According to a 2021 study using satellite images of glaciers, it was found that almost every glacier on Earth lost ice at a faster rate between 2000 and 2019. There are more than 20,000 glaciers on Earth, and they cover about 10% of the land area. What may be a localized issue for one area of glaciers could multiply exponentially across the globe if ice on other glaciers melts. With that, numerous different microorganisms, including unknown microbes, will be released into the atmosphere.
What have Chinese scientists found in the Tibetan glaciers?
The Chinese Academy of Sciences has undertaken a new study centered around glaciers on the Tibetan Plateau, taking ice samples from 21 glaciers. The Tibetan Plateau is a high-altitude area in Asia between the Himalayas and the Taklamakan Desert.
The researchers found species of microbes that have never been seen before in melting glaciers. Some of these microbes could be harmful to humans. Analysis of the microbes’ genomes showed that some could cause new pandemics. Before the ice dethaws, the team wants to evaluate the potential health risks.
What we know so far
The team sequenced the DNA of the tiny organisms trapped in the ice. They did this to make the Tibetan Glacier Genome and Gene (TG2G) catalog, a vast microbe genomes database. It is the first time that the genes of a group of microorganisms that live in a glacier have been sequenced.
The researchers found 968 microbial species frozen in the ice. Most of them were bacteria, but there were also algae, archaea, and fungi. They wrote about their findings in the journal Nature Biotechnology on June 27.
About 98% of these species were completely new to science. Researchers said this level of microbial diversity was incredible because it is hard to live inside glaciers. Despite harsh environmental conditions like low temperatures, high levels of solar radiation, periodic freeze-thaw cycles, and a lack of nutrients, glaciers’ surfaces are home to a wide range of life.
Thousands of years old microbes can come back to life
Researchers don’t know how old some of these microbes are, but previous research has shown that it is possible to bring back to life microbes that have been frozen for up to 10,000 years.
Scientists have found a surprising number of microorganisms living in Tibetan glaciers before. In January 2020, a team that looked at ice cores from a single glacier found 33 different types of viruses living in the ice, 28 of which had never been seen before.
Researchers say that the surprising variety of microbes in glaciers and the fact that climate change is making glacial ice melt faster make it more likely that potentially dangerous microbes, most likely bacteria, will get out and cause trouble. Suppose pathogenic microbes trapped in ice are released into the environment. In that case, they could cause local epidemics or even pandemics, the authors wrote.
If the scientists’ worse fears are realized, the Tibetan Plateau glaciers could be a source of future pandemics. The Tibetan Plateau glaciers feed fresh water into the Yangtze River, the Yellow River, and the Ganges River. China and India, which have the most people in the world, get their water from these rivers. This danger could happen the world over as ice melts on other glaciers.
How dangerous are these microbes?
According to the evidence, some newly discovered bacteria could be hazardous to humans and other animals. In the TG2G catalog, the team found 27,000 possible virulence factors. These are molecules that help bacteria invade and take over potential hosts. The researchers warned that about 47% of these virulence factors have never been seen before, so there is no way to know how dangerous the bacteria could be.
Mobile genetic elements (MGEs) are large pieces of DNA that bacteria can share with other bacteria. This is something that only bacteria can do. So even if the glacial bacteria die soon after thawing, they can still pass on some of their virulence to other bacteria they meet. The scientists wrote that this genetic interaction between microbes from glaciers and microbes from today “could be hazardous.” Even if these potentially dangerous bacteria don’t last long after they get out of their glaciers, researchers say they can still cause problems.
Benefits of the study
Bioprospecting is the process of looking into natural systems to find valuable new compounds that can be used in medicine, cosmetics, and other helpful technologies. But there is one good thing about this new study, records of microbial communities could be used as “toolkits” for bioprospecting. Keeping such databases is highly significant, particularly if the newly discovered species become extinct in the future, which the researchers said is a real possibility if they cannot adapt to the changes in their frozen home.