Detection of ancient viruses in the melt water of the glaciers of Tibet!

Ancient creatures emerge from a cold reservoir of melting permafrost, almost like a horror movie.

They include incredibly well-preserved extinct megafauna such as the woolly rhinoceros, 40,000-year-old giant wolf remains, and over 750,000-year-old bacteria.

Centuries-old moss was able to come back to life in the warmth of the laboratory. And also, incredibly, there were little worms that were 42,000 years old.

These fascinating images of organisms from Earth’s distant past reveal the history of ancient ecosystems, including details of the environment in which they lived.

But the meltwater has also raised some fears that ancient viruses will return to haunt us.

In a study last year led by first author and Ohio-based microbiologist Shi Bing Zhong, the researchers explained in last year’s study that “thawing will not only result in the loss of these ancient, archived microbes and viruses, but will also result in their release into the environment.” in future”.

Thanks to metagenomics and new methods for keeping ice core samples sterile, researchers can better understand what is in the cold.

Through the study, the team was able to identify a 15,000-year-old archive of dozens of unique viruses from the Gulia ice sheet on the Tibetan Plateau and gain insight into their functions.

“These glaciers formed gradually, and in addition to dust and gases, a lot of viruses were also deposited in this ice,” Zhong said. The team explained in their paper that these microbes are likely microbes in the atmosphere at the time they were deposited.

Previous studies have shown that microbial communities are associated with changes in the concentration of dust and ions in the atmosphere, and may also indicate the climatic and environmental conditions of the time.

Among these frozen records of antiquity at 6.7 km (22,000 feet) above sea level in China, researchers found that 28 of the 33 viruses they identified had never been encountered before.

“These are viruses that could thrive in extreme conditions,” said Ohio State University microbiologist Matthew Sullivan, “the fingerprints of the genes that help them infect cells in cold conditions are just genetic signatures of how a virus manages to survive in extreme conditions.” . .

By comparing their genetic sequence to a database of known viruses, the team found that the most common viruses in all ice core samples were phages that infect Mythylobacterium, a bacterium important to the methane cycle in ice.

They were more closely related to viruses found in strains of Mythylobacterium in plant and soil habitats, consistent with a previous report that the main source of dust deposited on the Gulia ice cap likely comes from the soil.

“These frozen viruses most likely come from soil or plants and make it easier for their hosts to obtain nutrients,” the team concluded.

While the specter of ancient viruses seems particularly troubling in the wake of the Covid-19 pandemic, the biggest danger is that melting ice is being released — vast stores of trapped methane and carbon.

But it is clear that ice can also contain information about past environmental changes, as well as the evolution of viruses.

Earth researcher Loni Thompson, who noted that we still have many important unanswered questions, explained: “We know very little about viruses and microbes in these harsh conditions and what is really out there. How are bacteria and viruses responding to climate change? What’s happening? when will we move from the ice age to the warm period, like now?

This study was published in Microbiome.

Source: Science Alert.