Scientists Discover Giant Viruses That Could Control Snow Algae Growth, Helping to Mitigate Ice Melt
Every spring, as the sun rises in the Arctic after months of darkness, life returns. Polar bears emerge from their dens, and flocks of Arctic geese return after their long journey south.
Giant Viruses Help Consume Snow Algae, Reducing Ice Melt
Animals are not the only organisms awakened by the spring sunshine. Algae, dormant on the ice, begin to bloom, darkening vast stretches of ice.
As the ice darkens, its ability to reflect sunlight diminishes, causing it to melt faster. Increased melting exacerbates global warming.
Algae dormant on the ice begin to bloom, darkening vast stretches of ice – (Photo: Laura Perini).
Laura Perini, a postdoctoral researcher from the Department of Environmental Science at Aarhus University (Denmark), and her colleagues have discovered giant viruses living on ice alongside algae. Their findings were published in the journal Microbiome.
Perini suspects that the viruses will consume snow algae and may act as a natural control mechanism for algal blooms.
“We do not know much about viruses, but I think they could be useful as a way to mitigate ice melting caused by algal blooms. We are still unsure how specifically they operate and how effective they are, but through further exploration, we hope to answer some of those questions,” she said.
Never Before Found on Ice
Viruses are typically much smaller than bacteria. Common viruses range in size from 20 to 200 nanometers, while typical bacteria measure 2 to 3 micrometers. In other words, viruses are about 1,000 times smaller than bacteria.
However, giant viruses are not like that. They grow up to 2.5 micrometers, and are larger than most bacteria.
Additionally, the gene structure of giant viruses is significantly larger than that of regular viruses. Bacteriophages contain 100,000 to 200,000 letters in their genomes, while giant viruses have about 2,500,000 letters.
Giant viruses were first discovered in 1981 when researchers found them in the ocean. These types of viruses are specialized in spreading green algae in the sea. Later, giant viruses were found in soil on land, and even in humans.
“But this is the first time giant viruses have been found living on the surface of ice and snow, primarily in phytoplankton,” Perini explained.
“We analyzed samples from black ice, red snow, and small depressions in the ice called cryoconite holes. In both black ice and red snow, we found signs of active giant viruses. This is the first time they have been found on the surface of ice and snow containing abundant pigmented phytoplankton,” she said.
The Presence of mRNA
Algae darkening ice in Greenland. (Photo: Laura Perini).
Despite their giant size, these viruses still evade human observation and even detection by conventional microscopes. “Our discovery was made by analyzing DNA from collected samples,” Perini noted, adding that they sifted through large datasets to find signs indicating the presence of giant viruses.
mRNA (messenger RNA) plays a crucial role in protein synthesis within cells. mRNA breaks down quickly unless actively produced by living organisms. The presence of mRNA in the area further confirms the activity of giant viruses on the ice.
Although the potential of these giant viruses to control algae and mitigate ice melt due to global warming is promising, much remains unknown.
“The hosts and their exact mechanisms are still unclear. Some may target protists directly, while others may target algae,” Perini noted. Her research aims to delve deeper into these interactions, with many findings expected to be published by the end of 2024.
