Finally, is there a key to combating climate-related permafrost melt?

In the spring, when the sun shines again, algae begins to bloom on the Arctic ice Turning large areas of ice black. When this happens, less sunlight is also reflected, causing the ice to melt. Global warming exacerbates this effect. There is an increase in ice melting.

Snow algae are types of algae that live in snow and ice fields that slowly melt in summer. They occur in glacial ice in mountains or in sea ice in polar regions.

But researchers at Aarhus University in Denmark may now have found a way They can regulate the growth of snow algae and stop the melting of ice in the long term. Laura Perini is a postdoctoral researcher at the Institute of Environmental Sciences Aarhus UniversityAnd her colleagues explain in their latest book Microbiome Publish StadyHow they found giant viruses living next to algae in the Greenland ice sheet.

Perini suspects it Viruses feed on snow algae and naturally control algae blooms“We don't know much about viruses, but I think they could be useful in mitigating ice melt caused by algal blooms.”

Giant viruses versus regular viruses

Natural viruses range in size from 20 to 200 nanometers, while bacteria range in size from 2 to 3 micrometers. However, giant viruses grow to a size of up to 2.5 micrometers, It is larger than most bacteria.

But giant viruses don't just have a larger shell compared to regular viruses. Their genome is also larger. For example, phages (viruses that specialize in bacteria) have between 100,000 and 200,000 codons in their genome. The number of giant viruses is about 2,500,000 viruses.

Although viruses are huge, researchers have them Only based on DNA analysis recognizable. “We discovered the viruses by analyzing all the DNA in the samples. By combing through this huge data set looking for specific genes, we found sequences that had a high similarity to known giant viruses.

Giant viruses were first discovered in the ocean in 1981, where they specialized in infecting green algae in the sea. Later it was Giant viruses are also found in soil and in humans. But this is the first time that giant viruses have been found on the microalgae-dominated surface of ice and snow, Perini explains.

Just a few years ago, this part of the world was considered barren and lifeless. But today we know that many microorganisms live there, including giant viruses.

Scientists analyzed samples of dark ice, red snow and melting holes (cryoconite). They found signatures of giant, active viruses in both dark ice and red snow. According to Perini, this was it It is the first time it has been discovered on surface ice and snow with high levels of pigmented microalgae.

Surrounding the algae is an entire ecosystem: “In addition to bacteria, filamentous fungi and yeasts, there are protists that eat the algae, different types of fungi that parasitize them, and the giant viruses that we found infect them,” Perini explains. . To be able to biologically control algae blooms, One must especially understand the last three groups, namely algae-eating protists, parasitic fungal species, and giant infectious viruses.

Unlike most other viruses, giant viruses have a set of active genes that allow them to repair, replicate, copy, and translate DNA. But why this happens and what exactly they are used for is not yet known, says Laura Perini. Scientists continue to study giant viruses to learn more about their precise role in the ecosystem.

—

source:

Perini, L., Sipes, K., Zervas, A. et al. Giant viral signatures on the Greenland ice sheet. microbiome, 12, 91 (2024). https://doi.org/10.1186/s40168-024-01796-y