Here we learn that the massive
extinction of the late Permian caused by the Siberian Traps was driven not just
by the massive influx of CO2, but even more significantly, by a poisoning of
the ocean with mercury compounds. Since huge
amounts of volcaqnic ash would have filled the atmosphere, it seems likely that
the mercury could well have worked its w3ay into all the available living
soils.
Careful geological work could assist
in tracking the effect and discovering just how damaging it actually was on
land in particular. Sea bed disposition
will be cycled over a fair part of the stratigraphy, while land deposition will
sometimes provide traps. Then again,
mercury compounds are heavy and generally migrate downward thanks to erosion.
This item in fact suggests that
the mercury may actually have been decisive.
That opens the question regarding the decisiveness of CO2 toxicity.
Earth's massive extinction: The story gets worse
by Staff Writers
Dr. Hamed Sanei (right), Steve Grasby (center) and Dr. Benoit Beauchamp
(left) discovered another key player assisting in Earth's greatest extinction:
mercury. Dr. Benoit Beauchamp (left) is a professor at the University of Calgary Canada and
adjunct professors at the University
of Calgary University of Calgary
Scientists have uncovered a lot about 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. Now, they have
discovered a new culprit likely involved in the annihilation: an influx of
mercury into the eco-system.
"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," says Dr. Steve Grasby, co-author of a paper published this
month in the journal Geology.
"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." Grasby is a research scientist at Natural Resources Canada and an adjunct professor at the University of Calgary
Dr. Benoit Beauchamp, professor of geology at the University of
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.
"Geologists, including myself should be taking notes and taking
another look at the other five big extinction events," says Beauchamp,
also a co-author.
During the late Permian, the natural buffering system in the ocean
became overloaded with mercury contributing to the loss of 95 per cent 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
Dr. Hamed Sanei, research scientist
at Natural Resources Canada and adjunct professor at the University of Calgary.
"But in this case, the load was just so huge that it could not stop the
damage."
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," adds Beauchamp. Canada North
America , at least, there has been a steady decline through
regulations controlling mercury.
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," says Sanei.
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