Seawater carbonate chemistry, calcification and dissolution response, and skeletal mineralogy of benthic orhanisms during experiments, 2011

• Main Author: Ries, Justin B
• Format: Dataset
• Language: English
• Published: PANGAEA 2011
• Subjects: Alkalinity; Gran titration (Gran; 1950); total; standard deviation; Animalia; Aragonite saturation state; Arbacia punctulata; Argopecten irradians; Arthropoda; Benthic animals; Benthos; Bicarbonate ion; Calcification/Dissolution; Calcification response; Calcite; magnesium/calcium ratio; Calcite/Aragonite; Calcite/Aragonite ratio; Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Callinectes sapidus; Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; partial pressure; Chlorophyta; Cnidaria; Coast and continental shelf; Containers and aquaria (20-1000 L or < 1 m**2); Coverage; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.770088; https://doi.org/10.1594/PANGAEA.770088

Increasing atmospheric pCO2 reduces the saturation state of seawater with respect to the aragonite, high-Mg calcite (Mg/Ca > 0.04), and low-Mg calcite (Mg/Ca < 0.04) minerals from which marine calcifiers build their shells and skeletons. Notably, these polymorphs of CaCO3 have different solubilities in seawater: aragonite is more soluble than pure calcite, and the solubility of calcite increases with its Mg-content. Although much recent progress has been made investigating the effects of CO2-induced ocean acidification on rates of biological calcification, considerable uncertainties remain regarding impacts on shell/skeletal polymorph mineralogy. To investigate this subject, eighteen species of marine calcifiers were reared for 60-days in seawater bubbled with air-CO2 mixtures of 409 ± 6, 606 ± 7, 903 ± 12, and 2856 ± 54 ppm pCO2, yielding aragonite saturation states of 2.5 ± 0.4, 2.0 ± 0.4, 1.5 ± 0.3, and 0.7 ± 0.2. Calcite/aragonite ratios within bimineralic calcifiers increased with increasing pCO2, but were invariant within monomineralic calcifiers. Calcite Mg/Ca ratios (Mg/CaC) also varied with atmospheric pCO2 for two of the five high-Mg-calcite-producing organisms, but not for the low-Mg-calcite-producing organisms. These results suggest that shell/skeletal mineralogy within some--but not all--marine calcifiers will change as atmospheric pCO2 continues rising as a result of fossil fuel combustion and deforestation. Paleoceanographic reconstructions of seawater Mg/Ca, temperature, and salinity from the Mg/CaC of well-preserved calcitic marine fossils may also be improved by accounting for the effects of paleo-atmospheric pCO2 on skeletal Mg-fractionation.