About 80% of marine and land species went extinct during the end-Permian mass extinction event, which happened 250 million years ago. It was the worst of the five big mass extinction events.

This huge loss of biodiversity was caused by a palaeoclimate emergency that was set off by volcanism on a continental scale that covers most of modern-day Siberia.

As a result of volcanic activity, vast quantities of carbon that had been stored deep inside the Earth’s crust were released into the atmosphere, leading to widespread greenhouse warming.

This global warming event was accompanied by the destruction of the ozone layer. This theory is supported by the high number of malformed spores and pollen grains found, which indicate an increase in damaging UV radiation.

Plants need sunshine for photosynthesis, but they also need to guard against UV-B radiation’s damaging effects on themselves and their pollen in particular.

The Great Dying: Strange Chemical Found In Fossil Plants Confirm Role Of Ozone Depletion In Largest Mass Extinction

Plants achieve this by packing chemicals that act as sunscreen to protect susceptible cells and promote successful reproduction into the outer walls of pollen grains. 

“Without the ‘sunscreen’ compounds, forests could have been sterilized, leading to the collapse of the terrestrial ecosystem,” as explained by Professor Barry Lomax from the University of Nottingham.

According to Prof. LIU, “We have developed a method to detect these phenolic compounds in fossil pollen grains of the Alisporites type recovered from southern Tibet and detected much higher concentrations in those grains that were produced during the end-Permian mass extinction and peak phase of volcanic activity.”

In the most recent Permian deposits, they discovered an increase in UV-B-absorbing compounds (UACs) that was accompanied by an increase in mercury concentration and a decrease in carbon isotopes, indicating a close temporal relationship between massive volcanic eruptions, global perturbations of the carbon and mercury cycles, and ozone layer disruption.

Strange Chemical Found In Fossil Plants Confirm Ozone Depletion As A Factor In The Great Dying

Increased UV-B levels have a significant and enduring effect on the whole Earth system. Increased UV-B stress decreased plant biomass and land carbon storage, which exacerbated global warming, according to recent modeling studies.

Furthermore, increasing phenolic chemical content makes plant tissue less readily digested, making a hostile environment even more difficult for herbivores.

Dr. Wes Fraser from Oxford Brookes University noted that “volcanism on such a cataclysmic scale influences all aspects of the Earth system, from direct chemical changes in the atmosphere, through changes in carbon sequestration rates, to reducing the volume of nutritious food sources available for animals.”

Source: 10.1126/sciadv.abo6102

Image Credit: Getty


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