As Permafrost Melts, Methane-Munching Soil Bacteria Come to Life

By Veronique Greenwood | November 7, 2011 3:39 pm

There’s a lot going on in Arctic permafrost as it melts and soil bacteria become more active. A new study explores how these bacteria may help or hinder our efforts to control the greenhouse gasses in the atmosphere.

What’s the News: Melting permafrost in a warming world could mean lots of greenhouses gasses, especially methane, released into the atmosphere. But it also means an unusual community of soil bacteria coming out of hibernation, so to speak. A new study looks at what those permafrost microbes do, exactly, as their environment warms up.

How the Heck:

  • The researchers took cores of frozen soil from Alaska and started melting them in the laboratory. As the permafrost melted, they used a technique called metagenome sequencing, harvesting and sequencing DNA from the samples, to identify the permafrost denizens and to see what kinds of proteins they were manufacturing.
  • By performing this step while the samples were frozen and at two points during the melting process, they were able to see how the bacterial makeup of the soil changed over the course of the melt, as some bacteria reproduced like crazy and others did not.
  • They also monitored the amount of methane, carbon dioxide, and other gasses released by the thawing soil and were able to link changes in the gas levels to the activities of the bacteria. Specifically, they found that methane spiked when melting began, but that it quickly dropped, apparently thanks to methane-munching soil bacteria that absorbed the potent greenhouse gas.
  • Don’t celebrate yet, though—those bacteria then excrete carbon dioxide, which, though 25 times less harmful as a greenhouse gas than methane, is still not something we’d like more of in the atmosphere.
  • The researchers also looked to see whether any of the bacteria that had enzymes that could digest nitrous oxide, which is also released by melting permafrost and is an even worse greenhouse gas than methane, grew in numbers as the melting progressed. Unfortunately, they did not.

What’s the Context:

  • Permafrost—soil that’s below the freezing temperature of water for at least two years—exists at both poles and in other cold regions and contains about 1,400 gigatons of trapped carbon in total. That’s more than there is in the atmosphere now. As global warming melts that permafrost, scientists fear that methane, carbon dioxide, and other greenhouse gasses will escape and accelerate massive climate change.
  • How permafrost bacterial life will play into that process isn’t clear, and studies like this will help us get a more complete picture of what the effects of melting will be. The researchers also assembled a rough genome for a methane-eating bacterium in the permafrost, which should provide insight into how the bacterium works.

Reference: Mackelprang, et al. Metagenomic analysis of a permafrost microbial community reveals a rapid response to thaw. Nature (2011) doi:10.1038/nature10576

Image courtesy of Mackelprang, et al and Nature


CATEGORIZED UNDER: Environment, Living World, Top Posts
  • johnq

    “UNLESS you increase the total amount of energy coming in, it will NOT get warmer. It is the energy photon that causes the warming NOT the amount of GHGs.”

    Clearly untrue statement. Measure the daytime air temperature directly above an area of ground. Then build a greenhouse on that ground. Measure the daytime air temperature inside the greenhouse.

    Guess what? The air temperature will be higher. No additional photons, no additional energy.

    Greenhouses increase the air temperature without any additional photons. That’s why gardeners use greenhouses.

    If you keep input energy the same and slow the re-radiation of energy back out, temperature will increase.

    Someone who thinks temperature can’t increase unless the total amount of input energy is increased shouldn’t be calling other people illogical or stupid.

  • mememine69

    The deniers have NOT won the battle for climate change
    belief, the former believers have. So it seems now that only when these
    countless thousands of consensus scientists get off their thrones and start
    acting like they are NOT legally exaggerating, nobody is voting to tax the air
    with corporate CARBON TRADING MARKETS. Exaggerating isn’t a lie, anymore. Face
    it, climate change support is only alive and well in mainscream media and pop culture
    now. Obama didn’t even mention the “crisis” in his state of the union address
    after 25 years of “catastrophic” warnings from “scientists” and what was the
    saintly lab coat consultant’s reaction to being snubbed of their warnings of
    crisis………? You can’t have a little catastrophic climate crisis. So unless
    remaining believers can get the scientists involved in securing support back,
    climate change is doomed for the history books.

    Pollution and the defeat of the smoggy 70’s are real but
    death by CO2 is not. Thankfully, (at least to real planet lovers), it was an academic
    exaggeration fueled by political correctness and unconscionable news editors. And
    we should be happy for that. Not disappointed that a “CO2” crisis wasn’t real.
    If these are not good enough reason s for anyone stop supporting the CO2
    mistake, history will watch you condemn your own children to the greenhouse gas
    chambers with sickening glee.

  • Rick

    Gee, what Republican or green house gas emitting corporation (as though there were a difference) does mememine69 work for? If he needs work, I hear M$FT pays people to post bad things about Apple on the internet.

  • scott

    Mememine, You are absolutley right. Carbon emissions taxes haven’t gained momentum in America for three reasons. 1. We are in a recession, and because of this, people and politicians are lending what little attention spans they have towards economic issues. Putting a Carbon emissions tax on corporations and companies at this point in time would only help to slightly sway companies towards outsourcing. 2. Government corruption, lobbyists, corruption, and some more lobbyists. 3. Not enough people are angry enough to find the means to educate themselves and others on the impact of greenhouse gases on our atmosphere. Until now that is, with the recent growing frustration of the lower/fading middle class towards corporations, people are now swayed towards any possible means of taxing the people who spend $30,000 on a F$$%in handbag.

  • Chrysoprace

    Same response as always to the sockpuppet. Citations please. Oh wait there are none available, presumably due to the giant cover up and conspiracy by scientists who have absolutely no motive to do so. The first credible scientist to find anything to debunk AGW would be swimming in grant money from major corporations. Far more likely that these corporations have in fact funded research in hopes of debunking AGW and had all of them confirm AGW, followed by a quick burial and hard disk format.

  • Dan

    This is a very interesting article. The fact that a bacterial breakdown of methane can occur rapidly in these conditions might have applications within the Canadian beef production process. If the cycle of methane breakdown in cold conditions can be fully understood/replicated, imagine if a system of cold methane capture could be created (infusing it with frozen soil). The cold stored methane could be thawed in a controlled setting with engineered bacteria!

    Mememine69 – I dont even know where to begin, but spelling and grammer are a good start.

  • Barry Johnstone.

    I must stop farting. I must stop farting. I must stop farting. I must stop farting. I must stop farting.

  • adrienne

    Dear Dan,
    Please, please, please respond and say you were joking or being ironic with your closing line.

  • Rooeater

    Time to make everyone (and all their cows!) fart like kangaroos…

  • Matt Horns

    Generally, the people that know the most about climate change are the most concerned, and the people who know the least about climate change are the least concerned.

    Meanwhile, more and more people are finally learning that CO2 emissions’ greatest damage is not climate change, but ocean acidification, which is simple science and absolutely proven to be real.


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