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

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doi: 10.1002/2014PA002621
Author(s): Penman, Donald E.; Hönisch, Bärbel; Zeebe, Richard E.; Thomas, Ellen; Zachos, James C.
Author Affiliation(s): Primary:
University of California at Santa Cruz, Santa Cruz, CA, United States
Other:
Lamont-Doherty Earth Observatory, United States
University of Hawaii at Manoa, United States
Yale University, United States
Volume Title: Paleoceanography
Source: Paleoceanography, 29(5), p.357-369. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. NSF Grant OCE-0903014, OCE09-02869, OCE12-20602, and OCE12-20554. 68 refs.; illus.
Summary: 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 ppm 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. Abstract Copyright (2014), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2014
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Acarinina soldadoensis; Acidification; Alkaline earth metals; Atlantic Ocean; B-11/B-10; B/Ca; Boron; C-13/C-12; Calcium; Carbon; Cenozoic; Climate change; East Pacific; Foraminifera; Invertebrata; Isotope ratios; Isotopes; Leg 143; Leg 198; Leg 208; Marine environment; Metals; Microfossils; Mid-Pacific Mountains; Morozovella velascoensis; North Pacific; Northeast Pacific; Northwest Pacific; O-18/O-16; ODP Site 1209; ODP Site 1263; ODP Site 865; Ocean Drilling Program; Oxygen; PH; Pacific Ocean; Paleo-oceanography; Paleocene-Eocene Thermal Maximum; Paleoclimatology; Paleoenvironment; Paleogene; Planktonic taxa; Protista; Shatsky Rise; South Atlantic; Stable isotopes; Tertiary; Walvis Ridge; West Pacific
Coordinates: S283200 S283200 E0024700 E0024700
N182624 N182626 W1793320 W1793321
N323900 N324000 E1583100 E1583000
Record ID: 2014084683
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom