About 252 million years ago 90 percent of the world's species were mysteriously wiped out; new research suggests the reason behind the mass extinction could be microscopic.
A recent study suggests methane-producing bacteria called Methanosarcina may have all of a sudden bloomed uncontrollably in the oceans, a Massachusetts Institute of Technology (MIT) news release reported.
While volcanoes may not have been the sole cause of the extinction, they still are believed to have played a role. Nickel emitted by the volcanoes could have acted as a nutrient to help the methane-producing microbe's population explode.
Researchers noticed an increase in carbon dioxide in the oceans during the end-Permian extinction. They also found a genetic change in the Methanosarcina that would have allowed it to produce more methane. There was also believed to be an increase in nickel at the time; further supporting the theory.
"A rapid initial injection of carbon dioxide from a volcano would be followed by a gradual decrease," MIT postdoc Gregory Fournier said in the news release. "Instead, we see the opposite: a rapid, continuing increase. That suggests a microbial expansion."
The Methanosarcina are believed to have picked up a faster way to produce methane through gene transfer. The burst of methane would have greatly increased the carbon dioxide levels in the ocean, leading to acidification. Marine organisms with calcified shells are believed to have been largely wiped out during this period, further supporting the idea of acidification.
"A lot of this rests on the carbon isotope analysis," Rothman said. "If it wasn't such an unusual signal, it would be harder to eliminate other possibilities."
"[The work is] a remarkable combination of physics, biochemistry, and geochemistry. It grows out of years of outstanding and patient work that has provided a highly refined time scale for the events that accompanied Earth's most severe cluster of extinctions," John Hayes, a researcher at Woods Hole Oceanographic Institution who was not involved in the research said in the news release.
