Ew, Antarctica is Dirty: Antarctic Lakes Full of Viruses

Alcami and his colleagues analyzed DNA from viruses found in water samples collected fromAntarctica's Lake Limnopolar, a surface lake on Livingston Island. They found nearly 10,000 species, including some small DNA viruses that had never before been identified. In total, the viruses were from 12 different families, some of which may be completely new to science, the researchers suggest.

The results reveal this Antarctic lake supports a virus community that's more diverse than most aquatic environments studied in the world so far — a surprising find considering that the polar region is generally thought to have low biological diversity due to the extreme environmental conditions. The scientists speculate the newly discovered viruses may have adapted specifically to thrive in such harsh conditions.

The team also found the community of viruses changed dramatically depending on the season. When the lake was ice-covered in the spring, the liquid water under the ice was inhabited by mostly small viruses, but in the summer months when the ice melted, the lake was home to mostly larger viruses.

"It looks like a completely different lake in summer," Alcami said. The scientists think the shift might be due to an increase in algae in the summertime, which the larger viruses infect.

The researchers hope to figure out whether any of the viruses are unique to Antarctica. If so, that would shed light on whether microbial life evolved independently in Antarctica, which has been isolated for millions of years, or they were introduced there more recently.