Oxygen depletion in ancient oceans caused major mass extinction

https://phys.org/news/2019-08-oxygen-depletion-ancient-oceans-major.html

by Zachary Boehm, Florida State University
Aug. 30, 2019

Late in the prehistoric Silurian Period, around 420 million years ago, a devastating mass extinction event wiped 23 percent of all marine animals from the face of the planet.

For years, scientists struggled to connect a mechanism to this mass extinction, one of the 10 most dramatic ever recorded in Earth's history. Now, researchers from Florida State University have confirmed that this event, referred to by scientists as the Lau/Kozlowskii extinction, was triggered by an all-too-familiar culprit: rapid and widespread depletion of oxygen in the global oceans.

Their study, published today in the journal Geology, resolves a longstanding paleoclimate mystery, and raises urgent concerns about the ruinous fate that could befall our modern oceans if well-established trends of deoxygenation persist and accelerate.

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Their investigations also revealed that the extinction was likely driven in part by the proliferation of sulfidic ocean conditions.

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