Decrease in the CO2 Uptake Capacity in an Ice-Free Arctic Ocean Basin

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Science  22 Jul 2010:
DOI: 10.1126/science.1189338


It has been predicted that the Arctic Ocean will sequester much greater amounts of carbon dioxide (CO2) from the atmosphere due to sea ice melt and increasing primary productivity (1, 2). However, this prediction was made based on observations from either highly productive ocean margins or ice-covered basins prior to the recent major ice retreat (3, 4). We report here a high-resolution survey of sea surface CO2 level across the Canada Basin, showing a great increase over earlier observations. Rapid CO2 invasion from the atmosphere and low biological CO2 drawdown are the main causes for the higher CO2, which also acts as a barrier to further CO2 invasion. Contrary to the current view, we predict that the Arctic Ocean basin will not become a large atmospheric CO2 sink under ice-free conditions.