After 40,000 Year Slumber, Ice Age-Era Microbes Re-awakened in Alaska

Researchers assured the press that 'there's little to no risk that these microbes could infect anything.'

Published: 10/9/2025, 5:09:14 PM EDT

After 40,000 Year Slumber, Ice Age-Era Microbes Re-awakened in Alaska — Mammoths are one of the oldest creatures in the world. (Screenshot/NTD)

No, it's not a script from a horror movie. Rather, it is a scientific fact that scientists in the Arctic wastes of Alaska, deep in the permafrost, unearthed 40,000-year-old microbes and brought them back to life.

It was a stinky job burrowing deep into the frozen ground, which researchers from the University of Colorado at Boulder did at the Permafrost Tunnel Research Facility. Permafrost, it should be noted, is a mix of soil, ice, and rock. This is the icy graveyard that takes up nearly a quarter of the land in the northern hemisphere. It is where the scientists can better understand our ancient past by finding the remains of animals and plants, as well as bacteria and other microorganisms.

Conducting this research eventually took the Colorado team down a shaft, 350 feet below the surface of the iced earth. As they plunged ever deeper, a foul stench permeated the shaft, as it was clear that remains of mammoths and bison were being revealed, emerging from the frosted walls that had been the tomb for these prehistoric critters.

The findings, published in JGR Biogeosciences, revealed that once permafrost is carefully thawed out, microbes within it will eventually awaken and later form flourishing microbial colonies.

The team, led by Tristan Caro, the lead author of the study and graduate student in geological sciences at CU Boulder, said the stench is "very exciting" because "interesting smells are often microbial."

Tristan Caro, lead author of the study and graduate student in geological sciences at CU Boulder, said in a statement: “To a microbiologist, that’s very exciting because interesting smells are often microbial.”

Once the team gathered the permafrost samples at the Fox, Alaska, site, just 10 miles north of the city of Fairbanks, the many millennia-old samples were brought to the lab and warmed up to as much as 53 degrees Fahrenheit.

The team went on to state that thawing subsurface permafrost leads to a slow "reawakening" of the microbes and added that "(m)icrobial communities that survive and proliferate after burial for thousands of years do not resemble those on the surface and exhibit reduced diversity."

Within six months of a thaw, however, the microbes began to grow and expand rather quickly, with "glistening biofilms" visible without the aid of a microscope.

Caro and his researchers said in their JGR Biogeosciences article that "microbes in subsurface permafrost rely on different kinds of lipids to construct their cell membranes: these compounds may have helped them survive freezing, dark conditions for millennia."

Once awake, Caro assured the press that "there's little to no risk that these microbes could infect anything, although the work does point to some wider perils," including the fact that very ancient microbial life could—due to a potential warming of the planet—return from an icy grave and cause issues, including the release of greenhouse gases—that are not yet understood.