Life on Earth has a very long and too complicated history. On more than one occasion, most species went extinct, and the vast biodiversity of the planet had gone back to square one again.
All extinctions severely affected evolution, as the remaining species had to be responsible for forming a new population.
The greatest extinction happened approximately 252 million years ago. It marked the finish of the Permian Epoch at the start of the Triassic Epoch.
Approximately seventy-five percent of all life on land and over ninety percent of ocean life vanished in just a few thousand years.
Intense volcanic activities where Siberia is today and the release of vast amounts of methane from the seafloor were long believed to be the main reasons for the start of the extinction. However, the precise cause of extinction is most controversial for the moment.
Scientists from Italy, Germany, and Canada, in the framework of the EU-funded project BASE-LiNE Earth led by Prof. Dr. Anton Eisenhauer from the GEOMAR Helmholtz Centre for Ocean Research Kiel worked with the Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, managed to accurately reconstruct the entire chain of events from the time using cutting-edge analytical techniques and innovative geochemical models. The study was recently posted in the journal Nature Geoscience.
Analyzing various isotopes of the element boron helped the team of researchers trace the progress of the ocean’s pH values from 252 million years ago.
Increasing quantities of nutrients reached the oceans via rivers, and coasts resulted in over-fertilizations. That culminated in large-scale oxygen depletion and a permanent modification of many elemental cycles: “This domino-like collapse of the inter-connected life-sustaining cycles and processes ultimately led to the observed catastrophic extent of mass extinction at the Permian-Triassic boundary,” said Dr. Jurikova, the first author of the study.
