Science

New research suggests microbes may be responsible for the largest extinction in history

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MIT professor of geophysics Daniel Rothman stands next to part of the Xiakou formation in China (Photo: Daniel Rothman)
A photo of the permian triassic boundary at Meishan, China (Photo: Shuzhong Shen)
MIT professor of geophysics Daniel Rothman stands next to part of the Xiakou formation in China (Photo: Daniel Rothman)

A team of researchers from MIT may have found new evidence to shed light on the cause of the most devastating mass extinction in the history of our planet. The event, estimated to have taken place around 252 million years ago, was responsible for the extinction of roughly 90 percent of all life on Earth.

The team's research indicates that the catastrophic event was in fact triggered by the tiniest of organisms, a methane-releasing microbe called Methanosarcina. New evidence suggests that at the time of the extinction, the microbes appeared in massive numbers across the world's oceans, spreading vast clouds of the carbon-heavy gas methane into the atmosphere. This had the effect of altering the planet's climate in a way that made it inhospitable to most other forms of life inhabiting Earth at that time.

It was previously believed that the mass extinction, known as the end-Permian extinction, was due to either vast amounts of volcanic activity, a devastating asteroid strike or prolific all-consuming coal fires. Any of these events could have caused the mass deaths, however there are inconsistencies in the evidence that point away from the traditional theories and towards the new findings presented by the researchers from MIT.

An example of one such inconsistency shows that an extinction event due to extreme volcanic activity would not be possible, as according to research carried out by the MIT team, because such eruptions would not account for the carbon levels present in the rock sediment. Gregory Fournier, a post-doctoral researcher for the project, elaborated on the incompatible nature of the evidence, stating "A rapid initial injection of carbon dioxide from a volcano would be followed by a gradual decrease." This gradual decrease was not present in the sediment. Instead, levels of carbon continued to increase exponentially, thus casting further doubt on the volcanic theory.

A photo of the permian triassic boundary at Meishan, China (Photo: Shuzhong Shen)

Although the team does not believe that the heightened levels of volcanism were responsible for the extinction itself, they do believe that it could have been the catalyst. The sudden and devastating increase in carbon-containing gases present during the end-Permian extinction is put down to a massive bloom of Methanosarcina. However, for this bloom to take place, the microbes would require an abundant source of carbon and nickel, both of which were discovered in a new analysis of sediments in China, and could have been distributed widely through a volcanic eruption.

The case for Methanosarcina being responsible for the extinction is further strengthened by the team's findings that, at the time of the end-Permian extinction, the microbes had undergone a genetic transfer from another microbe. This is what gave the Methanosarcina the ability to produce methane at such a prolific rate.

With the catalyst of volcanic activity, the Methanosarcina were able to spread across our planet's oceans unchecked. This allowed the microbes to produce vast quantities of carbon-containing methane, by harvesting the now carbon- and nickel-rich water. The release of said methane would have had the effect of raising the carbon dioxide levels in the waters, causing ocean acidification, irrevocably altering the ecosystem.

Whilst the team is keen to stress that no evidence can prove definitively what caused the end-Permian extinction, the combination of volcanism and the release of methane from Methanosarcina appears to present the most compelling case.

Source: MIT News

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10 comments
fenshwey
Where did they go? did they exhaust the nickel supply in the water?
ezeflyer
Seems eerily like the melting of permafrost and methane release.
Daniel Gregory
So...the Earth got warmer 252 Million years ago, before the combustion engine, and microbes emitting green-house gas caused things to go extinct. This doesn't fit with previous models of man-made CO2 being the devil, and only cause of all Global Warming, therefore I must reject this scientific data.
Leithauser
Daniel:
Nobody has suggested that man-made CO2 is the only cause of global warming at all times, only that it is the cause of global warming now. In the case of this report, scientists have found the probable source of the greenhouse gases 252,000,000 years ago to be microbes. In the present, they have identified by several means that the source of the greenhouse gases is man. Of course, saying that climate scientists have said something that they never said and then disproving that nonexistent statement is a common tactic of man-made climate change deniers to smear climate scientists.
fidalgoman
DG has certainly got a point. Politics, straw-men, pop-sci and political agenda is the spirit of the age. Even when it comes to science.
doug5380
I think goman has it about right. But from that point I draw the conclusion that science is ill served by it's a$$ociation with politics.
ADVENTUREMUFFIN
Radiolab offers a convincing argument that the 5 km wide meteorite that slammed into earth about the same time threw tons of silicon into the atmosphere (through the vacuum created behind it as it speed through the sky) that rained down, heating the ground to 1000 degrees for a short period and killing anything not underground or under water. www.youtube.com/watch?v=K52vD4WBdLw&feature=youtu.be I wonder if this may have also induced a change in ocean algae?
Noel K Frothingham
DG has certainly got a point. Politics, straw-men, pop-sci and political agenda is the spirit of the age. Even when it comes to science. fidalgoman. ---------------------------- As far as he goes. DGs argument is flawed once one steps back and examines what he is saying. The article points out that there might be a connection between a particular bacteria that is more comfortable underwater but can survive out of water. Not many organisms can survive and flourish in less-than-ideal environments but here's one that could. Why? Simple - abundant food supply. Even bacteria can adapt although it may take a couple of generations to get it right. It can occur. It does occur and when it does, it becomes the new 'king of the mountain' however short its reign might be. This hypothesis is no less plausible than massive CO2 releases from a lake in Africa that killed the population of a small village (100+ people)without warning. One man survived and it was because he was restless, not lying down (CO2 being heavier than air). The people, their livestock as well as the aquatic life known to have flourished in that lake, died by asphyxia with little trace evidence left behind. Some think that denial is river in Egypt whlle others see it as a poor lifestyle choice. Whatever definition one chooses, it is still one of the greatest obstacles the scientific community must overcome - even when presenting a hypothesis.
Marke
Noel K Frothingham 5th April, 2014 @ 08:48 pm PDT
"...Some think that denial is river in Egypt while others see it as a poor lifestyle choice. Whatever definition one chooses, it is still one of the greatest obstacles the scientific community must overcome - even when presenting a hypothesis...."
I differ from you on this issue Noel.
Arbitrarily declaring "the science is in" on the basis of computer modelling with a few years of scanty data collection and labeling anyone who would debate the issue "a denier" because part of the hypothesis is that "it is an unprecedented emergency" is a very large departure from the usual scientific process.
Joseph Boe
The so-called "settled science" of man-made global warming or climate change is anything but...
Politicians write the report that UN IPCC releases - politicians. Many of the scientists who do the research (much of it not intended to draw a conclusion obout man's influence on the climate) have objected to their research being mischaracterized for this reason.
In addition, The Petition Project records over 31,000 scientists ( a great deal more than the number oft touted by the UN as agreeing ) who DISAGREE with the conclusions of the IPCC.
Point? More research needs to be done .