Figure 2.

Calcification rates of Porites rus (left column) and Hydrolithon onkodes (right column) as a function of [CO₃²⁻] and [HCO₃⁻]. (a,b) Net calcification measured by buoyant weight over two, two-week incubations; (c,d) net calcification in the light measured by the alkalinity anomaly technique; and (e,f) calcification in the dark measured by the alkalinity anomaly technique. Each group of bars corresponds to three [CO₃²⁻] (approx. 100, 250 and 400 μmol kg⁻¹); colours of bars are dependent on [HCO₃⁻] (red approx. 1000, green approx. 1500, and blue approx. 2200 μmol kg⁻¹). All values are mean ± s.e.m. (n = 12 for buoyant weight and n = 4 for the light and dark calcification).