Did Methane-spewing microbes wiped out life from earth 252 mn years ago?

Zee Media Bureau

Washington: According to researchers, around 252 million years ago, microbes which are believed to produce methane caused a major disaster may have led to the mass extinction in earth`s history. The microbe namely Methanosarcina, is a member of a kingdom of single-celled organisms. Research shows that the microbe bloomed explosively in the oceans, spewing prodigious amounts of methane into the atmosphere and dramatically changing the climate and the chemistry of the oceans. The carbon deposits show that something caused a significant up-tick in the amount of carbon-containing gases - carbon dioxide or methane - produced at the time of the mass extinction. It turns out that Methanosarcina had acquired a particularly fast means of making methane through gene transfer from another microbe. Given the right conditions, this genetic acquisition set the stage for the microbe to undergo a dramatic growth spurt, rapidly consuming a vast reserve of organic carbon in the ocean sediments, the researchers noted. The resulting outburst of methane produced effects similar to those predicted by current models of global climate change - a sudden, extreme rise in temperatures, combined with acidification of the oceans. In the case of the end-Permian extinction, virtually all shell-forming marine organisms were wiped out - consistent with the observation that such shells cannot form in acidic waters. The new research was published in the journal Proceedings of the National Academy of Sciences. The most famous of Earth`s mass extinctions occurred 65 million years ago when an asteroid impact wiped out the dinosaurs that ruled the land and many marine species. There also were huge die-offs 440 million years ago, 365 million years ago and 200 million years ago. (With Agencies inputs)