Shifting Antarctic Circumpolar Current over the past 1.9 million years
Author Information
Author(s): Aidan Starr, Ian R. Hall, Stephen Barker, Alexandra Nederbragt, Lindsey Owen, Sidney R. Hemming
Primary Institution: School of Earth and Environmental Sciences, Cardiff University
Hypothesis
How has the Antarctic Circumpolar Current (ACC) changed over the past 1.9 million years?
Conclusion
The study shows that shifts in the Antarctic Circumpolar Current are closely linked to Southern Ocean upwelling during warm intervals in Earth's past.
Supporting Evidence
- Reconstructed flow speed variability reveals systematic glacial-interglacial variations in the strength of ACC jets.
- Warmer-than-present 'super-interglacials' show a slowdown in midlatitude ACC flow.
- Poleward strengthening of the ACC is implied by faster flow at higher latitudes.
Takeaway
The Antarctic Circumpolar Current, the world's largest ocean current, has changed its flow patterns over millions of years, affecting how carbon dioxide levels in the atmosphere rise and fall.
Methodology
The study reconstructed near-bottom flow speed variability in the Southern Ocean using sediment core samples and analyzed stable carbon isotope gradients.
Limitations
The reconstruction is limited to specific sediment core sites, which may not capture the full variability of the ACC.
Digital Object Identifier (DOI)
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