Ancient Frozen Lake Preserves a Time Capsule From Millions of Years Ago

Beneath Antarctica’s Lake Enigma, a hidden freshwater ecosystem has been sealed under 30 feet (9 meters) of ice for up to 14 million years. Led by Italian scientists, researchers used radar and advanced, contamination-free drilling methods to access and study this ancient, isolated biome.

Analysis shows Lake Enigma hosts a phylogenetically diverse, high-biomass microbial ecosystem distinct from any other ice-covered Antarctic lake. Researchers suggest these microbes are remnants of an ancient ecosystem that thrived before the lake froze over. The microbial community forms a simple food web, ranging from photosynthetic organisms to predators and symbiotic species.

Unveiling Microbial Dark Matter: Patescibacteria and Other Unique Microbial Groups Thrive in Lake Enigma

Key microbial groups discovered include Pseudomonadota, Actinobacteriota, and Bacteroidota. Most notably, an unexpected abundance of Patescibacteria thrives despite the water column’s unusually high levels of dissolved oxygen. Furthermore, these tiny, symbiotic bacteria—often referred to as “microbial dark matter“—appear to play unique and critical roles in this extreme environment.

Underwater imaging revealed the lake floor covered in diverse microbial mats, dominated by oxygen-producing cyanobacteria absent in the water column and ice. These mats form crumpled carpets, towering structures up to 2 feet tall, and dune-like pinnacles. The stable, pressurized ecosystem, likely fed by meltwater from the nearby Amorphous Glacier, includes elusive Patescibacteria, ultrasmall symbiotic microbes that may play unique roles in Lake Enigma’s extreme conditions.

Read Original Article: Science Alert

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