14 DAY TRIAL // Up until now, it has been thought that the mass extinction of the species which populated the Earth at the end of the Permian period (250 million years ago) was caused by a meteorite or the deep-sea methane release.
But a new study carried out by a team of researchers at the Imperial College London comes with a solution to the mystery of the extinction which obliterated more than two-thirds of reptile and amphibian families.
The analysis of a unique set of molecules found in rocks taken from the Dolomites in Italy has enabled scientists to build up a picture of what actually happened. The molecules are the remains of polysaccharides, large sugar-based structures common in plants and soil, and they tell the story of the extinction.
The molecules date from the same time as a major volcanic eruption that caused the greatest ever outpouring of basalt lava over vast swathes of land in present day Siberia.
The researchers believe that the volcanic gases from the eruption, which would have depleted earth's protective ozone layer and acidified the land and sea, killed rooted vegetation. This meant that soil was no longer retained and it washed into the surrounding oceans.
The chemistry of the rocks reveals that although the sugar molecules were found in marine sediments, they derived from land, supporting the theory that massive soil erosion caused them to end up in the sea.
Soil materials in the oceans would have blocked out light and soaked up oxygen. Analysis of rock chemistry suggests that after the soil crisis on land, the marine ecosystem succumbed to the stresses of environmental change and oceanic life faltered, completing a global catastrophe.
Dr Mark Sephton, author of the study, believes that humanity has to learn from this catastrophe in order to avoid the repetition of history.
"Land degradation is a worsening global problem thanks to human activity and soil erosion has caused the loss of a third of arable land over the last forty years. 35% of the Earth's land is now soil-free. Identifying the nature of the end Permian soil crisis may help us understand what is in store for us in the years ahead," he said.