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Rapid and sustained surface ocean acidification during the Paleocene-Eocene Thermal Maximum

Donald E. Penman; Baerbel Hoenisch; Richard E. Zeebe; Ellen Thomas; James C. Zachos

Title:
Rapid and sustained surface ocean acidification during the Paleocene-Eocene Thermal Maximum
Author(s):
Penman, Donald E.
Hoenisch, Baerbel
Zeebe, Richard E.
Thomas, Ellen
Zachos, James C.
Date:
Type:
Articles
Department(s):
Lamont-Doherty Earth Observatory
Volume:
29
Persistent URL:
Book/Journal Title:
Paleoceanography
Abstract:
The Paleocene-Eocene Thermal Maximum (PETM) has been associated with the release of several thousands of petagrams of carbon (Pg C) as methane and/or carbon dioxide into the ocean-atmosphere system within ~10 kyr, on the basis of the co-occurrence of a carbon isotope excursion (CIE), widespread dissolution of deep sea carbonates, and global warming. In theory, this rapid carbon release should have severely acidified the surface ocean, though no geochemical evidence has yet been presented. Using boron-based proxies for surface ocean carbonate chemistry, we present the first observational evidence for a drop in the pH of surface and thermocline seawater during the PETM. Planktic foraminifers from a drill site in the North Pacific (Ocean Drilling Program Site 1209) show a ~0.8‰ decrease in boron isotopic composition (δ11B) at the onset of the event, along with a 30–40% reduction in shell B/Ca. Similar trends in δ11B are present in two lower-resolution records from the South Atlantic and Equatorial Pacific. These observations are consistent with significant, global acidification of the surface ocean lasting at least 70 kyr and requiring sustained carbon release. The anomalies in the B records are consistent with an initial surface pH drop of ~0.3 units, at the upper range of model-based estimates of acidification.
Subject(s):
Paleocene Geologic Epoch
Carbon dioxide
Ocean acidification
Chemical oceanography
Paleontology
Publisher DOI:
https://doi.org/10.1002/2014PA002621
Item views
90
Metadata:
text | xml
Suggested Citation:
Donald E. Penman, Baerbel Hoenisch, Richard E. Zeebe, Ellen Thomas, James C. Zachos, , Rapid and sustained surface ocean acidification during the Paleocene-Eocene Thermal Maximum, Columbia University Academic Commons, .

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