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

• Published in: Nature
• Main Authors: Wolff, E., Fischer, Hubertus, Fundel, F., Ruth, U., Twarloh, B., Littot, G., Mulvaney, R., Röthlisberger, R., de Angelis, Martine, Boutron, Claude F., Hansson, M., Jonsell, U., Hutterli, M. A., Lambert, F., Kaufmann, P., Stauffer, Bernard, Stocker, Thomas F., Steffensen, J. P., Bigler, M., Siggaard-Andersen, M.-L., Udisti, Roberto, Becagli, Silvia, Castellano, E., Severi, Mirko, Wagenbach, D., Barbante, Carlo, Gabrielli, Paolo, Gaspari, Vania
• Other Authors: British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Abteilung Klinische Sozialmedizin, Berufs- und Umweltdermatologie, Universität Heidelberg Heidelberg = Heidelberg University, Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physical Geography and Quaternary Geology, Stockholm University, Climate and Environmental Physics Bern (CEP), Physikalisches Institut Bern, Universität Bern / University of Bern (UNIBE)-Universität Bern / University of Bern (UNIBE), Geophysics and Water Resources, Section for Geology Copenhagen, Department of Geosciences and Natural Resource Management Copenhagen (IGN), Faculty of Science Copenhagen, University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)-Faculty of Science Copenhagen, University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)-Department of Geosciences and Natural Resource Management Copenhagen (IGN), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Department of Chemistry, Università degli Studi di Firenze = University of Florence = Université de Florence (UniFI), Institut für Umweltphysik Heidelberg, Institute for the Dynamics of Environmental Processes-CNR, University of Ca’ Foscari Venice, Italy, Environmental Sciences Department, European Project for Ice Coring in Antarctica (EPICA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Antarctic; Indian; Patagonia; Southern Ocean; Antarc*; ice core; Sea ice
• Online Access: https://insu.hal.science/insu-00375835; https://doi.org/10.1038/nature04614

International audience Sea ice and dust flux increased greatly in the Southern Ocean during the last glacial period. Palaeorecords provide contradictory evidence about marine productivity in this region, but beyond one glacial cycle, data were sparse. Here we present 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. We found that maximum sea-ice extent is closely tied to Antarctic temperature on multi-millennial timescales, but less so on shorter timescales. Biological dimethylsulphide emissions south of the polar front seem to have changed little with climate, suggesting that sulphur compounds were not active in climate regulation. We observe large glacial–interglacial contrasts in iron deposition, which we 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. We observe no changes in internal climatic feedbacks that could have caused the change in amplitude of Antarctic temperature variations observed 440,000 years ago.