(CNN) Due to Arctic warming, Regional permafrost — A layer of frozen soil beneath the ground — And it can stir up viruses that can endanger animal and human health after tens of thousands of years of dormancy.
A pandemic unleashed by a disease from the distant past sounds like a sci-fi movie plot, but scientists warn the risk is low but underestimated. Radioactive waste can harm wildlife, disrupt ecosystems, and can also be released during thawing.
Kimberly Miner, a climate scientist at NASA’s Jet Propulsion Laboratory, said: “There’s a lot going on with permafrost that’s a concern, and[it’s]very important to keep permafrost as frozen as possible. It really shows why it matters.” at the California Institute of Technology in Pasadena, California.
Permafrost covers one-fifth of the Northern Hemisphere and has supported the Arctic tundra and boreal forests of Alaska, Canada and Russia for thousands of years. It acts as a sort of time capsule, storing ancient viruses, as well as many extinct mummified remains. An animal that scientists have been able to unearth and study in recent years. two cave lions cubs and woolly rhinoceros.
Permafrost is a good storage medium for more than just being cold. An oxygen-free environment where light does not penetrate.But now Arctic temperatures are rising Up to 4x faster than the rest of the planetundermining the top layer of permafrost in the region.
To better understand the risks posed by frozen viruses, Jean-Michel Claverie, Emeritus Professor of Medicine and Genomics at the Aix-Marseille University Medical School in Marseille, France, tested earth samples taken from Siberian permafrost. , checked for the presence of virus particles. The infectiousness contained therein is still there. He was looking for what he described as a “zombie virus” and found several.
virus hunter
Claverie is studying a specific class of viruses that he first discovered in 2003. Viruses, known as giant viruses, are much larger than typical types and can be seen with a regular light microscope rather than a more powerful electron microscope. Types of laboratory work.
His effort to detect viruses frozen in permafrost was announced in 2012. Resurrected wildflowers from 30,000-year-old seed tissue Found in a squirrel burrow. (Since then, scientists have also successfully An ancient microscopic animal brought to life.)
In 2014 he managed to reviving a virus he and his team isolated from the permafrost, By inserting it into cultured cells, it became infectious for the first time in 30,000 years. For safety’s sake, he decided to study viruses that target only single-celled amoebas, not animals or humans.
He repeated the feat in 2015, separate different types of viruses It also targeted amoebas. And in his latest research, Published February 18 in the journal VirusesClaverie and his team isolated several strains of ancient viruses from multiple samples of permafrost taken from seven different locations in Siberia and showed that each of them could infect cultured amoeba cells.
These latest strains represent five new virus families in addition to the two he previously revived. The oldest, based on soil radiocarbon dating, is almost 48,500 years old and comes from an earth sample taken from an underground lake 16 meters (52 feet) below the surface. The youngest sample found in the stomach contents and fur of a wooly mammoth was 27,000 years old.
The fact that the virus that infects the amoeba remains infectious for so long represents a potentially bigger problem, Clavery said. He fears that people will see his research as a scientific curiosity and not recognize the possibility of an ancient virus resurrection as a serious public health threat.
“We view these amoeba-infecting viruses as proxies for all other viruses that may be present in permafrost,” Clavery told CNN.
“We see many other traces of the virus,” he added. “So we know they’re out there. We don’t know if they’re still alive. For no reason, it is capable of infecting its own host.”
Precedents of human infection
Traces of viruses and bacteria that can infect humans have been found preserved in permafrost.
a Lung sample from a woman’s body excavated from permafrost in 1997A village on Alaska’s Seward Peninsula contained genomic material for the influenza strain that caused the 1918 pandemic. In 2012, scientists identified the mummified remains of her 300-year-old woman buried in Siberia. It contained the genetic signature of the virus that causes smallpox.
anthrax in siberia Dozens of humans and over 2,000 reindeer affected The July-August period of 2016 is also associated with deeper permafrost thaw during a very hot summer. Allows old spores of Bacillus anthracis to resurface From old burial grounds and animal corpses.
Birgitta Evengaard, professor emeritus at the Department of Clinical Microbiology, Umea University, Sweden, said there is a need to better monitor the risks posed by potential pathogens in thawing permafrost, but with a cautionary approach. warned against.
“We have to remember that our immune defenses were developed in close contact with the microbiological environment,” said Evengård, part of the CLIINF Nordic Center of Excellence. Animals of the northern regions.
“If there’s a virus lurking in the permafrost that hasn’t been in contact with us for thousands of years, it could be that our immune defenses aren’t strong enough.” is right, the way to fight fear is to have knowledge.”
Possibility of virus spread
Of course, in the real world, scientists wonder how long these viruses can remain infectious after being exposed to current conditions, or how likely they are to encounter a suitable host. I don’t know. Not all viruses are disease-causing agents. Some are benign or even beneficial to the host. Although the Arctic is home to her 3.6 million people, it is still a sparsely populated place, so the risk of human exposure to ancient viruses is very low.
Still, “risks will certainly increase in the context of global warming, where permafrost thaw continues to accelerate and more people live in the Arctic as a result of industrial ventures,” Clavery said. .
And Craberry isn’t the only one to warn that the area could become fertile soil for spillover events once the virus jumps into a new host and begins spreading.
Last year, a team of scientists published researchh is for soil and lake sediment samples taken from Lake Hazen, a Canadian freshwater lake in the Arctic. They sequenced the genetic material in the sediments to identify the virus’s signature and the genomes of potential hosts in the area, plants and animals.
Using computer modeling analyses, we suggested that the risk of virus shedding to new hosts was higher in locations close to where large amounts of glacier meltwater flowed into lakes. This is a scenario that becomes more likely as the climate warms.
unknown result
Miner of NASA’s Jet Propulsion Laboratory said identifying viruses and other hazards in warming permafrost is the first step to understanding what risks they pose to the Arctic. Other challenges include quantifying where, when, how quickly and to what depth the permafrost thaws.
Thaw can be a gradual process of a few centimeters per decade, but it can occur more rapidly, such as in the case of large land slumps where deep and old layers of permafrost can be suddenly exposed. There is also This process also releases methane and carbon dioxide into the atmosphere. This is an overlooked and underestimated driver of climate change.
Miners have cataloged a series of potential hazards currently frozen in the Arctic permafrost in 2021. Paper published in the scientific journal Nature Climate Change.
These potential hazards included buried waste from mining of heavy metals and chemicals, such as the pesticide DDT, which was banned in the early 2000s. Since the experiment began, it has also been dumped in the Arctic by Russia and the United States.
“Sudden thawing rapidly exposes older permafrost layers, releasing compounds and microbes that are sequestered in deeper layers,” Minor and other researchers said in a 2021 paper..
In the research paper, Miner said it was “currently unlikely” that ancient pathogens released from permafrost could directly infect humans.
Minor, however, said she was concerned about what she called “Methuselah microbes” (named after the biblical figure with the longest lifespan). A potential organism to bring dynamics to the current Arctic, with unknown consequences.
The re-emergence of ancient microbes could alter soil composition and plant growth, further accelerating the impacts of climate change, Miner said.
“We really don’t know how these microbes interact with the modern environment,” she said.
According to Miner, the best course of action is to stem the thaw and the broader climate crisis and permanently lock these hazards in permafrost.
