When it comes to mass extinctions on Earth, the K-T boundary usually grabs the limelight, however, 85 million years earlier, at the Permo-Triassic boundary a much larger mass extinction occurs.

Sephton Discovers Mass Extinction Fungus

When it comes to mass extinctions on Earth, the K-T boundary usually grabs the limelight, however, 85 million years earlier, at the Permo-Triassic boundary a much larger mass extinction occurs, in which up to 96 per cent of all marine species and 70 per cent of land species became extinct.

In a paper published in Geology, Mark Sephton of ESE, reports the discovery of abundant fungi, known as Reduviasporonites, at the Permo-Triassic boundary. The discovery is represents evidence for a catastrophic deforestation at the time of the Earth's largest known mass extinction, which allowed the fungi to proliferate across the planet.

Researchers had previously been unsure as to whether Reduviasporonites were a type of fungus or algae. By analysing the carbon and nitrogen content of the fossilised remains of the microscopic organisms, the scientists identified them as a type of wood-rotting fungus that would have lived inside dead trees.

Fossil records of Reduviasporonites reveal chains of microscopic cells and reflect an organism that lived during the Permian-Triassic period, when the Earth had one giant continent called Pangaea. Geological records show that the Earth experienced a global catastrophe during this period. Basalt lava flows were unleashed on the continent from a location centred on what is present day Siberia. Scientists, however, had thought that land plants, unlike land and marine animals, had weathered the catastrophe without much loss.

The research's findings suggest that much of the vegetation on Pangaea did not survive and that the world's forests were devastated, according to the researchers. Geological records show that there was a massive spike in the population of Reduviasporonites across Pangea as the Permian period came to an end. The scientists suggest that this means that there was increase in the supply of wood for them to decay. The loss of the Earth's forests would have caused a global ecosystem collapse.

Mark Sephton says, "Our study shows that neither plant nor animal life escaped the impact of this global catastrophe. Ironically, the worst imaginable conditions for plant and animal species provided the best possible conditions for the fungi to flourish."

The research team suggest that the basalt lava, which flowed during Permian-Triassic catastrophe, unleashed toxic gases into the air. The gases had a dual effect, producing acid rain and depleting the ozone layer. The outcome was the destruction of forests, providing enough rotting vegetation to nourish Reduviasporonites so that they could proliferate across Pangaea.

Sephton identified the fungi by analysing the carbon and nitrogen content of Reduviasporonites using a High Sensitivity Mass Spectrometer and comparing the results with those from modern fungi. They discovered that Reduviasporonites and modern fungi show similar chemical characteristics.

Related Links

• Geology

Associated Personnel 

• Mark Sephton