Lake Vostok, Antarctica's biggest and deepest subsurface lake, might contain thousands of different kinds of tiny organisms — and perhaps bigger fish as well, researchers report.
The lake, buried under more than 2 miles (3.7 kilometers) of Antarctic ice, has been seen as an earthly analog for ice-covered seas on such worlds as Europa and Enceladus. It's thought to have been cut off from the outside world for as long as 15 million years. But the latest results, reported in the open-access journal PLOS ONE, suggest that the lake isn't as sterile or otherworldly as some scientists might have thought.
More than 3,500 different DNA sequences were identified in samples extracted from layers of ice that have built up just above the surface of the lake. About 95 percent of them were associated with types of bacteria, 5 percent of them had the hallmarks of more complex organisms known as eukaryotes, and two of the sequences were linked to a distinct class of one-celled organisms called archaea.
The sequences included close matches for various types of fungi as well as arthropods, springtails, water fleas and a mollusk. What's more, some of the bacteria from the sample are typically found in fish guts — suggesting that the fish they came from may be swimming around in the lake.