Table 4 Measurements of pHcf from microelectrode in the light (pHcf_light) and dark (pHcf_dark), pHcf_δ11B calculated from skeletal δ11B, and estimated light:dark calcification ratios.

pHcf_light (±SE)pHcf_dark (±SE)ΔpHlight-dark (±SE)pHcf_δ11B (±SE)Light:dark calcification
(total scale)(total scale)(total scale)(total scale)
P. damicornis
pCO2 466 ppm, 28°C8.93 ± 0.308.03 ± 0.340.9 ± 0.58.20 ± 0.0719:81
pCO2 925 ppm, 28°C8.43 ± 0.227.92 ± 0.220.5 ± 0.38.10 ± 0.0835:65
pCO2 2807 ppm, 28°C8.24 ± 0.227.39 ± 0.170.9 ± 0.38.23 ± 0.0299:01
S. pistillata
pCO2 466 ppm, 28°C8.86 ± 0.077.80 ± 0.301.1 ± 0.68.29 ± 0.1250:50
pCO2 925 ppm, 28°C8.53 ± 0.157.86 ± 0.280.6 ± 0.38.28 ± 0.0263:37
pCO2 2807 ppm, 28°C8.20 ± 0.237.65 ± 0.140.6 ± 0.38.20 ± 0.01100:00*
pCO2 499 ppm, 31°C8.71 ± 0.127.96 ± 0.240.9 ± 0.38.16 ± 0.0527:73
pCO2 885 ppm, 31°C8.03 ± 0.146.95 ± 0.230.9 ± 0.38.04 ± 0.1099:01
pCO2 3194 ppm, 31°C8.01 ± 0.097.06 ± 0.080.9 ± 0.18.14 ± 0.11100:00*

pHcf_light, pHcf measured from microelectrode when the coral was in the light; uncertainty is reported as 1 SE of the replicates.

pHcf_dark, pHcf measured from microelectrode when the coral was in the dark; uncertainty is reported as 1 SE of the replicates.

ΔpHlight-dark, difference in light and dark pHcf microelectrode measurements pHcf_diurnal: pHcf calculated from δ11B; uncertainty is reported as 1 SE of the replicates.

Light:dark calcification, light:dark calcification ratios obtained from the weighting of pHcf_light and pHcf_dark measurements required to generate the δ11B-based estimates of pHcf (pHcf_δ11B) calculated from average of measured specimens within a treatment.

*When pHcf_diurnal average was > or = pHcf_light but still within errors of each other, we attributed a light:dark calcification of 100:00.