Gases in sea ice: Update of recent findings, caveats and open questions

Sea ice exchanges gases with the atmosphere including climate and ozone-depleting gases We will rapidly present a state of the art of current large scale assessment of spring and summer uptake of atmospheric CO2. We will challenge these assessments with 1) new evidence of significant winter CO2 release for winter experiments 2) role of bubbles formation and transport within sea ice 3) impact of biofilm. Finally, comparison of air-ice fluxes derived from automated chamber and micrometeorological method and, mechanistic and box models show significant discrepancies that suggest that the contribution of sea ice to the air-ocean fluxes of CO2 remain an open question. We will also sea ice contribution to the fluxes of other gases as CH4, N2O, DMS and VOC