Rapid marine oxygen variability : Driver of the Late Ordovician mass extinction

Summary, in English

The timing and connections between global cooling, marine redox conditions, and biotic turnover are underconstrained for the Late Ordovician. The second most severe mass extinction occurred at the end of the Ordovician period, resulting in ~85% loss of marine species between two extinction pulses. As the only “Big 5” extinction that occurred during icehouse conditions, this interval is an important modern analog to constrain environmental feedbacks. We present a previously unexplored thallium isotope records from two paleobasins that record global marine redox conditions and document two distinct and rapid excursions suggesting vacillating (de)oxygenation. The strong temporal link between these perturbations and extinctions highlights the possibility that dynamic marine oxygen fluctuations, rather than persistent, stable global anoxia, played a major role in driving the extinction. This evidence for rapid oxygen changes leading to mass extinction has important implications for modern deoxygenation and biodiversity declines.

• Author: Nevin P. Kozik; Seth A. Young; Sean M. Newby; Mu Liu; Daizhao Chen; Emma U. Hammarlund; David P.G. Bond; Theodore R. Them; Jeremy D. Owens
• Department/s: StemTherapy: National Initiative on Stem Cells for Regenerative Therapy; Molecular Evolution; Lithosphere and Biosphere Science; Division of Translational Cancer Research
• Publishing year: 2022-11
• Language: English
• Publication/Series: Science Advances
• Volume: 8
• Issue: 46
• Links: http://dx.doi.org/10.1126/sciadv.abn8345
• Document type: Journal article
• Publisher: American Association for the Advancement of Science (AAAS)
• Topic: Zoology
• Status: Published
• Research group: Molecular Evolution
• ISBN/ISSN/Other: ISSN: 2375-2548