In a new study, Stanford researchers have strongly bolstered the theory that a lack of oxygen in Earth’s oceans contributed to a devastating die-off approximately 444 million years ago. The new results further indicate that these anoxic (little- to no-oxygen) conditions lasted over 3 million years – significantly longer than similar biodiversity-crushing spells in our planet’s history.
Beyond deepening understandings of ancient mass extinction events, the findings have relevance for today: Global climate change is contributing to declining oxygen levels in the open ocean and coastal waters, a process that likely spells doom for a variety of species.
“Our study has squeezed out a lot of the remaining uncertainty over the extent and intensity of the anoxic conditions during a mass die-off that occurred hundreds of millions of years ago,” said lead author Richard George Stockey, a graduate student in the lab of study co-author Erik Sperling, an assistant professor of geological sciences at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth). “But the findings are not limited to that one biological cataclysm.”
The study, published in Nature Communications April 14, centered on an event known as the Late Ordovician Mass Extinction. It is recognized as one of the “Big Five” great dyings in Earth’s history, with the most famous being the Cretaceous-Paleogene event that wiped out all non-avian dinosaurs some 65 million years ago.
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