Calcification was assessed via the buoyant weighing technique using a balance precise to +-0.01 g, yielding a precision of calcification estimates of +-1% or better. Corals which died, experienced >25% partial mortality, or Porites which were attacked by the predatory nudibranch Phestilla spp. were dropped from the calcification analysis.

Tank treatments:

Below, "High" or "Low" pH refers to target pH levels. "Fed" or "Unfed" refers to whether the tank was fed zooplankton not.

Tank t1: High pH, Unfed
Tank t2: High pH, Fed
Tank t3: Low pH, Unfed
Tank t4: Low pH, Fed
Tank t5: High pH, Fed
Tank t6: Low pH, Unfed
Tank t7: Low pH, Fed
Tank t8: High pH, Unfed

Location information:

​The coral collection sites were the reef around HIMB and the reef adjacent to Kaiona Beach Park in Waimanalo (about 1 mile north of the Makai Pier). The lat/long for the approximate center of the sampling area at each site are as follows, and the sampling at each site was located within about +/- 200 m of that central point:

Kane'ohe Bay: 21.4336 N, -157.7861 W
Waimanalo Bay: 21.3272 N, -157.6811 W

The tank experiments were conducted at the Point Lab on Coconut Island, which is ~18 km from the sampling area in Waimanalo Bay and adjacent to the sampling area in Kane'ohe Bay. The high pH treatment was ambient Kane'ohe Bay seawater chemistry (pH ~7.9-8.0) whereas the target for the low pH treatment was ~0.25 units below ambient.