British paleontologists may have successfully explained a mass extinction that occurred 359 million years ago. They believe that this event, known as the “Devonian extinction”, was due to a temporary reduction in the ozone layer.
Specialists want evidence of fossils dating from this time found in eastern Greenland and the Bolivian Andes, they explain in a study published Wednesday in Science Advances . These vestiges of spores of terrestrial plants indeed present a malformation.
A high degree of UV radiation
According to the authors of the study, "the extinction coincided with a high degree of UV-B radiation proving a reduction in the ozone layer". Researchers also write that Earth experienced a period of global warming during this era. The work also evokes levels of mercury testifying that a volcanic eruption could not have been at the origin of the mass extinction.
The latter affected terrestrial species and those evolving in shallow waters. Shellfish, at the top of the food chain in this latter environment, then disappeared. Sharks and bony fish then became the dominant animals. The phenomenon has also led to the extinction of most of the freshwater fauna and terrestrial plants.
Directions for the future
Scientists also believe that their findings may provide clues to the future climate situation.
"Recent estimates suggest that we will reach global temperatures similar to those observed 360 million years ago with the possibility that a similar reduction in the ozone layer will occur again," explains Phys.org John Marshall, lead author of the study. According to him, "we would then go from a state of climate change to a state of climate emergency".
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