The nature of deep overturning and reconfigurations of the silicon cycle across the last deglaciation

Type Article
Date 2020-03
Language English
Author(s) Dumont M.1, 2, Pichevin L.1, Geibert W.3, Crosta X.4, Michel E.5, Moreton S.6, Dobby K.1, Ganeshram R.1
Affiliation(s) 1 : School of Geosciences, University of Edinburgh, Edinburgh, UK
2 : School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
3 : Alfred Wegener Institute, Bremerhaven, Germany
4 : UMR 5805 EPOC, Universite de Bordeaux, Bordeaux, France
5 : Laboratoire des Sciences du Climat et l’Environnement/Institute Pierre-Simon Laplace, Laboratoire CNRS-CEA-UVSQ, Gif-sur-Yvette, France
6 : Scottish Universities Environmental Research Centre, East Kilbride, UK
Source Nature Communications (2041-1723) (Springer Science and Business Media LLC), 2020-03 , Vol. 11 , N. 1 , P. 1534 (11p.)
DOI 10.1038/s41467-020-15101-6
WOS© Times Cited 4
Abstract

Changes in ocean circulation and the biological carbon pump have been implicated as the drivers behind the rise in atmospheric CO2 across the last deglaciation; however, the processes involved remain uncertain. Previous records have hinted at a partitioning of deep ocean ventilation across the two major intervals of atmospheric CO2 rise, but the consequences of differential ventilation on the Si cycle has not been explored. Here we present three new records of silicon isotopes in diatoms and sponges from the Southern Ocean that together show increased Si supply from deep mixing during the deglaciation with a maximum during the Younger Dryas (YD). We suggest Antarctic sea ice and Atlantic overturning conditions favoured abyssal ocean ventilation at the YD and marked an interval of Si cycle reorganisation. By regulating the strength of the biological pump, the glacial–interglacial shift in the Si cycle may present an important control on Pleistocene CO2 concentrations.

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