An Antarctic lake represents a time capsule that holds the secrets of ancient life, a fossil trace of the living community that populated the region before the lake was sealed by ice. This is what a study published in the “open access” journal Communications Earth & Environment, which is part of the Nature group, reveals. The lake in question is Lake Enigma.
Lake Enigma in Antarctica
Lake Enigma, until recently considered completely frozen, has revealed a surprising secret: under 11 meters of permafrost there is a large body of liquid water (at least 12 meters deep), clearly stratified and poor in nutrients.
Lake Enigma is located in Antarctica, not far from the northern foothills, about 5 kilometers from the Italian Mario Zucchelli base. Lake ENIGMA owes its name to the enigmatic presence of a raised debris cone in its center, considered completely frozen since 1989.
The drilling, carried out by researchers at different points of the lake during the XXXV Italian Antarctic Expedition (November 2019 – January 2020), and carried out adopting a rigorous sampling protocol in Antarctic subglacial environments, made it possible to sample the surface of the ice, the different layers of the water column and the well-developed “microbial mats” at the bottom.
Geochemical analyzes have shown that the lake basin is isolated from the atmosphere and exhibits marked thermal and chemical stratification. Microbiological analyzes showed that Lake Enigma is home to an extremely diverse and abundant microbial ecosystem, unique among Antarctic subglacial lakes.
A unique microbial ecosystem
In particular, the microbial community of the lake is enriched in ultramicroscopic bacteria of the Patescibacteria superfile, also known as Candidate Phyla Radiation (CPR); simple organisms with a small genome, never before discovered in perpetually frozen lakes before this study.
This discovery highlights the complexity and diversity of food webs in Antarctica’s permafrost lakes, with both symbiotic and predatory lifestyles.
The study, funded by the National Antarctic Research Program (NARP), was carried out by the Cnr Polar Sciences Institute (Cnr-Isp) in collaboration with the National Institute of Geophysics and Volcanology (INGV), the Water Research Institute (Cnr-Irsa), the Southern Illinois University (United States) and Queen’s University Belfast (Ireland).
“Fed by the melting of the Amorphous glacier, Lake Enigma could harbor a microbial community composed of a mixture of ancient organisms, native to the lake itself, and new arrivals from the glacier,” say the authors of the article. “However, this hypothesis, although intriguing, requires additional studies to be confirmed.
New knowledge, both from an earthly and extraterrestrial perspective
This type of study and discovery offers new perspectives from both an “terrestrial” and “extraterrestrial” point of view. This type of habitat where “extremophile” organisms can survive or proliferate is also possible in other similar environments.
Indeed, let’s think of Europa, one of Jupiter’s natural satellites, or of Enceladus (a moon of Saturn), where, under their polar caps, There are indications of habitats similar to those of Lake Enigma and which could therefore harbor extraterrestrial (microbial) life forms.
Article reference:
– Smedile, F., La Cono, V., Urbini, S. et al. The perennially ice-covered Lake Enigma, Antarctica supports unique microbial communities. Commun Earth Environ 5741 (2024).
