Ancient 15,000-Year-Old Viruses Appear In Melting Glacier Ice

Century-old moss that has been frozen away in the depths of a Tibetan Glacier has melted to reveal ancient viruses, giving scientists a real glimpse into the organisms that lived tens of thousands of years ago on Earth, as well as the history of their ecosystems.

“The melting has also created some concerns about ancient viruses coming back to haunt us. Melting will not only lead to the loss of those ancient, archived microbes and viruses, but also release them to the environment in the future,” microbiologist Zhi-Ping Zhong wrote in a new study.

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Scientists luckily have access to technology that can keep the ice samples completely sterilized, which makes it easier to work with when it comes to analyzing what exactly is in the ice. Recently, scientists identified dozens of 15,000-year-old viruses from the Guliya ice cap of the Tibetan Plateau.

“These glaciers were formed gradually, and along with dust and gases, many, many viruses were also deposited in that ice. These microbes potentially represent those in the atmosphere at the time of their deposit.”

“These are viruses that would have thrived in extreme environments, with signatures of genes that help them infect cells in cold environments – just surreal genetic signatures for how a virus is able to survive in extreme conditions,” said microbiologist Matthew Sullivan, who also worked on the study.

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When the scientists compared the genetic sequence of the recent discovery they found that a majority of the viruses present in the ice core samples were bacteria that infect Methylobacterium; this classifies the group of bacteria responsible for the methane cycle of ice in a glacier.

These types of bacteria are typically found in plant or soil habitats, which indicates to the researchers that the viruses likely were deposited in the ice through dust particles that lifted from soil tens of thousands of years ago.

“These frozen viruses likely originate from soil or plants and facilitate nutrient acquisition for their hosts.”

“We know very little about viruses and microbes in these extreme environments, and what is actually there,” says Earth scientist Lonnie Thompson.

“How do bacteria and viruses respond to climate change? What happens when we go from an ice age to a warm period like we’re in now?”