Insignificant buffering capacity of Antarctic shelf carbonates

We combined data sets of measured sedimentary CaCO3 and satellite-derived pelagic primary production to parameterize the relation between CaCO3 content on the Antarctic shelves and primary production in the overlying water column. CaCO3 content predicted in this way was in good agreement with the measured data. The parameterization was then used to chart CaCO3 content on the Antarctic shelves all around the Antarctic, using the satellite-derived primary production. The total inventory of CaCO3 in the bioturbated layer of Antarctic shelf sediments was estimated to be 0.5 Pg C. This quantity is comparable to the total CO2 uptake by the Southern Ocean in only one to a few years (dependent on the uptake estimate and area considered), indicating that the dissolution of these carbonates will neither delay ocean acidification in this area nor augment the Southern Ocean CO2 uptake capacity.

Key Points

  • Sedimentary CaCO3 can be predicted from Primary Production in the water column
  • The inventory of CaCO3 in surface sediments on Antarctic shelves is 0.5 Pg C
  • Dissolution of CaCO3 cannot buffer pH or CO2 in the Southern Ocean

Hauck J., Arrigo K. R., Hoppema M., van Dijken G., Völker C. D. & Wolf-Gladrow D. A., in press. Insignificant buffering capacity of Antarctic shelf carbonates. Global Biogeochemical Cycles. doi:10.1029/2011GB004211. Article (subscription required).

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