Southern Ocean CO2 sink: The contribution of the sea ice. Issue 9 (22nd September 2014)

• Record Type: Journal Article
• Authors: Delille, Bruno; Vancoppenolle, Martin; Geilfus, Nicolas‐Xavier; Tilbrook, Bronte; Lannuzel, Delphine; Schoemann, Véronique; Becquevort, Sylvie; Carnat, Gauthier; Delille, Daniel; Lancelot, Christiane; Chou, Lei; Dieckmann, Gerhard S.; Tison, Jean‐Louis
• Is Part Of: Journal of geophysical research. Volume 119:Issue 9(2014:Sep.)
• Page Start: 6340
• Page End: 6355
• Publication Date: 2014-09-22
• Subjects: Oceanography -- Periodicals; 551.4605
• DOI: 10.1002/2014JC009941
• Languages: English
• ISSNs: 2169-9275

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>We report first direct measurements of the partial pressure of CO₂ (pCO₂) within Antarctic pack sea ice brines and related CO₂ fluxes across the air‐ice interface. From late winter to summer, brines encased in the ice change from a CO₂ large oversaturation, relative to the atmosphere, to a marked undersaturation while the underlying oceanic waters remains slightly oversaturated. The decrease from winter to summer of pCO₂ in the brines is driven by dilution with melting ice, dissolution of carbonate crystals, and net primary production. As the ice warms, its permeability increases, allowing CO₂ transfer at the air‐sea ice interface. The sea ice changes from a transient source to a sink for atmospheric CO₂. We upscale these observations to the whole Antarctic sea ice cover using the NEMO‐LIM3 large‐scale sea ice‐ocean and provide first estimates of spring and summer CO₂ uptake from the atmosphere by Antarctic sea ice. Over the spring‐summer period, the Antarctic sea ice cover is a net sink of atmospheric CO₂ of 0.029 Pg C, about 58% of the estimated annual uptake from the Southern Ocean. Sea ice then contributes significantly to the sink of CO₂ of the Southern Ocean.</p> </abstract>