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Biogeosciences An interactive open-access journal of the European Geosciences Union
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Volume 13, issue 14 | Copyright
Biogeosciences, 13, 4205-4218, 2016
https://doi.org/10.5194/bg-13-4205-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 25 Jul 2016

Research article | 25 Jul 2016

Sedimentary response to sea ice and atmospheric variability over the instrumental period off Adélie Land, East Antarctica

Philippine Campagne1,2,3,4, Xavier Crosta1, Sabine Schmidt1, Marie Noëlle Houssais2, Olivier Ther1, and Guillaume Massé2,3 Philippine Campagne et al.
  • 1EPOC, UMR CNRS 5805, Université de Bordeaux, Allée Geoffroy St Hilaire, 33615 Pessac, France
  • 2LOCEAN, UMR CNRS/UPCM/IRD/MNHN 7159, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris, France
  • 3TAKUVIK, UMI 3376 UL/CNRS, Département de Biologie, Université Laval, G1V 0A6 Quebec (Quebec), Canada
  • 4Québec-Océan, Université Laval, 1045 Avenue de la Médecine, G1V 0A6 Quebec (Quebec), Canada

Abstract. Diatoms account for a large proportion of primary productivity in Antarctic coastal and continental shelf zones. Diatoms, which have been used for a long time to infer past sea surface conditions in the Southern Ocean, have recently been associated with diatom-specific biomarkers (highly branched isoprenoids, HBI). Our study is one of the few sedimentary research projects on diatom ecology and associated biomarkers in the Antarctic seasonal sea ice zone. To date, the Adélie Land region has received little attention, despite evidence for the presence of high accumulation of laminated sediment, allowing for finer climate reconstructions and sedimentary process studies. Here we provide a sequence of seasonally to annually laminated diatomaceous sediment from a 72.5cm interface core retrieved on the continental shelf off Adélie Land, covering the 1970–2010CE period. Investigations through statistical analyses of diatom communities, diatom-specific biomarkers and major element abundances document the relationships between these proxies at an unprecedented resolution. Additionally, comparison of sedimentary records to meteorological data monitored by automatic weather station and satellite derived sea ice concentrations help to refine the relationships between our proxies and environmental conditions over the last decades. Our results suggest a coupled interaction of the atmospheric and sea surface variability on sea ice seasonality, which acts as the proximal forcing of siliceous productivity at that scale.

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Diatoms and biomarkers have been recently used for palaeoclimate reconstructions in the Southern Ocean. Few sediment-based ecological studies have investigated their relationships with environmental conditions. Here, we compare high-resolution sedimentary records with meteorological data to study relationships between our proxies and recent atmospheric and sea surface changes. Our results indicate that coupled wind pattern and sea surface variability act as the proximal forcing at that scale.
Diatoms and biomarkers have been recently used for palaeoclimate reconstructions in the Southern...
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