FIGURE 1.

Experimental set up of the elevated CO₂ system (750 ppm CO₂). Dried ambient air from an external compressor is mixed with pure CO₂ in a mixing coil and flowing (1 L min^-1) into individual flumes and through a LI-COR 820 for continuous monitoring of concentration. The same set up was used for the ambient CO₂ treatment (∼380 ppm CO₂) for another three flumes, but without the addition of pure CO₂. A recirculating flow of seawater via the inflow- and outflow-pipe was restricted to 6 cm s^-1 and provided a unidirectional flow (indicated by a black-outlined arrow).