Dataset: Shaw 2016: Acropora pulchra calcification experiment 1

These data were obtained during an experiment performed in July 2015 at back reef (10m depth), Moorea, French Polynesia. To test intraspecific variation in the response of corals to ocean acidification and temperature, a common garden approach was used to cultivate clonal replicates of four colonies of Acropora pulchra. Calcification rates of A. pulchra were compared at two pCO2 levels (~400 uatm and ~1000 uatm) and two temperatures (~27 C and ~30 C). Colonies were incubated for 3 weeks in eight mesocosms (each 150 L in volume), with each of the four temperature–pCO2 combinations replicated in two randomly assigned tanks.

Buoyant weights of the corals were recorded at the beginning of the incubation and after 3 weeks in the treatments. The difference between the initial and final buoyant weight was converted to dry skeletal weight using the aragonite density of 2.93 g cm-3, in accordance with the mineral form of CaCO3 deposited by A. pulchra. Rates of net calcification (Gn) were normalized to the area of organisms estimated using wax dipping (Stimson and Kinzie 1991).

Sample collection and preparation:

One colony of A. pulchra was collected from each of four back reef locations (<1 m depth) in Moorea, French Polynesia and grown together in a common garden (~5 m depth) in the back reef on the north shore.  Each location was >1.25 km from any other sampling location, thereby increasing the likelihood that they represent unique host genotypes which are referred to as genotype A–D. The four colonies were grown in the common garden for 10–15 months to remove physiological effects attributed to variation in physical conditions at each collection location. Twenty-four branches (all of similar shape and length of ~5 cm) were harvested from each colony on the common garden on July 9, 2015, transported to the Richard B. Gump South Pacific Research Station, and prepared as nubbins (Birkeland 1976).  For full methodology see Shaw et al. 2016.