The viruses, recovered from two samples of ice cores taken from the Tibetan Plateau, are new species to science, and they are unlike anything we’ve ever seen. Researchers say it could help us shed new light on viral evolution, but concerns are also looming.
There are diseases in the ice
In a sense, glaciers are time capsules, preserving information from thousands of years ago. This information may relate to past climate, atmospheric chemistry, or even inhabitants of the past.
“These glaciers formed gradually, and along with the dust and gas, many viruses also settled in this ice,” said Zhi-Ping Zhong, lead author of the study and researcher at Ohio State University Byrd Polar and Climate Research. Center that also focuses on microbiology. “Glaciers in western China are not well studied and our goal is to use this information to reflect past environments. And viruses are one of those environments.
Viruses and other microbes can survive for thousands of years frozen in ice. In a new study by researchers at Ohio State University, researchers analyzed ice cores from the Guliya ice cap on the Tibetan Plateau. The carrots, which date back 14,000 years, revealed 33 viruses, 28 of which were completely unknown to science.
Identifying and classifying viruses is more difficult than with other species, and the cataloging process usually takes some time. Yet the viruses would have thrived in cold environments, the researchers believe, based on the genetic analysis.
“These are viruses that would have thrived in extreme environments,” said Matthew Sullivan, study co-author, Ohio State professor of microbiology and director of the Ohio State Center of Microbiome Science. “These viruses have gene signatures that help them infect cells in cold environments – just surreal genetic signatures for how a virus is able to survive in extreme conditions. These aren’t easy signatures to extract, and the method Zhi-Ping developed to decontaminate carrots and study microbes and viruses in ice could help us search for these genetic sequences in other extreme icy environments – Mars, for example, the moon, or closer to home us in the Atacama Desert on Earth.
The researchers were careful to avoid contamination. When studying microbes, it’s always important to make sure that you don’t bring your own microbes into the mix. The researchers therefore first decontaminated the surface of the ice core, then examined the intact parts. This method could also prove useful when looking for microbes on other planets (or satellites).
While this may help us better understand how viruses have evolved and adapted to extreme environments, it is also becoming increasingly important to study viruses and other pathogens frozen in ice.
So far, this is only the third study to identify viruses in glaciers, and it could be useful to conduct more such studies. As temperatures continue to rise due to human-made greenhouse gas emissions, more and more ice will continue to melt, not only from glaciers, but also from ice caps and permafrost. Ice that has remained frozen for thousands of years is about to melt, bringing dormant viruses and bacteria to life.
“We know very little about viruses and microbes in these extreme environments, and what is actually there,” Thompson said. “Documenting and understanding this is extremely important: How do bacteria and viruses react to climate change? What happens when we go from an ice age to a warm period like the one we are experiencing now? “
The study was published in the journal Microbiome.