The discovery of more than 900 species of microbes in the glaciers of the Tibetan Plateau is hardly surprising. And we are talking about an area of the planet where temperatures are freezing, high levels of radiation are recorded and for a microbe there is little food, it itself freezes and later thaws, depending on the season of the year in which it occurs. halle The finding is the result of the first genomic catalog dedicated to the glacier ecosystem.
“The surface of glaciers harbors a wide variety of life, such as bacteria, algae, archaea, fungi, and other microeukaryotes. Microorganisms have demonstrated their ability to adapt to these extreme conditions and contribute to vital ecological processes,” the team write in their new article that has been published in Nature Biotechnology .
“Glacial ice can also act as a record of microorganisms from the past, with ancient aerial microorganisms (over 10,000 years old) having been successfully revived. Thus, the glacial microbiome also provides an invaluable chronology of the microbial life on our planet,” the post reads.
Researchers have set their sights on the glaciers of the Tibetan Plateau, a 2.5 million square kilometer, high-altitude region that lies between the Himalayas to the south and the Taklamakan desert to the north. The area is a source of water for surrounding areas of Asia and climate change has hit it hard, as more than 80% of its glaciers have begun to retreat .
Knowing what microbes are in the area is important in case they could be problematic for humans if they thaw. Also in case they disappear, to have a record of their existence.
To carry out their task, the researchers took samples of snow, ice and dust from 21 Tibetan glaciers over four years , between 2016 and 2020. They also grew some of the microbes in a laboratory to learn more about them and recover a greater proportion of your genome.
What most excited scientists is that 82% of the genomes were new species . 11% of the species were found in a single glacier, while 10% were found in almost all the glaciers studied.
The project has become what the researchers call the “Tibetan Glacier Gene and Genome Catalog” (TG2G), and it is expected to serve researchers well into the future, with further additions as more species are found.
Could these microbes cause pandemics?
The high microbial diversity that exists within glaciers, coupled with increased melting due to climate change , increases the chances that potentially dangerous microbes, likely bacteria, will escape and wreak havoc, the researchers say. Pathogenic microbes trapped in ice could lead to local epidemics and even pandemics if released into the environment, the authors wrote.
Evidence from the study suggests that some of the newly discovered bacteria could be very dangerous to humans and other organisms. The team identified 27,000 potential virulence factors, i.e. molecules that help bacteria invade and colonize potential hosts, within the TG2G catalogue. The researchers cautioned that around 47% of these virulence factors had never been seen before, so it is unknown how harmful they might be.
Even if these potentially dangerous bacteria don’t survive long after glaciers have thawed, they can still cause problems, the researchers said. Bacteria have the unique ability to exchange large sections of their DNA, known as mobile genetic elements (MGEs), with other bacteria. Thus, although the glacier bacteria die shortly after being thawed, they can transmit part of their virulence to other bacteria that they find along the way. This genetic interaction between glacial microbes and modern microorganisms “could be especially dangerous,” the scientists wrote.
The glaciers studied could be a hot spot for causing pandemics, as their fresh water reaches several rivers such as the Yangtze River, the Yellow River and the Ganges River, which supply two of the most populous countries in the world: China and India. We already know from COVID-19 that pandemics spread faster in areas that are highly populated.
This potential risk would not only affect Asia . There are more than 20,000 glaciers on Earth, covering about 10% of the land mass, and they probably harbor their own communities of microbes.
In April 2021, a study using satellite images of glaciers found that nearly all of Earth’s glaciers had rapidly lost ice between 2000 and 2019, raising the risk that pandemic-spawning microbes could escape into any part of the planet. The researchers cautioned that “potential health risks [of these microbes]” need to be assessed before they can be released.
Referencia: Liu, Y., Ji, M., Yu, T. et al. 2022. A genome and gene catalog of glacier microbiomes. Nat Biotechnol. DOI: https://doi.org/10.1038/s41587-022-01367-2
