Researchers at the University of Southampton have shown that an extinction event 360 million years ago, that killed much of the Earth’s plant and freshwater aquatic life, was caused by a brief breakdown of the ozone layer that shields the Earth from damaging ultraviolet (UV) radiation.
Researchers at the University of Southampton have shown that an extinction event 360 million years ago, that killed much of the Earth’s plant and freshwater aquatic life, was caused by a brief breakdown of the ozone layer that shields the Earth from damaging ultraviolet (UV) radiation. This is a newly discovered extinction mechanism with profound implications for our warming world today.
There have been a number of mass extinction in the geological past. Only one was caused by an asteroid hitting the Earth, which was 66 million years ago when the dinosaurs became extinct. Three of the others, including the end Permian Great Dying, 252 million years ago, were caused by huge continental scale volcanic eruptions that destabilised the Earth’s atmospheres and oceans.
Now, scientists have found evidence showing it was high levels of UV radiation which collapsed forest ecosystems and killed off many species of fish and tetrapods (our four limbed ancestors) at the end of the Devonian geological period, 359 million years ago. This damaging burst of UV radiation occurred as part of one of the Earth’s climate cycles, rather than being caused by a huge volcanic eruption.
The ozone collapse occurred as the climate rapidly warmed following an intense ice age and the researchers suggest that the Earth today could reach comparable temperatures, possibly triggering a similar event. Their findings are published in the journal Science Advances.
Read more at University of Southampton
Image: Prof John Marshall (left), taking samples in Spitsbergen. (Credit: Sarah Wallace-Johnson)
