Seawater carbonate chemistry, processes and elements during experiments with planktonic foraminifera Orbulina universa, 2004

• Main Authors: Russell, Ann D, Hönish, Bärbel, Spero, Howard J, Lea, David W
• Format: Dataset
• Language: English
• Published: PANGAEA 2004
• Subjects: Alkalinity; total; Aragonite saturation state; Bicarbonate ion; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (<20 L); Calcification/Dissolution; Calcite; dissolved; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chromista; Coulometric titration; EPOCA; EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; EXP; Experiment; Foraminifera; planktic; mass per shell; size average; wall thickness; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Heterotrophic prokaryotes; Laboratory experiment; Magnesium/Calcium ratio; Measured; Not applicable; OA-ICC; Ocean Acidification International Coordination Centre; Open ocean; Orbulina universa; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; Potentiometric open-cell titration; Ocean acidification; Planktonic foraminifera
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.721890; https://doi.org/10.1594/PANGAEA.721890

We investigate the sensitivity of U/Ca, Mg/Ca, and Sr/Ca to changes in seawater [CO3[2-]] and temperature in calcite produced by the two planktonic foraminifera species, Orbulina universa and Globigerina bulloides, in laboratory culture experiments. Our results demonstrate that at constant temperature, U/Ca in O. universa decreases by 25 +/- 7% per 100 µmol [CO3[2-]] kg**-1, as seawater [CO3[2-]] increases from 110 to 470 µmol kg**-1. Results from G. bulloides suggest a similar relationship, but U/Ca is consistently offset by ~+40% at the same environmental [CO3[2-]]. In O. universa, U/Ca is insensitive to temperature between 15°C and 25°C. Applying the O. universa relationship to three U/Ca records from a related species, Globigerinoides sacculifer, we estimate that Caribbean and tropical Atlantic [CO3[2-]] was 110 +/- 70 µmol kg**-1 and 80 +/- 40 µmol kg**-1 higher, respectively, during the last glacial period relative to the Holocene. This result is consistent with estimates of the glacial-interglacial change in surface water [CO3[2-]] based on both modeling and on boron isotope pH estimates. In settings where the addition of U by diagenetic processes is not a factor, down-core records of foraminiferal U/Ca have potential to provide information about changes in the ocean's carbonate concentration.