Euechinoidea and Cidaroidea respond differently to ocean acidification

• Main Authors: Collard, Marie, Dery, Aurélie, Dehairs, Frank, Dubois, Philippe
• Format: Dataset
• Language: English
• Published: PANGAEA 2014
• Subjects: Acid-base regulation; Alkalinity; total; Animalia; Aquarium number; Aragonite saturation state; Behaviour; Benthic animals; Benthos; Bicarbonate ion; Calcite saturation state; Calculated; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Coelomic fluid; pH; Comment; Containers and aquaria (20-1000 L or < 1 m**2); Difference; Echinodermata; Eucidaris tribuloides; Feeding rate per individual; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Identification; Isotope ratio mass spectrometry; Laboratory experiment; North Atlantic; OA-ICC; Ocean Acidification International Coordination Centre; Paracentrotus lividus; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Potentiometric; Potentiometric titration; Salinity; Single species; Species; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.835967; https://doi.org/10.1594/PANGAEA.835967

The impact of the chemical changes in the ocean waters due to the increasing atmospheric CO2 depends on the ability of an organism to control extracellular pH. Among sea urchins, this seems specific to the Euechinoidea, sea urchins except Cidaroidea. However, Cidaroidea survived two ocean acidification periods: the Permian-Trias and the Cretaceous-Tertiary crises. We investigated the response of these two sea urchin groups to reduced seawater pH with the tropical cidaroid Eucidaris tribuloides, the sympatric euechinoid Tripneustes ventricosus and the temperate euechinoid Paracentrotus lividus. Both euechinoid showed a compensation of the coelomic fluid pH due to increased buffer capacity. This was linked to an increased concentration of DIC in the coelomic fluid and thus of bicarbonate ions (most probably originating from the surrounding seawater as isotopic signature of the carbon -delta 13C- was similar). On the other hand, the cidaroid showed no changes within the coelomic fluid. Moreover, the delta 13C of the coelomic fluid did not match that of the seawater and was not significantly different between the urchins from the different treatments. Feeding rate was not affected in any species. While euechinoids are able to regulate their extracellular acid-base balance, many questions are still unanswered on the costs of this capacity. On the contrary, cidaroids do not seem affected by a reduced seawater pH. Further investigations need to be undertaken to cover more species and physiological and metabolic parameters in order to determine if energy trade-offs occur and how this mechanism of compensation is distributed among sea urchins.