Dataset: Evensen and Edmunds 2016: seawater chemistry

These data are from an experiment performed in Moorea in May-June 2014. Aggregates of 12 colonies were placed in one of six tanks (1 aggregate per tank) at either ambient (~400 µatm) or high (~1100 µatm) pCO2 (3 tanks per treatment) for 28 days. Buoyant weights of the corals were recorded before and after incubation. See dataset "pCO2 flume May to Jun 2014 coral growth" https://www.bco-dmo.org/dataset/683932 for coral growth data during this experiment). 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 Pocillopora and Acropora. Rates of net calcification (Gn) were normalized to the tissue area, which was estimated using wax dipping (Stimson and Kinzie 1991).

In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne and Gattuso, 2013) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). pH was measured daily with the Orion 3-star pH sensor (with DG115-SC probe, Mettler Toldeo). Total alkalinity of seawater was measured from 50 mL samples taken every two days by open-cell potentiometric titrations using an automated titrator (T50 Mettler-Toledo). Aragonite and pCO2 parameters were calculated from measurements of total alkalinity, salinity, and pH (Gattuso et al. 2015).