Further Observations Of A Decreasing Atmospheric Co2 Uptake Capacity In The Canada Basin (Arctic Ocean) Due To Sea Ice Loss

B. G. T. Else (1) , R. J. Galley (2) , B. Lansard (3, 4) , D. G. Barber (5) , K. Brown (6) , L. A. Miller (7) , A. Mucci (8) , T. N. Papakyriakou (2) , J. E. Tremblay (9) , S. Rysgaard (2)

1 CEOS
2 CEOS
3 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
4 OCEANIS - Océan et Interfaces
5 CEOS
6 EOS - Department of Earth and Ocean Sciences [Vancouver]
7 Institute of Ocean Sciences, Fisheries and Oceans Canada
8 GEOTOP and Department of Earth and Planetary Sciences
9 Department de Biologie

Using data collected in 2009, we evaluated the potential for the southeastern Canada Basin (Arctic Ocean) to act as an atmospheric CO2 sink under the summertime ice-free conditions expected in the near future. Beneath a heavily decayed ice cover, we found surprisingly high pCO(2sw) (similar to 290-320 mu atm), considering that surface water temperatures were low and the influence of ice melt was strong. A simple model simulating melt of the remaining ice and exposure of the surface water for 100 days revealed a weak capacity for atmospheric CO2 uptake (mean flux: -2.4mmol m(-2) d(-1)), due largely to warming of the shallow mixed layer. Our results confirm a previous finding that the Canada Basin is not a significant sink of atmospheric CO2 under summertime ice-free conditions and that increased ventilation of the surface mixed layer due to sea ice loss is weakening the sink even further.

Mots clés: CARBONIC-ACID; FRESH-WATER; ACIDIFICATION; DISSOCIATION; CONSTANTS; SEAWATER

Domaines: Océan, Atmosphère

B. G. T. Else, R. J. Galley, B. Lansard, D. G. Barber, K. Brown, et al.. Further Observations Of A Decreasing Atmospheric Co2 Uptake Capacity In The Canada Basin (Arctic Ocean) Due To Sea Ice Loss. Geophysical Research Letters, 2013, 40 (6), pp.1132-1137. ⟨10.1002/grl.50268⟩. ⟨hal-00984553v2⟩