Mercury influx into eco-system may have caused extinction 250m yrs ago

Malaysia Sun (ANI) Friday 6th January, 2012

In a new study, scientists have discovered a new culprit that is likely to have been involved in the Earth's greatest extinction event that took place 250 million years ago when rapid climate change wiped out nearly all marine species and a majority of those on land.

According to the researchers, an influx of mercury into the eco-system may have been responsible for the mass extinction.

"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," Steve Grasby, co-author of a paper from the University of Calgary, said.

"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," he said.

About 250 million years ago, a time long before dinosaurs ruled and when all land formed one big continent, the majority of life in the ocean and on land was wiped out.

The generally accepted idea is that volcanic eruptions burned though coal beds, releasing CO2 and other deadly toxins. Direct proof of this theory was outlined in a paper that was published by these same authors last January in Nature Geoscience.

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, say researchers.

"We are adding to the levels through industrial emissions. This is a warning for us here on Earth today," Benoit Beauchamp from the University of Calgary said.

No matter what happens, this study shows life's tenacity.

"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," Hamed Sanei from the University of Calgary, said.

The study has been published in the journal Geology. (ANI)