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Mercury behind earth’s last extinction

Toronto, Jan 9 (): Scientists have discovered mercury as one of the major factors behind the earth’s greatest extinction 250 million years ago, when rapid climate change wiped out nearly all marine species and a majority of those on land.

The Earth’s greatest global loss of life, around 250 million years ago, wiped out almost all marine creatures and most land-dwellers. Volcanic eruptions have already been appointed as the main culprit of the Permian-Triassic mass extinction. Previous research indicated that the resulting rise in atmospheric and oceanic carbon led to the great dying. But new findings in the journal Geology point to a large influx of mercury as another cause likely involved in the annihilation.

“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,” says Steve Grasby, adjunct professor at the University of Calgary, Canada and study co-author.

Dr. Steve Grasby says, “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.”

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.

“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,” Dr. Steve Grasby said.

Benoit Beauchamp, professor of geology at Calgary, says 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 period.

“Geologists, including myself should be taking notes and taking another look at the other five big extinction events,” says Beauchamp, also study co-author, according to a university statement.

During the late Permian, the natural buffering system in the ocean became overloaded with mercury contributing to the loss of 95 percent of life in the sea.

“Typically, algae acts like a scavenger and buries the mercury in the sediment, mitigating the effect in the oceans,” says lead-author Hamed Sanei, research scientist at Natural Resources and Grasby’s counterpart at Calgary university.
“But in this case, the load was just so huge that it could not stop the damage.”

The research team warns about the continuing introduction of mercury into the environment through industrial emissions. They plan to take a closer look at mercury levels during other mass extinction events, to see if there is a significant rise in those periods as well and possibly to discover what the effect of rising mercury levels on the Holocene mass extinction might be.