We all know that dinosaurs experienced a mass extinction event 66 million years ago, but it got worse. 251,9 million years ago there was an even worse extinction.
Called the "late Permian mass extinction" or "the Great Death", this massive extinction event wiped out about 90% of the marine species of the planet and 75% of the terrestrial species. While scientists have long suspected it was due to volcanic eruptions in what is now Siberia, until now they couldn't explain exactly what the exact cause was.
The study of the great extinction
In a new article published Nature Communications. the "case" is solved. Following extensive eruptions in the area of modern day Siberia, huge clouds of nickel particles turned into aerosols have been dispersed into the air and water. An environmental catastrophe of apocalyptic proportions.
The document, a collaboration between American, Canadian, Chinese and Swiss scientists, points the finger at the huge Noril'sk nickel sulphide deposits in the Tunguska basin. They are the ones who released voluminous volcanic gases rich in nickel into the atmosphere. It was the beginning of the chain of events that led to the massive extinction of life on Earth.
The study is based on the analysis of nickel isotopes in late Permian sedimentary rocks collected in Lake Buchanan at Sverdrup, in the Canadian High Arctic. The remarkable thing about the rock samples is that they had the lightest nickel isotope ratios ever measured. It is this detail that led scientists to conclude that nickel spread in the form of aerosolized particles from a volcano.
The deadly effect of nickel particles
Simple and cruel: when nickel entered the water, it devastated the underwater ecosystem.
The co-author of the study, the professor Laura Wasylenky of Northern Arizona University, ha explained that "nickel is an essential metal for many organisms. An excess of its presence, however, has led to an unusual increase in the productivity of methanogens, microorganisms that produce methane. The increase in methane has been tremendously harmful throughout life dependent on 'oxygen."
An extinction sentence for creatures both in and out of the water. The professor believes the data offers direct evidence linking nickel-rich aerosols, changes in the ocean and the mass extinction that followed.
We now have evidence of a specific killing mechanism
Associate Professor NAU Laura Wasylenky.
What was previously thought about the "Great Death"
Previous studies indicated different effects of volcanic eruptions. Among the hypotheses a general warming of the planet and the acidification of the oceans. Extinction arose from a simultaneous collapse of virtually all life-sustaining processes.
