gcb2716-sup-0001-Table1.docWord document50KTable S1. Seawater carbonate chemistry measurements for each study station off the island of Vulcano (V) and in Papua New Guinea; Upa-Upasina (U) and Esa'Ala (E), R= reference station, S = elevated CO2 station. In Vulcano, temperature (range 18.6–27.7 °C), pH and salinity (= 38) were measured in Sept-Oct 2009, April 2010, July 2010, Sept-Oct 2010, May 2011, Sept–Oct 2011. In Papua New Guinea, temperature (range 28.2–31.4 °C), pH and salinity (= 34) were measured in April 2011. The pH and total alkalinity (Vulcano: mean TA, = 3; PNG: median TA values taken from Fabricius et al., 2011) were used to calculate the remaining parameters using CO2 SYS programme (using the constants of Roy et al., 1993 and Dickson, 1990 for KSO4).
gcb2716-sup-0002-Table2.docWord document34KTable S2. Mean (± SE) abundance, length and width of aragonite crystals deposited by Padina pavonica along the Vulcano CO2 gradient. Data derived from SEM analysis of fronds (n = 3 fronds per station), over calcified apical regions only (see frond images in Fig. 4), therefore do not reflect total means for whole fronds.

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