I/Ca evidence for upper ocean deoxygenation during the PETM

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doi: 10.1002/2014PA002702
Author(s): Zhou, Xiaoli; Thomas, Ellen; Rickaby, Rosalind E. M.; Winguth, Arne M. E.; Lu, Zunli
Author Affiliation(s): Primary:
Syracuse University, Department of Earth Sciences, Syracuse, NY, United States
Yale University, United States
University of Oxford, United Kingdom
University of Texas, Arlington, United States
Volume Title: Paleoceanography
Source: Paleoceanography, 29(10), p.964-975. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. NSF grants OCE-1232620 and OCE-1232413. 92 refs.; illus.
Summary: Anthropogenic global warming affects marine ecosystems in complex ways, and declining ocean oxygenation is a growing concern. Forecasting the geographical and bathymetric extent, rate, and intensity of future deoxygenation and its effects on oceanic biota, however, remains highly challenging because of the complex feedbacks in the Earth-ocean biota system. Information on past global warming events such as the Paleocene-Eocene Thermal Maximum (PETM, ∼55.5 Ma), a potential analog for present and future global warming, may help in such forecasting. Documenting past ocean deoxygenation, however, is hampered by the lack of sensitive proxies for past oceanic oxygen levels throughout the water column. As yet no evidence has been presented for pervasive deoxygenation in the upper water column through expansion of oxygen minimum zones (OMZs). We apply a novel proxy for paleoredox conditions, the iodine to calcium ratio (I/Ca) in bulk coarse fraction sediment and planktonic foraminiferal tests from pelagic sites in different oceans, and compared our reconstruction with modeled oxygen levels. The reconstructed iodate gradients indicate that deoxygenation occurred in the upper water column in the Atlantic, Indian Oceans, and possibly the Pacific Ocean, as well during the PETM, due to vertical and potentially lateral expansion of OMZs. Abstract Copyright (2014), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2014
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Alkaline earth metals; Anaerobic environment; Atlantic Ocean; Calcium; Cenozoic; East Pacific; Exmouth Plateau; Foraminifera; Halogens; I/Ca; ICP mass spectra; Indian Ocean; Invertebrata; Iodine; Kerguelen Plateau; Leg 113; Leg 119; Leg 122; Leg 143; Leg 208; Marine environment; Mass spectra; Maud Rise; Metals; Microfossils; Mid-Pacific Mountains; North Pacific; Northeast Pacific; ODP Site 1262; ODP Site 1263; ODP Site 690; ODP Site 738; ODP Site 762; ODP Site 865; Ocean Drilling Program; Pacific Ocean; Paleocene-Eocene Thermal Maximum; Paleoclimatology; Paleoecology; Paleoenvironment; Paleogene; Planktonic taxa; Productivity; Protista; South Atlantic; Southern Ocean; Spectra; Tertiary; Walvis Ridge; Weddell Sea
Coordinates: S283200 S271100 E0024700 E0013400
N182624 N182626 W1793320 W1793321
S650938 S650937 E0011218 E0011218
S624233 S624232 E0824715 E0824714
Record ID: 2015004445
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom