Microbes trapped in permafrost for 40,000 years have woken up. They’re alive (and they smell really bad)

A team of scientists has “awakened” life forms that had been frozen in Alaskan permafrost for 40,000 years. They smell like a damp, stuffy basement that has been closed too long, researchers say. They pose no danger to humans, but they were always kept in sealed chambers…

In a new study, a team of geologists and biologists led by the University of Colorado at Boulder (CU Boulder) managed to “resurrect” ancient microorganisms that had been trapped in ice, in some cases, for around 40,000 years.

The study focused on life forms found in , the name given to icy mixture of soil, ice and rock which covers almost 1/4 of the land in the northern hemisphere. It is a kind of frozen cemetery, where the remains of animals and plants, along with numerous bacteria and other microorganisms, have been preserved over time.

The team of researchers discovered that by thawing permafrost, the microbes inside it take some time to become active. But, after a few months, like someone waking up from a long sleep, they begin to form prosperous colonies.

“These samples are far from dead,” he explained. Tristan Caroresearcher in Geological Sciences at CU Boulder and first author of the study, at the university. “Continue perfectly capable of sustaining life robust, decomposing organic matter and releasing it in the form of carbon dioxide.”

Second Sebastian headlead author of , which was featured in an article published in September in the journal JGR Biogeosciencesthis research has profound implications for the health of the Arctic — and the entire planet.

At the moment, permafrost is melting at an alarming rate due to climate change caused by human action.

Scientists fear this trend could trigger a vicious cycle: As permafrost thaws, microbes in the soil begin to decompose the organic matter, releasing it into the atmosphere in the form of carbon dioxide and methane — both strong greenhouse gases.

“It’s one of the biggest unknowns in the climate response“, says Kopf, professor of Geological Sciences at CU Boulder. “How is the thawing of all this frozen ground, where we know there are huge reserves of carbon, going to affect the ecology of these regions and the speed of climate change?”

A long sleep

To explore these unknowns, researchers traveled to a unique location: the United States Army Corps of Engineers. This unusual research facility it stretches more than 100 meters beneath the icy ground of central Alaska.

When Caro entered the tunnel, the width of a mine shaft, he could see bones of ancient bison and mammoths standing out from the walls.

“The first thing you notice when you enter there is the smell. — it’s very intense. It smells like damp, stuffy basement that has been closed for too long“, said Caro, currently a postdoctoral researcher at the California Institute of Technology. “For a microbiologist, this is very excitingbecause interesting smells are often signs of microbial activity.”

In the study, researchers collected permafrost samples aged between a few thousand and tens of thousands of yearsremoved from the tunnel walls.

Right away, added water to the samples and incubated them at temperatures of 4 and 12 °C — cold for humans, but almost “torrid” for the Arctic.

“We wanted simulate what happens during a summer in Alaskaunder future warming conditions in which these temperatures penetrate deeper layers of permafrost”, explained Caro.

A particularity: the water used had heavier hydrogen atomsknown as deuterio. Thus, scientists were able to follow how microbes absorbed that water and used the hydrogen to build the fatty membranes that surround all living cells.

Arctic summers

What scientists observed it was surprising. In the first few months, the colonies grew very slowly — in some cases, replacing just one in every 100,000 cells per day. Under normal laboratory conditions, most bacterial colonies completely renew themselves within a few hours.

But, After six months, everything changed: Some colonies began to produce slimy structures called “biofilms”, visible to the naked eye.

Caro explains that these microbes probably do not pose a danger for humans, although the team has them always kept in sealed chambers.

Colonies didn’t wake up much faster at higher temperatures. This result can help understand what happens in the real world: after a period of heat, may take several months until the microbes become active enough to release large amounts of gases greenhouse effect in the atmosphere.

In other words, the longer Arctic summers become, the greater the risks to the planet.

“There may be a single hot day in an Alaskan summerbut what really What matters is the extension of the seasonwhen these higher temperatures extend into autumn and spring”, concludes Caro.