Press Release

Thawing Permafrost Microbiomes Drive Climate Change

The Stordalen Mire near Abisko in arctic Sweden was the site of a trio of unique studies that defined the linkages between the specific microorganisms, viruses and the biogeochemistry involved in permafrost carbon degradation.  The studies specifically link changing microbial communities and their activities to greenhouse gas emissions. This understanding will lead to more accurate predictions of the rate of global warming from greenhouse gas emissions produced by thawing permafrost in the next 100 years.

With a team of international colleagues including from Stockholm University, two of the studies were led by Australian Centre for Ecogenomics researchers in the University of Queensland, Australia, School of Chemistry and Molecular Biosciences Dr Ben Woodcroft, PhD student Caitlin Singleton, and Professor Gene Tyson and the third was led by Dr. Joanne Emerson and Professor Matt Sullivan of the Ohio State University in the United States.
“As global temperatures rise, large amounts of carbon sequestered in perennially frozen permafrost are becoming available for microbial degradation,” Dr Woodcroft said.

“To microbes, this is like freezers full of juicy chicken dinners that are thawing out,” said Virginia Rich, an assistant professor of microbiology at Ohio State and study author.

“Until now, accurate prediction of greenhouse gas emissions produced from thawing permafrost has been limited by our understanding of permafrost microbial communities and their carbon metabolisms,” said Dr. Woodcroft.

Using sequencing techniques pioneered by Professor Tyson, over 200 samples from intact, thawing and thawed permafrost sites in northern Sweden were examined.  DNA sequences of more than 1500 microbial genomes all new to science and involved in complex biochemical networks were recovered.

Using viral sequence identification methods pioneered by Professor Sullivan, more than 1900 viral genomes were additionally recovered. Many of them were linked to their likely microbial hosts and biogeochemistry.   

The research also identified entire microbial lineages that were previously unknown and implicated a number of these entirely new lineages in the production of greenhouse gases, while doubling the total known global viral types.

“By recovering the genomes of this number of organisms from these complex soil communities, we have an unprecedented roadmap to be able to understand the roles they play in these communities,” said Professor Sullivan said.

By looking at the genomes of the microbes, the team was able to figure out what capabilities they have.

“It’s like now we have not only their fingerprints but also their resumes, to know both who they are and what they are capable of. The next step is figuring out more about where and when they actively do these things out in the field,” Rich said.

The study is as revealing, and is in the tradition of von Helmont’s experiments in tree growth and Joseph Priestley’s experiments on air and vegetation.  And, at the same time, the analyses presented in these papers is similarly naïve by necessity because we are the very beginning of a new understanding of life’s effects on earth processes.

Ms Singleton said permafrost stores around 50 per cent of the total global soil carbon (or ca. 1580 billion tonnes).
“The Intergovernmental Panel on Climate Change report estimated that between 30 and 99 per cent of near-surface permafrost could disappear by 2100,” she said.  
“Northern permafrost wetlands contribute a significant portion of global methane emissions, particularly as collapsing permafrost can create the perfect anaerobic conditions for methane-producing microorganisms (methanogens), and their metabolic partners, to thrive.
“This is important as methane is a potent greenhouse gas – more than 30 times more efficient at trapping the sun’s radiation in our atmosphere than carbon dioxide.”
She said that as permafrost thaws, methane emissions increase, causing a positive feedback loop where increased atmospheric warming caused more thawing.
The studies are published in Nature, Nature Microbiology and ISMEJ and co-authored by researchers at the University of Queensland, the Ohio State University, Rochester Institute of Technology, the Norwegian University of Life Sciences, Florida State University, Pacific Northwest National Laboratory, University of New Hampshire, University of Arizona and Stockholm University.

Media: Ben Woodcroft, b.woodcroft@uq.edu.au; Caitlin Singleton caitlin.singleton@uqconnect.edu.au, or Professor Gene Tyson g.tyson@uq.edu.au, +617 3365 3829; and Joanne Emerson jbemerson@ucdavis.edu or Professor Matt Sullivan sullivan.948@osu.edu, +1 207 963 2524.

From University of Queensland and Ohio State University press releases revised by Patrick Crill, Stockholm University co-pi and Sweden contact (patrick.crill@geo.su.se).

Links to the articles:
"Host-linked soil viral ecology along a permafrost thaw gradient" in Nature Microbiology https://www.nature.com/articles/s41564-018-0190-y
Blog post about this paper https://naturemicrobiologycommunity.nature.com/channels/346-behind-the-paper/posts/36561-soil-viruses-unlocking-the-secret-garden

"Genome-centric view of carbon processing in thawing permafrost" in Nature https://www.nature.com/articles/s41586-018-0338-1
Blog post  for this paper https://naturemicrobiologycommunity.nature.com/channels/346-behind-the-paper/posts/36570-genomic-centric-view-of-carbon-processing-in-thawing-permafrost

"Methanotrophy across a natural permafrost thaw environment" in The ISME Journal https://www.nature.com/articles/s41396-018-0065-5