Omnibus Kruskal-Wallis one way analysis of variance results of mean (n = 2–4) ΔO2, ΔH+ and ΔCa2+ measured during three pCO2 treatment incubations (432, 1141, 2151 µatm) for different factors.

Significant effects at the Bonferroni corrected 0.83% levels are indicated in bold.

a

Δ denotes the difference in O2, H+ and Ca2+ respectively between the surface of shell and the bulk seawater determined by microsensor profiling (n = 2–4), averaged over each individual.

b

levels: photosymbiotic, heterotrophic.

c

levels: diatoms (Amphistegina radiata, Heterostegina depressa), dinoflagellates (Marginopora vertebralis), red algae (Peneroplis sp.), no symbionts (Quinqueloculina sp., Miliola sp.).

d

treatment groups represent each combination of species, pCO2, and light phase, according to box-plots represented in Figure 5, 6 and Figure S4.