Coral pH regulation of the calcifying fluid is modulated by seawater dissolved inorganic carbon concentration

• Main Authors: Comeau, Steeve, Tambutté, Eric, Carpenter, Robert C, Edmunds, Peter J, Evensen, Nicolas R, Allemand, Denis, Ferrier-Pagès, Christine, Tambutté, Sylvie, Venn, Alexander A
• Format: Dataset
• Language: English
• Published: PANGAEA 2017
• Subjects: Acid-base regulation; Alkalinity; total; standard error; Animalia; Aragonite saturation state; Benthic animals; Benthos; Bicarbonate ion; Calcification/Dissolution; Calcification rate; Calcification rate of calcium carbonate; Calcifying fluid; pH; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cnidaria; Containers and aquaria (20-1000 L or < 1 m**2); Figure; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gross photosynthesis rate; oxygen; Laboratory experiment; Laboratory strains; Net photosynthesis rate; Not applicable; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Photosynthesis rate of oxygen; per symbiont cell; Primary production/Photosynthesis; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.868353; https://doi.org/10.1594/PANGAEA.868353

Reef coral calcification depends on regulation of pH in the internal calcifying fluid in which the coral skeleton forms. However, little is known about calcifying fluid pH (pHCF) regulation, despite its importance in determining the response of corals to ocean acidification. Here, we investigate the impact of seawater dissolved inorganic carbon (DIC) concentration on calcifying fluid pH in the coral Stylophora pistillata in seawater with manipulated [DIC] and constant pH. Our results reveal that regulation of pHCF and calcification rates are sensitive to changes in seawater [DIC] in the light and dark. While part of this relationship can be explained by changes in rates of photosynthesis and respiration, our data point to the importance of seawater DIC in pH regulation of the coral's calcifying cells. Our findings contribute towards a mechanistic understanding of how and why coral calcification is sensitive to changes in seawater carbonate chemistry, which is needed for predicting effects of environmental change on coral reefs and for robust interpretations of isotopic paleoenvironmental records in coral skeletons.