Saturday, April 05, 2014


One of the most intriguing mysteries in geoscience is the mass extinction at the end of the Permian, 252 million years ago. Within the blink of an eye geologically, in 60,000 years or less, 90% of the species on Earth died, and scientists want to know why.
I found this idea very credible and fascinatingly relevant to the situation we are creating for ourselves and our planet now as we race towards the precipice of no return regarding climate change. Suffocating algae blooms in our lakes and oceans, an explosion of the jellyfish population, even the extinction of corals being traced to the reflective micro particles used in sunscreen are all proof that it doesn't take much to to tip the scale. There are many scenarios, but it's the littlest things, the details that are the most deadly.
In the Permian extinction,there has been at least one obvious culprit; at the same time as the extinction, some of the largest outpourings of lava in Earth’s history were occurring in Siberia. Those magmas hit coal beds while passing through the crust, which could have ignited the coal and poisoned the atmosphere, an explanation even recently featured on the TV show #‎Cosmos.
But even with that correlation, the volcanic explanation has never been 100% convincing. First, as I noted recently when a paper nailed down the age of the end-Permian to within 60,000 years; it’s really tough to make a volcano work that fast. Secondly, there were big changes in ocean chemistry which could also contribute to killing life.
A new paper from scientists at MIT blames the extinction in part on the Siberian eruptions, but they allege those volcanoes were but an accomplice to the real killer: a tiny bacterium known as Methanosarcina. A single cell like this one might have killed…everything.
The study just published by a group of scientists led by Dr. Greg Fournier combines several lines of evidence. First, they do detailed measurements of the records of carbon in the atmosphere and conclude that the Siberian eruptions just couldn’t pump out enough carbon to explain the atmospheric changes.
Secondly, they identified the timing of a specific change in the genome of this bacterium; it evolved the ability to take carbon deposited in the oceans and convert it to methane at the end of the Permian.
Combining those features, they proposed that the killer 252 million years ago was this bug going crazy. When it evolved the ability to eat carbon, it went wild, devouring any it could find and releasing an enormous amount of methane. That methane would cause an intense greenhouse effect and convert to carbon dioxide in the atmosphere, poisoning life on land. In the oceans, the methane would react with oxygen, using it up and suffocating many organisms. Others in the oceans would die as the waters turned acidic from the extra carbon dioxide in the atmosphere.
A final piece does relate to Siberia. The scientists also found an excess of nickel in the waters; nickel can be supplied by volcanoes like those in Siberia, and it’s necessary for this microbe to grow. The giant volcanoes in Siberia could have supplied the nickel this bug needed to bloom like crazy, enabling it to poison the world.

It’s an elegant theory for the end-Permian but there are many other elegant theories. Time and additional work will see if this one wins out.

1 comment:

Ol'Buzzard said...

The earth is fragile and once parameters are exceeded all sorts of apocalyptic strands can reach up out of the mire in a rampaged that will completely change the environment.

We always hear talk of the end of the earth; but the earth is not going to end - just our species and ecosystem - the earth will evolve.

the Ol'Buzzard