Thawing Arctic permafrost and the threat of time-traveling pathogens

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As the climate warms, scientists argue that “time-traveling pathogens” released by thawing Arctic permafrost could pose a threat to modern ecosystems.

permafrost This is a solid layer of frozen soil made of soil, sand, and rock inside Plateau or height Such as Greenland, Alaska, Siberia, the Tibetan Plateau and northern Canada. New research finds that these permafrost trap microbes that remain dormant for long periods of time, but a warmer planet could create the right conditions for these pathogens to return from the past.

To better understand potential environmental influences, an international team of researchers numerically modeled the interactions between ancient viruses and modern bacteria in a study published July 27 in the journal Nature. PLOS Computational Biology.

Through tens of thousands of iterations, the research team tracked how viruses affect species diversity in bacterial communities. About 1% of ancient viruses cause major disruption to the digital ecosystem. Pathogens increase diversity by up to 12% or, conversely, reduce species diversity by up to 32%. Virus invaders don’t just survive, they evolve over time, throwing the system off balance.

The researchers used software called Avida to simulate whether pathogens have made it through the ecosystem. In a two-dimensional network, bacterial organisms interact with their environment to compete for energy and space. Competitors who have found their niche can multiply and survive through tournaments.

Thus, there is less error in reproduction which creates genetic diversity, Which causes more complications environmental system. When a virus enters this environment, like other parasites, it can only gain energy by filtering out suitable bacterial hosts. The hosts are then unable to receive the energy they need to survive or reproduce, and then die.

Does this mean that almost a third of humans and other organisms are at immediate risk of dying from an awakened viral disease? No. But lead author Giovanni Strona and co-author Cory Bradshaw said the findings added another layer of concern to the risks of a warming climate.

In the last two decades, more research has been devoted to understanding its consequences thaw permafrost In polar regions, such as A January 2022 NASA study who investigated the effects of carbon release during sudden thaw events and Jean-Michel Clavery’s decade-long observations of infectious pathogens trapped in permafrost.

Claverie, professor emeritus of medicine and genomics at the University of Aix-Marseille School of Medicine, revived what he calls “zombie” viruses from the permafrost in 2014 and 2015, and he and his team have reported five new families of ancient viruses capable of infecting amoebas in a study In February, as previously reported by CNN. Clavery’s research has shown that ancient microbes could remain infectious even if they were dormant for tens of thousands of years.

Using assumptions from Claverie’s research, Bradshaw, director of the Global Environment Laboratory at Flinders University in Australia, and Strona, senior researcher at the European Commission’s Center for Joint Research, designed a simulation to determine the consequences this pathogen could have.

And while the 1% of pathogens that cause major disturbances seems low, 4 sextillion cells escape the permafrost every year, says Bradshaw. It’s over The number of stars in the galaxy.

“One percent in 4 sextillion is a number most people can’t even imagine. There are many, many possibilities for that to happen. The odds are rare for one virus, but there are many possible viruses,” he told CNN in a telephone interview.

Bradshaw likens permafrost viruses to other invasive species. In the real world, most invasions fail, which the research reflects. He said the reason we still have problems with invasive species is because there are so many introductions to ecosystems.

Read more: Invasive species worldwide in pictures

Strona said that during the study’s successful invasion event, a 32% loss in species diversity does not mean that the virus killed a third of all bacteria in the digital ecosystem. Instead, it meant that the entire ecosystem experienced a 32% loss in bacterial diversity.

When viruses infect bacteria and kill their hosts, the effect on ecosystems is catastrophic. Resources that once existed in balance are no longer available, Bradshaw said, so the remaining species are forced into a race for survival. Predator and prey They fight for the use of resources remaining, resulting in an unbalanced system. When there are fewer predators eating their prey, it reproduces, populates, and then consumes more resources. Then overproduction reduces the number of prey in the process of natural extermination. If there were more predators, they would eat too much prey to survive sustainably, leading to the same result.

The researchers found that the introduction of the virus was the only cause of the large fluctuations in species diversity.

Modern organisms, including humans, have few, if any, natural defense mechanisms against ancient pathogens. For the research team, say Strona and Bradshaw, this research is more of a call to action than a real warning.

“We don’t need to sound the alarm now,” said Dr. Kimberly Miner, climate scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. He believes there are more pressing concerns about the climate crisis that could be more contained, such as slowing the release of carbon into the atmosphere.

This study is a great first step in identifying risks from these unknown variants, said Miner, who was not involved in the study. But the possibility of infection from this emerging pathogen remains “highly unlikely”.

The areas containing Earth’s permafrost are sparsely populated. If the ancient pathogen somehow managed to escape, they would have a hard time finding people to infect. Additionally, permafrost thaws gradually throughout the year at a rate of about 1.2 inches (3 centimeters) per season, and most of the 4-sextillion cells are released during this gradual thaw, Miner said.

He explained that the sudden thawing of permafrost in the Arctic, which sometimes occurs as quickly as possible over a period of days, is “our biggest concern in terms of the release of organisms that we don’t know about.”

As global average temperatures increase, these sudden meltdowns will become more common. After record high temperatures in July, drone footage captured Siberia’s largest icy crater sinking as snow melts underground.

Strona and Bradshaw point out that more research is needed to expand the implications of their findings in humans or animals. The researchers say their intention is to provide a framework for assessing the risk of ancient biological invaders.

In all of these cases, say the study authors, the only countermeasure – whether it be sea level rise, deadly heat or the emergence of pathogens – is to slow or stop the carbon emissions that drive global warming and protect Arctic ecosystems. Without doing so, they say, environmental streams would not become science fiction.

2023-08-18 21:54:13
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