For the first time, Canadian researchers have suggested that the Earth’s most severe mass extinction was caused by an influx of mercury into the eco-system.
In the study, published in the journal Geology, a team of researchers from the University of Calgary hypothesizes a link between the end-Permian mass extinction and the high levels of mercury released into the environment during catastrophic Siberian Traps volcanic eruptions.
End-Permian Earth (Christine Daniloff)
“No one had ever looked to see if mercury was a potential culprit. This was a time of the greatest volcanic activity in Earth’s history and we know today that the largest source of mercury comes from volcanic eruptions,” said Dr. Steve Grasby, adjunct professor at the University of Calgary and research scientist at Natural Resources Canada.
The researchers found anomalously high levels of mercury in sediments of the High Arctic, Canada, formed during the end of the Permian some 252 million years ago.
“We estimate that the mercury released then could have been up to 30 times greater than today’s volcanic activity, making the event truly catastrophic,” added Dr. Grasby.
Historical variations of mercury deposition before and after the Latest Permian Extinction in a sedimentary section in the High Arctic (Hamed Sanei / Steve Grasby / Benoit Beauchamp)
“This study is significant because it’s the first time mercury has been linked to the cause of the massive extinction that took place during the end of the Permian,” said Dr. Benoit Beauchamp, a co-author on the study. “Geologists, including myself should be taking notes and taking another look at the other five big extinction events.”
“Typically, algae acts like a scavenger and buries the mercury in the sediment, mitigating the effect in the oceans,” explained lead author Dr. Hamed Sanei, adjunct professor at the University of Calgary and research scientist at Natural Resources Canada. “But in this case, the load was just so huge that it could not stop the damage.”
The mercury deposition rates could have been significantly higher in the late Permian when compared with today’s human-caused emissions. In some cases, levels of mercury in the late Permian ocean was similar to what is found near highly contaminated ponds near smelters, where the aquatic system is severely damaged, said researchers.
“The story is one of recovery as well. After the system was overloaded and most of life was destroyed, the oceans were still able to self clean and we were able to move on to the next phase of life,” concluded Dr. Sanei.
Source link: https://www.sci.news/paleontology/article00142.html
