Lake Enigma in Antarctica, covered in permanent ice, is home to life forms that challenge scientists’ expectations.
For a long time, researchers thought that this lake was completely frozen. However, after several years of study, they discovered that beneath the icy layer a thriving ecosystem. An international team has been able to prove that the water under the ice is actually liquid, at a depth of up to 12 meters.
Coordinates projected in UTM58S (WGS84).
Lake Enigma is located between two glaciers, in an extreme environment where average temperatures are -14°C (with a minimum of -40.7°C). The use of ground-penetrating radar revealed that a body of water persisted beneath the surface frozen. This discovery challenges our understanding of the conditions necessary for life in such extreme environments. Drilling carried out in 2019 and 2020 made it possible to extract water samples, which revealed the presence of microorganisms. These bacteria belong to poorly studied families such as Actinomycetota and the Pseudomonadota. The researchers even found extremely small bacteria, Patescibacteriawhich constitute a group of simple microorganisms known for their activity and their genome reduced, as well as for the smallness of their cells.
The discovery of such an ecosystem in a lake frozen for millions of years raises many questions. Scientists suggest that this lake was once home to abundant life before ice covered it. Today, only a few microorganisms have survived this change, giving rise to the life forms seen today.
Lake Enigma is particularly interesting because, unlike other Antarctic lakes, it appears to have a hidden water source which could explain its persistence. Some researchers believe that the glacier Amorphous might be responsible for the water supply, but this theory remains to be confirmed.
B. Additional view at drilling point DP#2 (depth 9.3 m).
C. Underwater survey at drilling point DP#4 (depth 22.5 m).
D. Additional view at drilling point DP#4 (depth 22.5 m).
E. Underwater survey at drilling point DP#C22 (sampling depth 22.0 m).
F. Additional view at drilling point DP#C22 (sampling depth 22.0 m).
G. Influx of supraglacial meltwater from the Amorphous Glacier to the surface of Lake Enigma observed on January 3, 2020.
H. Visual evidence of the influx of supraglacial meltwater during the XXXV Italian Antarctic Expedition.
The study also revealed stable water chemistry, raising questions about how water remains intact despite its isolation. Researchers continue to explore this region to better understand how such an ecosystem can persist in such a hostile environment.
Lake Enigma could well be a valuable clue to the evolution of life on Earth, and perhaps even on other planets where extreme conditions persist. By studying this small subglacial world, scientists hope to better understand the limits of life and its capacities for adaptation.
The discoveries on this lake are also a reminder that life can persist in unexpected places. This opens the way for new research into extremophilic microorganisms and their abilities to survive in increasingly inhospitable environments.
What are Patescibacteria?
Patescibacteria are a group of microorganisms belonging to a very particular bacterial superphylum. Their name comes from their extremely simple cellular structure and microscopic size.
These bacteria are distinguished by their reduced genome, which limits their biological functions. They often need to interact with other organisms to survive, adopting symbiotic or parasitic lifestyles.
They are found in extreme environments, such as the glacial lakes of Antarctica. Their ability to thrive in these conditions makes them a subject of study to understand the limits of life on Earth.
The discovery of Patescibacteria in Lake Enigma shows how resilient these bacteria are, while highlighting the importance of their role in isolated aquatic ecosystems.
