Paleoceanographic Insights on Recent Oxygen Minimum Zone Expansion: Lessons for Modern Oceanography

Type Article
Date 2015-01
Language English
Author(s) Moffitt Sarah E.1, 2, Moffitt Russell A.3, Sauthoff Wilson4, Davis Catherine V.1, 4, Hewett Kathryn5, Hill Tessa M.1, 4
Affiliation(s) 1 : Univ Calif Davis, Bodega Marine Lab, Bodega Bay, CA 94923 USA.
2 : Univ Calif Davis, Grad Grp Ecol, Davis, CA 95616 USA.
3 : Marine Conservat Inst, Glen Ellen, CA USA.
4 : Univ Calif Davis, Dept Earth & Planetary Sci, Davis, CA 95616 USA.
5 : Univ Calif Davis, Dept Civil & Environm Engn, Davis, CA 95616 USA.
Source Plos One (1932-6203) (Public Library Science), 2015-01 , Vol. 10 , N. 1 , P. e0115246
DOI 10.1371/journal.pone.0115246
WOS© Times Cited 76
Abstract Climate-driven Oxygen Minimum Zone (OMZ) expansions in the geologic record provide an opportunity to characterize the spatial and temporal scales ofOMZ change. Here we investigate OMZ expansion through the global- scale warming event of the most recent deglaciation (18- 11 ka), an event with clear relevance to understanding modern anthropogenic climate change. Deglacial marine sediment records were compiled to quantify the vertical extent, intensity, surface area and volume impingements of hypoxic waters upon continental margins. By integrating sediment records (183-2,309 meters below sea level; mbsl) containing one or more geochemical, sedimentary or microfossil oxygenation proxies integrated with analyses of eustatic sea level rise, we reconstruct the timing, depth and intensity of seafloor hypoxia. The maximum vertical OMZ extent during the deglaciation was variable by region: Subarctic Pacific (similar to 600-2,900 mbsl), California Current (similar to 330-1,500 mbsl), Mexico Margin (similar to 330-830 mbsl), and the Humboldt Current and Equatorial Pacific (similar to 110-3,100 mbsl). The timing ofOMZ expansion is regionally coherent but not globally synchronous. Subarctic Pacific and California Current continental margins exhibit tight correlation to the oscillations of Northern Hemisphere deglacial events (Termination IA, Bolling-Allerod, Younger Dryas and Termination IB). Southern regions (Mexico Margin and the Equatorial Pacific and Humboldt Current) exhibit hypoxia expansion prior to Termination IA (similar to 14.7 ka), and no regional oxygenation oscillations. Our analyses provide new evidence for the geographically and vertically extensive expansion of OMZs, and the extreme compression of upper-ocean oxygenated ecosystems during the geologically recent deglaciation.
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