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

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TLDR
Continuous chemical proxy data spanning the last eight glacial cycles from the Dome C Antarctic ice core constrain winter sea-ice extent in the Indian Ocean, Southern Ocean biogenic productivity and Patagonian climatic conditions and observe large glacial–interglacial contrasts in iron deposition, which is infer reflects strongly changing Patagonia conditions.
Abstract
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.

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High-resolution carbon dioxide concentration record 650,000–800,000 years before present

TL;DR: It is found that atmospheric carbon dioxide is strongly correlated with Antarctic temperature throughout eight glacial cycles but with significantly lower concentrations between 650,000 and 750,000 yr before present, which extends the pre-industrial range of carbon dioxide concentrations during the late Quaternary by about 10 p.p.m.v.

Orbital and millenial antarctic climate variability over the last 800 000 years

TL;DR: A high-resolution deuterium profile is available along the entire European Project for Ice Coring in Antarctica Dome C ice core, extending this climate record back to marine isotope stage 20.2, ∼800,000 years ago.
Journal ArticleDOI

Saturation of the Southern Ocean CO2 Sink Due to Recent Climate Change

TL;DR: It is estimated that the Southern Ocean sink of CO2 has weakened between 1981 and 2004 by 0.08 petagrams of carbon per year per decade relative to the trend expected from the large increase in atmospheric CO2.
References
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Journal ArticleDOI

A Pliocene-Pleistocene stack of 57 globally distributed benthic δ18O records

TL;DR: In this paper, a 53-Myr stack (LR04) of benthic δ18O records from 57 globally distributed sites aligned by an automated graphic correlation algorithm is presented.

Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica

TL;DR: The recent completion of drilling at Vostok station in East Antarctica has allowed the extension of the ice record of atmospheric composition and climate to the past four glacial-interglacial cycles.
Journal ArticleDOI

Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica

TL;DR: The recent completion of drilling at Vostok station in East Antarctica has allowed the extension of the ice record of atmospheric composition and climate to the past four glacial-interglacial cycles as discussed by the authors.
Journal ArticleDOI

Oceanic phytoplankton, atmospheric sulphur, cloud albedo and climate

TL;DR: The major source of cloud-condensation nuclei (CCN) over the oceans appears to be dimethylsulphide, which is produced by planktonic algae in sea water and oxidizes in the atmosphere to form a sulphate aerosol as mentioned in this paper.
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