Antarctica's Lake Enigma, located beneath the ice in Victoria Land, has revealed a hidden ecosystem. Previously thought to be completely frozen, the lake contains a layer of fresh water populated by diverse microorganisms.
Researchers conducted an expedition from November 2019 to January 2020, employing ground-penetrating radar to uncover at least 40 feet (12 meters) of liquid water beneath the ice. Following this, they drilled into the ice and deployed a camera to explore the lake's depths.
To understand the origin of the water, the team analyzed its chemical composition. Given the area's low precipitation and high evaporation rates, they concluded that the lake's water is replenished by the nearby Amorphous Glacier through an unknown underground pathway.
Despite being isolated from the atmosphere, Lake Enigma hosts various kinds of microbial life. The bottom of the lake is covered in microbial mats, with some organisms being photosynthetic, resulting in a high concentration of dissolved oxygen.
The researchers observed that these mats formed unique structures, including thin, spiky coatings and large amorphous formations resembling tree-like structures, reaching heights of up to 40 cm (16 inches) and diameters of 50 to 60 cm (20 to 24 inches).
Among the microbial residents were several species of Patescibacteria, which typically do not thrive in high-oxygen conditions. Their presence suggests they may have developed unique metabolic adaptations to survive in this extreme environment.
This discovery underscores the complexity of food webs in permanently ice-covered lakes, revealing symbiotic and predatory relationships previously unrecognized. Environments similar to Lake Enigma may exist on icy moons such as Europa or Enceladus, potentially offering insights into extraterrestrial microbial life.