Seawater carbonate chemistry and calcification during experiments with a coral Madracis auretenra, 2010, supplement to: Jury, Christopher P; Whitehead, Robert F; Szmant, A M (2010): Effects of variations in carbonate chemistry on the calcification rates of Madracis auretenra (= Madracis mirabilis sensu Wells, 1973): bicarbonate concentrations best predict calcification rates. Global Change Biology, 16(5), 1632-1644

• Main Authors: Jury, Christopher P, Whitehead, Robert F, Szmant, A M
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2010
• Subjects: Animalia; Benthic animals; Benthos; Calcification/Dissolution; Cnidaria; Coast and continental shelf; Containers and aquaria 20-1000 L or < 1 m**2; Laboratory experiment; Madracis mirabilis; Not applicable; Single species; Tropical; Date; Identification; Experimental treatment; Carbonate system computation flag; Salinity; Temperature, water; Radiation, photosynthetically active; pH; Alkalinity, total; Carbon dioxide; Partial pressure of carbon dioxide water at sea surface temperature wet air; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Carbon, inorganic, dissolved; Aragonite saturation state; Calcite saturation state; Calcification rate of calcium carbonate; Calculated using seacarb after Nisumaa et al. 2010; m-cresol purple, Clayton & Byrne 1993; Alkalinity, measured accrding to Yao and Byrne 1998; Aluminium foil method Marsh, 1970; European network of excellence for Ocean Ecosystems Analysis EUR-OCEANS; European Project on Ocean Acidification EPOCA; Ocean Acidification International Coordination Centre OA-ICC; Clayton; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.729055; https://doi.pangaea.de/10.1594/PANGAEA.729055

Physiological data and models of coral calcification indicate that corals utilize a combination of seawater bicarbonate and (mainly) respiratory CO2 for calcification, not seawater carbonate. However, a number of investigators are attributing observed negative effects of experimental seawater acidification by CO2 or hydrochloric acid additions to a reduction in seawater carbonate ion concentration and thus aragonite saturation state. Thus, there is a discrepancy between the physiological and geochemical views of coral biomineralization. Furthermore, not all calcifying organisms respond negatively to decreased pH or saturation state. Together, these discrepancies suggest that other physiological mechanisms, such as a direct effect of reduced pH on calcium or bicarbonate ion transport and/or variable ability to regulate internal pH, are responsible for the variability in reported experimental effects of acidification on calcification. To distinguish the effects of pH, carbonate concentration and bicarbonate concentration on coral calcification, incubations were performed with the coral Madracis auretenra (= Madracis mirabilis sensu Wells, 1973) in modified seawater chemistries. Carbonate parameters were manipulated to isolate the effects of each parameter more effectively than in previous studies, with a total of six different chemistries. Among treatment differences were highly significant. The corals responded strongly to variation in bicarbonate concentration, but not consistently to carbonate concentration, aragonite saturation state or pH. Corals calcified at normal or elevated rates under low pH (7.6-7.8) when the seawater bicarbonate concentrations were above 1800 µm. Conversely, corals incubated at normal pH had low calcification rates if the bicarbonate concentration was lowered. These results demonstrate that coral responses to ocean acidification are more diverse than currently thought, and question the reliability of using carbonate concentration or aragonite saturation state as the sole predictor of the effects of ocean acidification on coral calcification. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne and Gattuso, 2011) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI).