Poorly ventilated deep ocean at the Last Glacial Maximum inferred from carbon isotopes: A data-model comparison study
Laurie Menviel,Jimin Yu,Fortunat Joos,Anne Mouchet,Anne Mouchet,Anne Mouchet,KA Meissner,Matthew H. England +7 more
TLDR
In this article, the role of ocean circulation in setting the LGM oceanic δ¹³C distribution was investigated, and the authors found that the change in mean ocean δ ¹ ³C change can be explained by a 378 ± 88 Gt C(2σ) smaller LGM terrestrial carbon reservoir compared to the Holocene.Abstract:
Atmospheric CO₂ was ~90 ppmv lower at the Last Glacial Maximum (LGM) compared to the late Holocene, but the mechanisms responsible for this change remain elusive. Here we employ a carbon isotope-enabled Earth System Model to investigate the role of ocean circulation in setting the LGM oceanic δ¹³C distribution, thereby improving our understanding of glacial/interglacial atmospheric CO₂ variations. We find that the mean ocean δ¹³C change can be explained by a 378 ± 88 Gt C(2σ) smaller LGM terrestrial carbon reservoir compared to the Holocene. Critically, in this model, differences in the oceanic δ¹³C spatial pattern can only be reconciled with a LGM ocean circulation state characterized by a weak (10–15 Sv) and relatively shallow (2000–2500 m) North Atlantic Deep Water cell, reduced Antarctic Bottom Water transport (≤10 Sv globally integrated), and relatively weak (6–8 Sv) and shallow (1000–1500 m) North Pacific Intermediate Water formation. This oceanic circulation state is corroborated by results from the isotope-enabled Bern3D ocean model and further confirmed by high LGM ventilation ages in the deep ocean, particularly in the deep South Atlantic and South Pacific. This suggests a poorly ventilated glacial deep ocean which would have facilitated the sequestration of carbon lost from the terrestrial biosphere and atmosphere.read more
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Southern Hemisphere westerlies as a driver of the early deglacial atmospheric CO 2 rise
Laurie Menviel,Laurie Menviel,Paul Spence,Jimin Yu,Matthew A. Chamberlain,Richard J. Matear,Katrin J. Meissner,Matthew H. England +7 more
TL;DR: It is shown that Southern Ocean convection driven by intensified Southern Hemisphere westerlies during Heinrich stadial 1 can explain the abrupt pCO2 rise and changes in atmosphere and ocean carbon isotopes.
Journal ArticleDOI
Response of a comprehensive climate model to a broad range of external forcings: relevance for deep ocean ventilation and the development of late Cenozoic ice ages
TL;DR: In this paper, a broad view on the influences of CO2, orbital forcing and ice sheet size according to a comprehensive Earth system model was provided, by integrating the model to equilibrium under 40 different combinations of the three external forcings.
Journal ArticleDOI
Stable carbon isotopes in paleoceanography: atmosphere, oceans, and sediments
TL;DR: The application of stable carbon isotope ratios in ocean water and biogenic carbonates as proxies in paleoceanography, including the atmospheric and sedimentary reservoirs oceanic carbon is in exchange with, is reviewed in this paper.
Journal ArticleDOI
Weak overturning circulation and high Southern Ocean nutrient utilization maximized glacial ocean carbon
TL;DR: In this article, the authors simulate the modern and glacial ocean using a coupled physical-biogeochemical, global, three-dimensional model constrained simultaneously by δ 13 C, radiocarbon, and δ 15 N to explore the effects of AMOC differences and Southern Ocean iron fertilization on the distributions of these isotopes and ocean carbon storage.
References
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Journal ArticleDOI
Carbon isotope fractionation between dissolved bicarbonate and gaseous carbon-dioxide
TL;DR: In this paper, the stable carbon isotope fractionation between gaseous CO 2 and dissolved bicarbonate has been measured from 5 to 25°C by a method of high precision.
Journal ArticleDOI
Glacial/interglacial variations in atmospheric carbon dioxide
Daniel M. Sigman,Edward A. Boyle +1 more
TL;DR: A version of the hypothesis that the whole-ocean reservoir of algal nutrients was larger during glacial times, strengthening the biological pump at low latitudes, where these nutrients are currently limiting is presented.
Journal ArticleDOI
Deepwater source variations during the last climatic cycle and their impact on the global deepwater circulation
J.-C. Duplessy,N.J. Shackleton,Richard G. Fairbanks,Laurent Labeyrie,Delia W Oppo,Nejib Kallel +5 more
TL;DR: In this paper, a detailed reconstruction of the geographic distribution of ∂13C in benthic foraminifera in the Atlantic Ocean during the last glacial maximum was presented.
Journal ArticleDOI
Modelling West Antarctic ice sheet growth and collapse through the past five million years
David Pollard,Robert M. DeConto +1 more
TL;DR: A combined ice sheet/ice shelf model capable of high-resolution nesting with a new treatment of grounding-line dynamics and ice-shelf buttressing is used to simulate Antarctic ice sheet variations over the past five million years, indicating a long-term trend from more frequently collapsed to more glaciated states.
Journal ArticleDOI
Effect of seawater carbonate concentration on foraminiferal carbon and oxygen isotopes
TL;DR: In this paper, the authors reported experimental measurements on living symbiotic and non-symbiotic plankton foraminifera (Orbulina universa and Globigerina bulloides respectively) showing that the 13C/12C and 18O/16O ratios of the calcite shells decrease with increasing seawater [CO32−].
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