In the first study of its kind, geochemical evidence left behind in marine limestone sediment from Quebec’s Anticosti Island suggests a mass extinction that occurred more than 450 million years ago was caused by a period of global cooling that led to the world’s oceans abruptly losing life-supporting oxygen. The Late Ordovician Mass Extinction was the first of five mass-extinction events that Earth has experienced, and saw 85 per cent of marine life go extinct. The results suggest the potential severity of marine anoxia as an extinction driver for many past and ongoing biologic extinction events.

Original paper published May 21, 2018
Canadian co-author: Andre Desrochers, University of Ottawa –