The ice cores analyzed in the current study have been shared and scrutinized internationally since they were extracted in the 1990s by Russian scientists. The first hints of life turned up soon after the cores were removed, such as in the series of papers published in Science in 1999.
In their new study, Rogers and his colleagues discovered genetic sequences from cold-loving extremophiles, adapted to the chilly, light-poor environment. Among the bacteria were species that live in hydrothermal vents and organisms that colonize the intestines of rainbow trout, lobsters and tubeworms.
The team also found stretches of RNA and DNA from animals such as tiny, deep-sea-living mollusks and the water flea, a small floating crustacean found in almost every permanent water body on Earth. "The organisms we've been finding are in the very, very small range. These are tiny little creatures," Rogers said.
Finding Vostok's hotspot
Reports of life from Antarctic lakes, especially from the Vostok ice cores, have been plagued by problems with contamination. In the past decade, Rogers and his team developed a painstaking decontamination technique to remove genetic contagion on the outside of the ice core while preserving the ancient DNA and RNA within, he said. The method involves a bleach wash, as well as melting, filtering and refreezing the ice.