The residence time of Southern Ocean surface waters and the 100,000-year ice age cycle

Hasenfratz, Adam; Jaccard, Samuel; Martinez-Garcia, Alfredo; Sigman, Daniel M.; Hodell, David A.; Vance, Derek; Bernasconi, Stefano M.; Kleiven, Helga F.; Haumann, F. Alexander; Haug, Gerald H. (2019). The residence time of Southern Ocean surface waters and the 100,000-year ice age cycle. Science, 363(6431), pp. 1080-1084. American Association for the Advancement of Science 10.1126/science.aat7067

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From 1.25 million to 700,000 years ago, the ice age cycle deepened and lengthened from 41,000- to 100,000-year periodicity, a transition that remains unexplained. Using surface- and bottom-dwelling foraminifera from the Antarctic Zone of the Southern Ocean to reconstruct the deep-to-surface supply of water during the ice ages of the past 1.5 million years, we found that a reduction in deep water supply and a concomitant freshening of the surface ocean coincided with the emergence of the high-amplitude 100,000-year glacial cycle. We propose that this slowing of deep-to-surface circulation (i.e., a longer residence time for Antarctic surface waters) prolonged ice ages by allowing the Antarctic halocline to strengthen, which increased the resistance of the Antarctic upper water column to orbitally paced drivers of carbon dioxide release.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Hasenfratz, Adam and Jaccard, Samuel

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0036-8075

Publisher:

American Association for the Advancement of Science

Language:

English

Submitter:

Samuel Jaccard

Date Deposited:

25 Apr 2019 15:29

Last Modified:

22 Oct 2019 20:06

Publisher DOI:

10.1126/science.aat7067

PubMed ID:

30846597

BORIS DOI:

10.7892/boris.127688

URI:

https://boris.unibe.ch/id/eprint/127688

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