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Antarctica’s Lake Enigma, situated between the Amorphous and Boulder Clay glaciers, is characterized by its consistently low temperatures, averaging around 7 degrees Fahrenheit and plunging to as low as -41 degrees in winter. Historically regarded as a frozen wasteland devoid of life, recent findings suggest that at least some microbiotic organisms have adapted to survive in these harsh conditions.
A team of scientists from the National Research Council of Italy’s Institute of Polar Sciences made significant discoveries during the “XXXV Italian Expedition to Antarctica,” conducted from November 2019 to January 2020. Initially believing the lake to be completely solid and lifeless, the researchers employed ground-penetrating radar, which revealed the existence of liquid water beneath ice layers that could be up to 36 feet deep. This led to the identification of stratified water columns extending below the ice.
To gather uncontaminated water samples, the researchers used a specially designed thermal melt head drilling system. This innovative tool allowed them to penetrate the ice while maintaining the integrity of the samples, setting the stage for a series of underwater surveys and analyses.
Findings were published on December 3rd in the journal Communications Earth & Environment, where the research team documented the presence of 21 bacterial and eukaryotic phyla within the lake’s ice and water layers. Among the identified organisms were Pseudomonadota, Actinobacteriota, and Bacteroidota. Notably, the researchers found a remarkable abundance of a unique bacterial superphylum, Patescibacteria, which consists of simple lifeforms with minimal metabolic functions due to their small genomes.
The authors note that these bacteria likely lead an obligate symbiotic or predatory existence, relying heavily on interactions with prokaryotic host cells for survival. This symbiotic relationship is crucial for their life in the extreme conditions of Lake Enigma.
The research team hypothesizes that Lake Enigma may have previously supported a richer, more diverse ecosystem before its surface froze permanently. This suggests that the current microbial community could be a remnant of a more complex biological landscape that existed in the past.
[Related: What will Antarctica look like in 2070?]
The researchers conclude that the lake’s ice-encased microbiota represents a continuation of ancient biological lineages, providing insight into a simplified aquatic food web. Additionally, some microbial species may perform ecological functions that are unprecedented in other Antarctic ice-covered lakes. As further studies are planned, the implications of these discoveries could extend our understanding of extreme life and the evolutionary history of isolated ecosystems.
Source
www.popsci.com