Sea ice pCO 2 dynamics and air-ice CO 2 fluxes during the Sea Ice Mass Balance in the Antarctic (SIMBA) experiment - Bellingshausen Sea, Antarctica

• Published in: The Cryosphere
• Main Authors: Geilfus, Nicolas-Xavier, Tison, J.-L., Ackley, S.F., Galley, R.J., Rysgaard, Søren, Miller, L.A., Delille, B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2014
• Subjects: Antarctic; Bellingshausen Sea; The Antarctic; Antarc*; Antarctica; Sea ice; The Cryosphere; The Cryosphere Discussions
• Online Access: https://pure.au.dk/portal/da/publications/sea-ice-pco2-dynamics-and-airice-co2-fluxes-during-the-sea-ice-mass-balance-in-the-antarctic-simba-experiment--bellingshausen-sea-antarctica(47fbbcef-1751-4032-9856-ac2fad788812).html; https://doi.org/10.5194/tc-8-2395-2014; https://pure.au.dk/ws/files/83931885/Geilfus_et_al_2014_SIMBA.pdf

Temporal evolution of pCO2 profiles in sea ice in the Bellingshausen Sea, Antarctica, in October 2007 shows physical and thermodynamic processes controls the CO2 sys- tem in the ice. During the survey, cyclical warming and cool- ing strongly influenced the physical, chemical, and thermo- dynamic properties of the ice cover. Two sampling sites with contrasting characteristics of ice and snow thickness were sampled: one had little snow accumulation (from 8 to 25 cm) and larger temperature and salinity variations than the sec- ond site, where the snow cover was up to 38 cm thick and therefore better insulated the underlying sea ice. We show that each cooling/warming event was associated with an in- crease/decrease in the brine salinity, total alkalinity (TA), to- tal dissolved inorganic carbon (T CO2), and in situ brine and bulk ice CO2 partial pressures (pCO2). Thicker snow covers reduced the amplitude of these changes: snow cover influ- ences the sea ice carbonate system by modulating the temper- ature and therefore the salinity of the sea ice cover. Results indicate that pCO2 was undersaturated with respect to the at- mosphere both in the in situ bulk ice (from 10 to 193 μatm) and brine (from 65 to 293 μatm), causing the sea ice to act as a sink for atmospheric CO2 (up to 2.9 mmol m−2 d−1), despite supersaturation of the underlying seawater (up to 462 μatm).