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Etendue de la calotte glaciaire australe, productivité et flux de fer pendant les huit derniers cycle glaciaires.

Southern Ocean sea ice extent, productivity and iron flux over the past eight glacial cycles.

Auteurs : WOLFF E. W., FISCHER H., FUNDEL F., et al.

Type d'article : Article

Résumé

The article presents continuous chemical proxy data spanning the last eight glacial cycles (740 000 years) from the Dome C Antarctic ice core. These data constrain winter sea-ice extent in the Indian Ocean, Southern Ocean biogenic productivity and Patagonian climatic conditions. The authors found that maximum sea-ice extent is closely tied to Antartic temperature on multi-millenial timescales, but less so on shorter timescales. Biological DMSO emissions south of the polar front seem to have changed little with climate, suggesting that sulphur compounds were not active in climate regulation. They observe large glacial-interglacial contrasts in iron deposition, which they infer reflects strongly changing Patagonian conditions. During glacial terminations, changes in Patagonia apparently preceded sea-ice reduction, indicating that multiple mechanisms may be responsible for different phases of CO2 increase during glacial terminations. The authors observe no changes in internal climatic feedbacks that could have caused the change in amplitude of Antarctic temperature variations observed 440 000 years ago.

Détails

  • Titre original : Southern Ocean sea ice extent, productivity and iron flux over the past eight glacial cycles.
  • Identifiant de la fiche : 2006-2114
  • Langues : Anglais
  • Sujet : Environnement, Généralités
  • Source : Nature - vol. 440 - n. 7083
  • Date d'édition : 23/03/2006

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