CO2	−0.6 ± 0.2	8.01 ± 0.01	2351.8 ± 1.9	425 ± 9	33.8 ± 0.3
Moderate CO2	−0.6 ± 0.2	7.84 ± 0.02	2350.6 ± 2.6	658 ± 28	33.7 ± 0.3
High CO2	−0.6 ± 0.1	7.66 ± 0.01	2350.9 ± 2.5	1008 ± 31	33.8 ± 0.4
Temperature +2°C
Ambient CO2	1.9 ± 0.2	7.99 ± 0.01	2351.9 ± 1.7	456 ± 11	33.7 ± 0.3
Moderate CO2	2.0 ± 0.2	7.84 ± 0.01	2350.9 ± 1.8	669 ± 18	33.7 ± 0.3
High CO2	2.0 ± 0.2	7.70 ± 0.01	2351.8 ± 2.2	935 ± 24	33.7 ± 0.3

Temperature, pH, alkalinity and salinity were measured in situ, and partial pressure of carbon dioxide (pCO₂) was calculated using seacarb (Lavigne and Gattuso, 2013) in R (R Development Core Team, 2013). All values are means ± SD.