Treasures and dangers of permafrost

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Treasures and dangers of permafrost
Treasures and dangers of permafrost

Viruses that have dormant in frozen soils for millennia may reappear on the surface as a result of global warming. Drilling ice in the High North risks awakening microbes buried millions of years ago. They will be in direct contact with people who are at great risk to their health.

Permafrost occupies a fifth of the earth's surface and covers high latitudes with its icy hands. But the fragile giant is capable, if it melts, at worst (greenhouse gas emissions, viruses hidden deep for millennia, splashing fresh water into the oceans), and at best (discovering archaeological treasures). A journey to the very heart of the permafrost.

The Vector Institute was used during the Soviet era to develop biological weapons. For a long time it remained classified, now it is one of two places on the planet where the smallpox virus is stored. And it was in this highly secure facility that research on prehistoric viruses began a few months ago. Russian scientists are studying almost 6,500-year-old horse tissue found in Siberian permafrost in 2009. Skeletons of mammoths, moose, rodents … Scientists of this institute, as explained by the Siberian Times, strive to continue sequencing the entire genome in order to "obtain information about the biodiversity of microorganisms present in the samples." And thus learn more about "zombie viruses".

In the face of global warming, the resurgence of viruses or bacteria that have so far been buried in permafrost is an increasing concern, which the current pandemic is only exacerbating. Thus, several scientists expressed their concern last year in an open letter to the World Health Organization warning that permafrost "is Pandora's veritable chemical and biological box." Its melting can be a real disaster for humanity.

In Siberia, the oldest and deepest layers can be 1.5 million years old, and they can contain an unimaginable number of microbes that have been sleeping in animal corpses for hundreds or even thousands of years, waiting for their awakening. And this is no longer a fantasy: five years ago, a rise in temperature led to the awakening of anthrax, which disappeared more than seventy years ago in Siberia. Anthrax killed entire herds of deer and infected several people, resulting in the death of a child.

As Régis DeBruin, a paleogeneticist at the National Museum of Natural History, explains, “Anthrax is a bacterium that can reduce its metabolic activity. Thus, it can survive for years in permafrost. A priori, these abilities are inherent not only to viruses, which are not cellular organisms, but to simple RNA or DNA molecules enclosed in a protein envelope. But we know little about their ability to survive in these conditions. " The scientist further notes that it has not been established whether the anthrax was stored for only a few years or much longer. “It's not the same,” he notes.

Risk to humanity

About ten years ago, virologist Jean-Michel Claverie and his team succeeded in reactivating very specific Siberian viruses that are at least 30,000 years old. “These giant viruses - about the size of cells - infect amoebas, single-celled organisms,” he explained.- Consequently, they are not dangerous to humans: amoeba underwent changes 1 billion years ago, so it is unlikely that viruses are capable of infecting both amoebas and humans. But our discovery proves that viruses can sleep tens of thousands of years in the ground before waking up.”

Could more "classic" viruses infecting humans or animals have the same abilities? Nobody knows, but there is no evidence that this is not the case. Professor Claveri reminds that this kind of research is rather confidential, because the lands of Siberia are difficult to access, on the one hand, due to a particularly difficult climate, on the other hand, because Russia often considers these territories to be strategic and does not really like to see how “Rob” her treasures. First of all, the scientist believes that no one will be allowed to search for permafrost and try to reactivate microbes that pose a potential risk to humanity. But what is happening at the Vector Institute? How is research done there? After the press release published in February, there is no information.

However, for scientists, the biggest threat remains a virus, the existence of which we do not yet suspect, which we are not looking for, but which may reappear in places hitherto inaccessible. “Global warming opens up the sea lanes of the High North, allowing the Russians to use industrial equipment and entire brigades to explore for minerals in hitherto inaccessible areas,” says Jean-Michel Claverie. “They drill holes more than a kilometer deep, risking awakening microbes buried millions of years ago. They will find themselves in direct contact with people without any health precautions. And this is a real danger."

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