Ancient bacteria reanimate across the Arctic as permafrost melts

Ancient DNA in Alaska forgoes reconstructed T-rex and wooly mammoths, yet still manages to be more fantastic than the most outlandish sci-fi films. Millennia-old creatures reawaken themselves here, no Jurassic Park assembly required, thanks to the cryogenic chill of now-melting permafrost.

In 2005, NASA’s Richard Hoover walked deeper and deeper into a permanently frozen hillside, collecting samples with gloved hands, Ned Rozell wrote in an Alaska Science Forum article. These soil samples from the Fox Permafrost Tunnel held all manner of ancient bacteria. The soil had been there more than 30,000 years.

When the soil thawed, the 32,000-year-old bacteria woke up right away and got back to work. Their DNA building blocks stayed intact over the millenia to such a degree that they could still go about their lives as they once did. They used to live at the bottom of an pond before the hill formed.

Hoover and his colleagues found a bacteria new to science, so different from anything that could have come in on the tunnel’s other visitors that they ruled out contamination.

Fox Permafrost Tunnel. March 17, 2007. Photo by Travis S., baggis on Flickr.

This posed a problem for the boreal forest. If the bacteria could spring back to life in the lab, then they could wake up where permafrost melts. They’re decomposers, meaning they break down bits of organic matter in the newly-melted soil back to its gaseous building blocks — often greenhouse gases like carbon dioxide and methane.

The University of Alaska Fairbanks’s Vladimir Romanovsky worked on a team in 2005 to find out what exactly reanimated Arctic bacteria did day-to-day. Some made carbon dioxide, some made methane. The former substance floats around in the atmosphere longer, but the latter is a more powerful greenhouse gas.

Even if this melted soil becomes more hospitable for plants, shrubs would only soak up the new carbon dioxide for about 15 years before too much is released for them to keep up, according to a 2009 Nature article. The boreal forest and Arctic are a sink of carbon dioxide only for a decade or so, before they become a source.

California scientists returned to Alaska to see how these bacteria behave and interact once they’ve thawed. Their findings appeared online in Nature Nov. 6, and New Scientist wrote about the findings. Essentially, the team tracked the population as it woke up and settled back into a bustling, decomposing and greenhouse gas-producing community.

32,000-year-old bacteria. Living bacteria shown in green. Image courtesy NASA.

If 32,000 years seems incomprehensible, try 100 million years. British scientists found a microbe on the Arctic seafloor that loves heat. The bacteria gets pushed up from their beloved petroleum reservoirs by currents, and have to wait to be buried again. That could take tens of millions of years. Like plants that wait until a fire to release their seeds, these bacteria bank on the right conditions waking them from slumber.

It’s difficult to imagine how colonies can survive for so long.

The permafrost tunnel bacteria weren’t in a typical dormant form, according to the New York Times. DNA would break down too quickly if they were, anyway. Instead, maybe they keep going just enough to repair themselves and wait for the light of day.

A little challenge: If you have the opportunity, go to the Permafrost Tunnel. In addition to knowing you’re surrounded by 30,000-year-old sleeping bacteria, you can more tangibly see still-green leaves from the same time period. You can also sort through dozens of panoramas in a virtual tour at 360Cities.

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