What would you expect to find in the middle of a frozen Antarctic lake? As if the name Lake Enigma wasn’t puzzling enough, environmental scientists have recently discovered groups of unique bacteria that live their best lives under the ice.
An international team of international researchers has discovered the microbiota—a community of bacteria—that lives beneath the permafrost in Antarctica’s Lake Enigma. Their findings, detailed in a December 3 study published in the journal Communication Earth and Environmentit reveals a previously unknown ecosystem and tells of a lake that once flourished with life before it froze.
Lake Enigma sits between two glaciers, Amorphous and Boulder Clay, in Antarctica’s Northern Foothills. Given the area’s average temperature of 6.8 degrees Fahrenheit (-14 degrees Celsius) and lows of up to -41.26 degrees Fahrenheit (-40.7 degrees Celsius), experts understandably assumed that Lake Enigma was completely frozen.
In the summer of 2019 and 2020, the team—including researchers from the Institute of Polar Sciences, National Research Council of Italy (ISP-CNR)—discovered, surprisingly, that the lake was not completely frozen. Using ground-penetrating radar, they found a layer of water with a depth of 39.4 meters (12 meters) about 11 meters below the surface of the ice.
As a result, the team drilled into the ice to collect samples in a way that prevents water contamination. Back in the lab, the researchers discovered something surprising in the samples: life.
They identified microorganisms, including bacteria that resemble those Pseudomonadota, Actinobacteriotaagain Bacterioidosisand “the presence, and sometimes even dominance, of very small superphylum bacteria Patescibacteria,” the researchers wrote in the study. Superphylum Patescibacteria it is a very simple bacterium with limited functions.
“Together, these features reveal a new complexity in Antarctic lake feeding habitats,” the researchers wrote.
Based on these results, the team suggests that the lake may have once had a thriving and diverse fauna before it was frozen. Although it is not clear when Lake Enigma solidified, the entire continent of Antarctica was covered by ice about 14 million years ago, suggesting that Lake Enigma would have been frozen then as well. Once the ice came in, some bacteria must have survived, which means that the bacteria the researchers identified in their labs may be descendants of this ancient community. However, after growing in isolation for nearly millions of years, they are probably different from their ancestors.
Antarctica is classified as a desert; despite the thick snow, it has very low rainfall. As a result, the researchers also suggested that, since the lake is still fresh, it probably has an unknown source of water—perhaps the nearby Amorphous Glacier. However, Lake Enigma is still “isolated from the outside environment by permanent ice” and contains a “chemically isolated water column,” according to the study. In other words, its classification and stable classification indicate that Potential ice water runoff did not introduce significant external contamination.
Finally, the discovery of microorganisms in such harsh environments sheds light on the current species of Antarctica that cannot be seen with the naked eye, as well as hints of ancient ecosystems that flourished on the frozen continent millions of years ago.
Related topic: Evidence of Life Found in a Deep Lake Under the Antarctic Ice Sheet
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