Seawater carbonate chemistry and Emiliania huxleyi mass and size, 2011

• Main Authors: Beaufort, Luc, Probert, Ian, de Garidel-Thoron, Thibault, Bendif, E M, Ruiz-Pino, Diana, Metzi, N, Goyet, Catherine, Buchet, Noëlle, Coupel, Pierre, Grelaud, Michaël, Rost, Björn, Rickaby, Rosalind E M, De Vargas, Colomban
• Format: Dataset
• Language: English
• Published: PANGAEA 2011
• Subjects: Age; dated; Alkalinity; total; Antarctic; Aragonite saturation state; Bicarbonate ion; Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; CTD; Sea-Bird SBE 911plus; Emiliania huxleyi; diameter; weight; standard error; EPOCA; Estimated by measuring brightness in cross-polarized light (birefringence); EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Indian Ocean; LATITUDE; LONGITUDE; Measured and/or detected by SYRACO software; North Atlantic; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; seawater scale; total scale; Phytoplankton; Replicates; Salinity; Sample ID; South Atlantic; Pacific; Indian; Antarc*; Carbonic acid; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.767576; https://doi.org/10.1594/PANGAEA.767576

About one-third of the carbon dioxide (CO2) released into the atmosphere as a result of human activity has been absorbed by the oceans, where it partitions into the constituent ions of carbonic acid. This leads to ocean acidification, one of the major threats to marine ecosystems and particularly to calcifying organisms such as corals, foraminifera and coccolithophores. Coccolithophores are abundant phytoplankton that are responsible for a large part of modern oceanic carbonate production. Culture experiments investigating the physiological response of coccolithophore calcification to increased CO2 have yielded contradictory results between and even within species. Here we quantified the calcite mass of dominant coccolithophores in the present ocean and over the past forty thousand years, and found a marked pattern of decreasing calcification with increasing partial pressure of CO2 and concomitant decreasing concentrations of CO3. Our analyses revealed that differentially calcified species and morphotypes are distributed in the ocean according to carbonate chemistry. A substantial impact on the marine carbon cycle might be expected upon extrapolation of this correlation to predicted ocean acidification in the future. However, our discovery of a heavily calcified Emiliania huxleyi morphotype in modern waters with low pH highlights the complexity of assemblage-level responses to environmental forcing factors.