This week scientists have announced the discovery of small creatures frozen deep in a body of water, buried under more than one kilometer of ice in Antarctica. The discovery is actually a result of efforts from the Subglacial Antarctic Lakes Scientific Access (SALSA) project. This project had earlier announced plans to explore the water—which is known as Lake Mercer—using a 60-centimeter drill, hoping to gain more understanding of these mysterious watery environments.
Only a few days after breaking through the ice of Lake Mercer, researchers sent observational instruments under the water to find the perfectly preserved skeletal remains of miniscule animals trapped in ice about half-mile below the surface.
Now, this discovery is not necessarily a surprise: the research team expected to find microbial life forms, as they are common to bodies of water. However, these life forms were not the only discovery the team made. Indeed, the samples collected also contained several carcasses of tiny crustaceans (smaller than a poppy seed) as well as the body of a tardigrade. Tardigrades are eight-legged invertebrates known for their ability to survive in extremely harsh conditions.
As a matter of fact, the discovery of tardigrades was such a surprise that SALSA chief scientist John Priscu said he thought it was a mistake. In fact, he was convinced, at the time, the extracted sediment cores had somehow been contaminated. Accordingly—as all good scientists do—he instructed the team to thoroughly clean the equipment and take additional samples.
Sure enough, the second collection yielded the same results, this time with yet more crustacean shells.
Now, all of this is very important not just because the discovery is novel, but Lake Mercer is the second subglacial lake they have attempted to access. In 2013, researcher drilled about half a mile down into the depths of nearby Lake Whillans but found no evidence of any higher lifeforms; only microbes.
That in mind, Priscu explains that microbial life forms tend to exist in mud under the surface of the ice because this area was an ocean a million years ago. But while that may be true, it still does not explain where the carcasses came from. The scientists theorize, then, that these crustaceans and the tardigrades most likely lived on the surface of the continent and then transported to the lake from the mountains nearby, where similar organisms have been found before. Perhaps moving water or a glacier could have been the mode of transport. Of course, streams and rivers connect several hundred bodies of water under the ice so, if anything, this discovery continues to reveal how little we know about Antarctica.