A group of scientists dedicated to the study of glacier ice discovered viruses almost 15,000 years old in two samples taken on a Tibetan plateau in China.
The study published in the magazine Microbiome reveals microbes and viruses unlike any other identified to date and that have survived for years after being frozen. Research results could enable scientists to better understand the evolution of viruses over the centuries.
The team of researchers created a new ultra-clean method of analyzing these types of microorganisms on ice to avoid contaminating the samples.
“These glaciers formed gradually, and along with the dust and gases, many, many viruses also settled on that ice,” explained Zhi-Ping Zhong, one of the study’s authors and a researcher at the Byrd Center for Polar and Climate Research, Ohio State University in the USA.
Experts analyzed ice cores taken from the top of Guliya, at 6,705 meters above sea level, in western China, in 2015. The samples contain ice sheets that accumulate year after year, trapping everything that was in the atmosphere around them at the time each layer froze, creating a kind of timeline, which scientists use to understand more about climate change, microbes, viruses, and gases throughout history.
Using a combination of new and traditional dating techniques, scientists determined the age of the sampled ice core. During the analysis they found genetic codes of 33 viruses, four of which had already been identified previously, however, at least 28 of them are new.
Study co-author Matthew Sullivan, professor of microbiology and director of the Ohio Center for Microbiome Sciences, added that “these viruses have gene characteristics that help them infect cells in cold environments,” which are not easy to extract, for what the method developed by Zhi-Ping to decontaminate the nuclei and study microbes and viruses in the ice could help “look for genetic sequences in other extreme icy environments like Mars or the Moon“.
The researchers’ analysis, based on both the environment and databases of known viruses, showed that viruses likely originated in soil or plants, not in animals or humans.
Lonnie Thompson, one of the main authors of the paper, said that studying viruses in glaciers is relatively new, but it is an area of science that is becoming more important as the climate changes. He also noted the importance of “documenting and understanding” viruses and microbes in these extreme environments, to study and clarify questions about “how do bacteria and viruses respond to climate change?” or “what happens when we go from an ice age to a warm period like the one we are experiencing now?”