The fate of pelagic CaCO₃ production in a high CO₂ ocean: A model study

Marion Gehlen (1) , R. Gangstø (1) , Birgit Schneider (1) , Laurent Bopp (1) , Olivier Aumont (2) , Christian Éthé (1)

1 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
2 LOCEAN - Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques

This model study addresses the change in pelagic calcium carbonate production (CaCO₃, as calcite in the model) and dissolution in response to rising atmospheric CO₂. The parameterization of CaCO₃ production includes a dependency on the saturation state of seawater with respect to calcite. It was derived from laboratory and mesocosm studies on particulate organic and inorganic carbon production in Emiliania huxleyi as a function of pCO₂. The model predicts values of CaCO₃ production and dissolution in line with recent estimates. The effect of rising pCO₂ on CaCO₃ production and dissolution was quantified by means of model simulations forced with atmospheric CO₂ increasing at a rate of 1% per year from 286 ppm to 1144 ppm. The simulation predicts a decrease of CaCO₃ production by 27%. The combined change in production and dissolution of CaCO₃ yields an excess uptake of CO₂ from the atmosphere by the ocean of 5.9 GtC.

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Astrophysique [astro-ph]; Interfaces continentales, environnement; Océan, Atmosphère; Sciences de la Terre

Marion Gehlen, R. Gangstø, Birgit Schneider, Laurent Bopp, Olivier Aumont, et al.. The fate of pelagic CaCO₃ production in a high CO₂ ocean: A model study. 2008. ⟨hal-00330230⟩