Carbon dioxide dynamics and related air-ice fluxes in Antarctic sea ice

By controlling sea ice porosity, and subsequently gas transfer and nutrients supply, temperature appears to be one of the main controlling factors on the CO2 dynamics. Ice below the temperature threshold of about -5°C (winter type stations) displays the higher pCO2 values, whilst the warmer, more porous, ice ("spring" type station) favours the set up of primary production and hence, shows the lowest pCO2 values. Strong gradients of pCO2 have been observed at the air-ice interface either positive or negative, depending primarily on the temperature profile. These gradients can drive exchanges of CO2 (measured with the chamber technique) up to 2.0 mmol.m-2.d-1, at the air-ice interface depending on the snow cover and the ice temperature.