The "Great Dying" occurred about 252 million years ago and is considered the biggest catastrophe in the history of the planet as 95% of all living organisms were vanished. Terrestrial and marine life suffered critical damage during this era that was before the rise of dinosaurs.
The new study, carried out by researchers from the China University of Geosciences and the University of Cincinnati, suggests that there is substantial evidence proving that volcanic eruptions caused this catastrophic incident.
The massive extinction occurred during a period called Permian-Triassic Boundary when volcanic eruptions released large amounts of mercury vapor into the atmosphere which was transferred into the marine sediment via rainfalls. "Typically, when you have large, explosive volcanic eruptions, a lot of mercury is released into the atmosphere. Mercury is a relatively new indicator for researchers. It has become a hot topic for investigating volcanic influences on major events in Earth's history," Thomas Algeo, a professor of geology in UC's McMicken College of Arts and Sciences, stated.
The volcanic discharges occurred in Siberian Traps, a volcanic systems currently located in the mid part of Russia. The eruptions were intense and lasted for hundreds of thousands of years. "It's not necessarily the intensity but the duration that matters. The longer this went on, the more pressure was placed on the environment," Prof. Algeo stated. More than 3 million km3 of ash were released into the atmosphere during the eruption period. According to Prof. Algeo, the emissions of greenhouses gases raised the average temperature of earth by 10°C.
The temperature rise and the acid raid must have been the most critical causes of the extinction. "We're often left scratching our heads about what exactly was most harmful. Creatures adapted to colder environments would have been out of luck. So my guess is temperature change would be the No. 1 killer. Effects would exacerbated by acidification and other toxins in the environment," Prof. Algeo said.
The "Great Dying" can provide evidence about how global warming influenced the living species back then. Data would be utilized to evaluate our current situation. "The release of carbon into the atmosphere by human beings is similar to the situation in the Late Permian, where abundant carbon was released by the Siberian eruptions," Jun Shen, an associate professor at the China University of Geosciences and lead author of the study, stated.