Increased nutrient supply to the Southern Ocean during the Holocene and its implications for the pre-industrial atmospheric CO2 rise

Studer, Anja S.; Sigman, Daniel M.; Martinez-Garcia, Alfredo; Thöle, Lena; Michel, Elisabeth; Jaccard, Samuel; Lippold, Jörg; Mazaud, Alain; Wang, Xingchen T.; Robinson, Laura F.; Adkins, Jess F.; Haug, Gerald H. (2018). Increased nutrient supply to the Southern Ocean during the Holocene and its implications for the pre-industrial atmospheric CO2 rise. Nature geoscience, 11(10), pp. 756-760. Nature Publishing Group 10.1038/s41561-018-0191-8

[img] Text
Studer et al., 18.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (1MB) | Request a copy

A rise in the atmospheric CO2 concentration of ~20 parts per million over the course of the Holocene has long been recognized as exceptional among interglacials and is in need of explanation. Previous hypotheses involved natural or anthropogenic changes in terrestrial biomass, carbonate compensation in response to deglacial outgassing of oceanic CO2, and enhanced shallow water carbonate deposition. Here, we compile new and previously published fossil-bound nitrogen isotope records from the Southern Ocean that indicate a rise in surface nitrate concentration through the Holocene. When coupled with increasing or constant export production, these data suggest an acceleration of nitrate supply to the Southern Ocean surface from underlying deep water. This change would have weakened the ocean’s biological pump that stores CO2 in the ocean interior, possibly explaining the Holocene atmospheric CO2 rise. Over the Holocene, the circum-North Atlantic region cooled, and the formation of North Atlantic Deep Water appears to have slowed. Thus, the ‘seesaw’ in deep ocean ventilation between the North Atlantic and the Southern Ocean that has been invoked for millennial-scale events, deglaciations and the last interglacial period may have also operated, albeit in a more gradual form, over the Holocene.

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:

Thöle, Lena and Jaccard, Samuel

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

1752-0894

Publisher:

Nature Publishing Group

Language:

English

Submitter:

Samuel Jaccard

Date Deposited:

02 Oct 2018 12:44

Last Modified:

07 Oct 2018 02:30

Publisher DOI:

10.1038/s41561-018-0191-8

BORIS DOI:

10.7892/boris.120243

URI:

https://boris.unibe.ch/id/eprint/120243

Actions (login required)

Edit item Edit item
Provide Feedback