North Atlantic versus Southern Ocean contributions to a deglacial surge in deep ocean ventilation

Past glacial-interglacial climate transitions were accompanied by millennial-scale pulses in atmospheric CO2 that are widely thought to have resulted from the release of CO2 via the Southern Ocean. However, direct proxy evidence for a Southern Ocean role in regulating past ocean-atmosphere CO2 excha...

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Bibliographic Details
Published in:Geology (Boulder) 2013-06, Vol.41 (6), p.667-670
Main Authors: Skinner, L. C, Scrivner, A. E, Vance, D, Barker, S, Fallon, S, Waelbroeck, C
Format: Article
Language:English
Subjects:
air-sea interface
Atlantic Ocean
Carbon cycle
Carbon dioxide
Cenozoic
chemostratigraphy
Continental interfaces, environment
cores
Glaciers
isotope ratios
isotopes
Marine
marine sediments
metals
Nd-144/Nd-143
neodymium
ocean circulation
Ocean, Atmosphere
Ocean-atmosphere interaction
Oceans
paleo-oceanography
paleocurrents
paleoenvironment
Pleistocene
Quaternary
Quaternary geology
rare earths
Sciences of the Universe
sediments
South Atlantic
Southern Ocean
stable isotopes
tracers
ventilation
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Summary:Past glacial-interglacial climate transitions were accompanied by millennial-scale pulses in atmospheric CO2 that are widely thought to have resulted from the release of CO2 via the Southern Ocean. However, direct proxy evidence for a Southern Ocean role in regulating past ocean-atmosphere CO2 exchange is scarce. Here we use combined radiocarbon and neodymium isotope measurements from the last deglaciation to confirm greatly enhanced overturning and/or air-sea exchange rates relative to today, in particular during the Bolling-Allerod warm interval. We show that this deglacial pulse in ocean ventilation was not driven by the North Atlantic overturning alone, and must have involved an increase in the ventilation of southern-sourced deep waters. Our results thus confirm the removal of a physical and/or dynamical barrier to effective air-sea (CO2) exchange in the Southern Ocean during deglaciation, and highlight the Antarctic region as a key locus for global climate/carbon-cycle feedbacks.
ISSN:0091-7613
1943-2682
DOI:10.1130/G34133.1