Seawater carbonate chemistry, thickness and carbonate elemental composition of the test of juvenile sea urchins in a laboratory experiment

• Main Authors: Asnaghi, Valentina, Mangialajo, Luisa, Gattuso, Jean-Pierre, Francour, Patrice, Privitera, Davide, Chiantore, Mariachiara
• Format: Dataset
• Language: English
• Published: PANGAEA 2014
• Subjects: Alkalinity; total; standard deviation; Animalia; Aragonite saturation state; Benthic animals; Benthos; Bicarbonate ion; Calcite saturation state; Calculated using seacarb; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Containers and aquaria (20-1000 L or < 1 m**2); Corallina elongata; Cystoseira amentacea; Diameter; Dictyota dichotoma; Echinodermata; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Growth rate; Laboratory experiment; Location; Magnesium/Calcium ratio; Mediterranean Sea; Mediterranean Sea Acidification in a Changing Climate; MedSeA; OA-ICC; Ocean Acidification International Coordination Centre; Other; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.833328; https://doi.org/10.1594/PANGAEA.833328

Continuous anthropogenic CO2 emissions to the atmosphere and uptake by the oceans will cause a reduction of seawater pH and saturation state (Omega) of CaCO3 minerals from which marine calcifiers build their shells and skeletons. Sea urchins use the most soluble form of calcium carbonate, high-magnesium calcite, to build their skeleton, spines and grazing apparatus. In order to highlight the effects of increased pCO2 on the test thickness and carbonate elemental composition of juvenile sea urchins and potential differences in their responses linked to the diet, we performed a laboratory experiment on juvenile Paracentrotus lividus, grazing on calcifying (Corallina elongata) and non-calcifying (Cystoseira amentacea, Dictyota dichotoma) macroalgae, under different pH (corresponding to pCO2 values of 390, 550, 750 and 1000 µatm). Results highlighted the importance of the diet in determining sea urchin size irrespectively of the pCO2 level, and the relevance of macroalgal diet in modulating urchin Mg/Ca ratio. The present study provides relevant clues both in terms of the mechanism of mineral incorporation and in terms of bottom-up processes (algal diet) affecting top-down ones (fish predation) in rocky subtidal communities