Scientists Find 14,400-Year-Old Microbes and Viruses in Tibetan Glacier Ice

Microbiologists at the Ohio State University have found that the ancient bacteria and their phages (bacteria-infecting viruses) from Tibetan glacier ice likely originated with soil or plants, not with animals or humans.

Glacier ice archives information, including microbiology, that helps reveal paleoclimate histories and predict future climate change.

The first reports of glacier-ice microbes appeared early in the 20th century, but were largely ignored until the 1980s when microbes were investigated in the ice core from Lake Vostok — the largest of Antarctica’s almost 400 known subglacial lakes — and subsequent studies near the end of the 1990s.

Those studies revealed microbial cell concentrations of 100 to 10,000 cells in one milliliter in most glacier-ice samples, which are several orders of magnitude lower than other environments such as seawater or soils.

The microbes identified in glacier cores potentially represent the microbes in the atmosphere at the time of their deposition.

“These glaciers were formed gradually, and along with dust and gases, many, many viruses were also deposited in that ice,” said D. Zhi-Ping Zhong, a researcher in the Byrd Polar and Climate Research Center, the Department of Microbiology, and the Center of Microbiome Science at the Ohio State University.

“The glaciers in western China are not well-studied, and our goal is to use this information to reflect past environments. And viruses are a part of those environments.”

D. Zhong and colleagues analyzed ice cores taken in 2015 from the Guliya ice cap in western China.

They determined that the ice was at least 14,400 years old using a combination of traditional and new, novel techniques to date this ice core.

“These are viruses that would have thrived in extreme environments,” said Professor Matthew Sullivan, a researcher in the Byrd Polar and Climate Research Center, the Department of Microbiology, the Center of Microbiome Science, and the Department of Civil, Environmental and Geodetic Engineering at the Ohio State University.

“These viruses have 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.”

“These are not easy signatures to pull out, and the method that we developed to decontaminate the cores and to 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 in Earth’s Atacama Desert.”

“We know very little about viruses and microbes in these extreme environments, and what is actually there,” said Professor Lonnie Thompson, a researcher in the Byrd Polar and Climate Research Center, the Center of Microbiome Science, and the School of Earth Sciences at the Ohio State University.

“The documentation and understanding of that is extremely important: 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?”

A paper on the findings appears in the journal Microbiome.