A new study suggests that ancient viruses in glacial ice hold valuable information about Earth’s climate change.
For decades, the Guliya Glacier, located more than 6,000 meters in the far northwest of the Tibetan Plateau, has been one of the richest archives available to scientists for investigating large-scale paleoclimate changes.
Now, by analyzing ice core samples recovered from the glacier, microbiologists have reconstructed the bits of viral DNA that remained in them and identified nearly 1,700 viral species, about three-quarters of which are newly discovered, he writes EurekAlert.
Drilling in prehistoric ice has no implications for the health of modern humans, as the long-dormant viruses probably infected other dominant microbes rather than animals or humans, but the researchers found that their adaptations significantly influenced their hosts’ ability to survive extremes during variations in Earth’s climate cycles.
“Prior to this work, how viruses related to large-scale changes in Earth’s climate remained largely uninvestigated,” said ZhiPing Zhong, the study’s lead author and a research associate at the Byrd Center for Polar and Climate Research. from Ohio State University.
“Glacial ice is so precious, and we often don’t have the large amounts of material needed to research viruses and microbes.”
Valuable information about Earth’s climate change
As unprecedented warming continues to accelerate the melting of glaciers, the race to collect these ice cores before they disappear for good has only increased their scientific value. For example, the ice sheets examined by the researchers in this paper provided pristine snapshots of virus behavior during three cold-to-warm periods over the past 41,000 years.
The study was published in Nature Geoscience.
Among the different types of new viruses reported, the most distinct viral community observed by the team dates back to about 11,500 years ago, a time when there was a major climate transition from the cold Last Glacial to the warm Holocene.
This suggests that microorganisms were responding to climate change as global temperatures shifted from cold to warm, but it is still too early to say for sure, Zhong said. “This at least points to the potential link between viruses and climate change,” he said.
Using advanced sequencing technologies to examine their genetic signatures more closely, the team’s results also showed that while most of the viruses found in the glacier were unique to Guliya, about a quarter overlapped with known organisms from other areas of the world.
New types of viruses
“This means that some of them were potentially transported from areas such as the Middle East or even the Arctic,” Zhong said.
The researchers argue that if we take the time to better understand how viruses evolved during periods of intense climate, we can gain critical information to predict how modern viruses will react and engage with future warming ecosystems.
“This science is a new tool that can answer basic climate questions that we wouldn’t have been able to answer otherwise,” said Lonnie Thompson, co-author of the study and professor of earth sciences at Ohio State.
Refining these techniques on Earth will likely give scientists new tools to expand the search for life in space environments, aiding efforts to find microbes in the ice fields of Mars or beneath the icy mantles of other planetary bodies, Thompson said.
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Source: www.descopera.ro
