Updated: Discovery of Positive Methane Feedback from Permafrost Thaw
Update: As pointed out by one of the authors, Rhiannon Mondav, the microbe is not considered an entire new discovery. (See comment below).
Phys.org explains: Scientists from The University of Queensland have discovered a microbe that is set to play a significant role in future global warming.Â UQ’s Australian Centre for Ecogenomics researcher Ben Woodcroft said the methane-producing micro-organism, known as a ‘methanogen’, was thriving in northern Sweden’s thawing permafrost in a thick subsurface layer of soil that has previously remained frozen.
Mr Woodcroft said no one knew of the microbe’s existence or how it worked before the research discovery.Â Fragments of the microbeâ€™s DNA had been found during the last 20 years but no one knew how it worked before the new research discovery.
Mr Woodcroft said global warming trends meant vast areas of permafrost would continue to thaw, allowing theÂ microbesÂ to flourish in organic matter and driveÂ methane gasÂ release, which would further fuelÂ global warming.Â “The micro-organism generates methane by usingÂ carbon dioxideÂ and hydrogen from the bacteria it lives alongside,” Mr Woodcroft said.
Lead researcher and UQ’s Australian Centre for Ecogenomics Deputy Director Associate Professor Gene Tyson said the findings were significant.Â “This micro-organism is responsible for producing a substantial fraction of methane at this site,” he said.Â “Methane is aÂ potent greenhouse gasÂ with about 25 times the warming capacity of carbon dioxide.”
The researchers showed the organism and its close relatives live not just in thawing permafrost but in many other methane-producing habitats worldwide.Â The team made the discovery by using DNA from soil samples and reconstructing a near-complete genome of the microbe, bypassing traditional methods of cultivating microbes in the lab.
The Study:Â Discovery of a novel methanogen prevalent in thawing permafrost
Rhiannon Mondav, et al.Â Nature CommunicationsÂ 5, Article number: 3212Â DOI: 10.1038/ncomms4212
AbstractÂ Thawing permafrost promotes microbial degradation of cryo-sequestered and new carbon leading to the biogenic production of methane, creating a positive feedback to climate change. Here we determine microbial community composition along a permafrost thaw gradient in northern Sweden. Partially thawed sites were frequently dominated by a single archaeal phylotype, Candidatus â€˜Methanoflorens stordalenmirensisâ€™ gen. nov. sp. nov., belonging to the uncultivated lineage â€˜Rice Cluster IIâ€™ (Candidatus â€˜Methanoflorentaceaeâ€™ fam. nov.). Metagenomic sequencing led to the recovery of its near-complete genome, revealing the genes necessary for hydrogenotrophic methanogenesis. These genes are highly expressed and methane carbon isotope data are consistent with hydrogenotrophic production of methane in the partially thawed site. In addition to permafrost wetlands, â€˜Methanoflorentaceaeâ€™ are widespread in high methane-flux habitats suggesting that this lineage is both prevalent and a major contributor to global methane production. In thawing permafrost, Candidatus â€˜M. stordalenmirensisâ€™ appears to be a key mediator of methane-based positive feedback to climate warming.