Publication Date:
2024-03-15
Description:
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.
Keywords:
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, dissolved; 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; Foraminifera, planktic, mass per shell; Foraminifera, planktic, size average; Foraminifera, planktic, 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; Radiation, photosynthetically active; Russell_etal_04; Salinity; Sample ID; Single species; Species; Strontium/Calcium ratio; Temperate; Temperature, water; Uranium/Calcium ratio
Type:
Dataset
Format:
text/tab-separated-values, 1631 data points
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