Far beneath more than a kilometer of ice in West Antarctica, in a lake that the sun has never touched and the ocean has never fed, a community of microbes has been quietly making a living. Researchers who drilled down to Mercer Subglacial Lake and brought up its cells have now read their genetic inheritance, and the story it tells is one of strangers: mostly species unknown to science, shaped by long isolation rather than recent arrival. It is a reminder that life tends to find its footing even where the conditions seem to forbid it, and that the frozen margins of our planet may hold chapters
Genomes Reveal Flexible, Isolated Microbes Thriving Beneath the West Antarctic Ice Sheet
Most of these genomes belonged to species not described before
Mark
Why does it matter that they got 1,374 genomes rather than just a few?
Mimi
Because each one comes from a single cell. That gives a view of a whole community, and most of what they found turned out to be species nobody had described.
Luke
Worth being careful there. The report says most were new, but it doesn't give an exact count or share. "Most" is all we have.
Mark
How do these microbes get energy without sunlight?
Mimi
Mainly by oxidizing inorganic chemicals like reduced sulfur, iron and carbon monoxide. But they can also switch to organic food like sugars or fats when it's there.
Luke
Keep in mind this comes from genomic data. The genes show what the cells can do. The report doesn't say it measured these activities directly in the lake.
Mark
And the oxygen tolerance?
Mimi
They seem to cope with anything from plenty of oxygen to none, which is unusual flexibility for something living in a sealed lake.
Luke
"Seem" is the right word. Also, this is one lake, Mercer. Whether other subglacial lakes look the same isn't addressed.
Mark
What does independent evolution mean here?
Mimi
Their lineages are genetically separate from marine and surface relatives, so they developed on their own under the ice.
Luke
Fair, though the source doesn't say how long that isolation lasted. That timeline is still unknown.
El Pulso
- Drilling through 1,087 meters of ice to reach a lake sealed off from sunlight and surface food sets the stakes of the entire expedition.
- Most of the 1,374 single-cell genomes belong to species no one has described before, challenging assumptions about what lives in these waters.
- The microbes move between inorganic chemicals and organic food and tolerate anything from abundant oxygen to none, a survival toolkit built for scarcity.
- Genetic distance from marine and surface relatives points to independent evolution, and that finding is now shaping how researchers plan future subglacial exploration.
Far beneath more than a kilometer of ice in West Antarctica, in a lake that the sun has never touched and the ocean has never fed, a community of microbes has been quietly making a living. Researchers who drilled down to Mercer Subglacial Lake and brought up its cells have now read their genetic inheritance, and the story it tells is one of strangers: mostly species unknown to science, shaped by long isolation rather than recent arrival. It is a reminder that life tends to find its footing even where the conditions seem to forbid it, and that the frozen margins of our planet may hold chapters of the living world that have been developing on their own terms for a very long time.
To reach Mercer Subglacial Lake, researchers had to drill through 1,087 meters of ice beneath the West Antarctic Ice Sheet. What they brought back was a collection of microbial cells, and the genetic story they carry has now been published in Nature Communications.
The lake is cut off from the surface. Sunlight never reaches it, and no steady supply of food arrives from the ocean. Earlier drilling in western Antarctica had hinted that life there was active, but how it survived on so little energy remained a puzzle.
The team sorted individual bacterial and archaeal cells and sequenced their DNA, producing 1,374 single-cell genomes. Most belonged to species never described before. Their metabolism proved remarkably adaptable: they generate energy by oxidizing inorganic compounds such as reduced sulfur, iron, and carbon monoxide, yet can also switch to organic food like sugars or fats when available. They tolerate oxygen levels from plentiful to none.
Phylogenetic analysis revealed that these microbes are genetically distinct from their marine and surface relatives, suggesting they evolved independently under the ice rather than arriving recently. The researchers hope these findings will guide how future expeditions explore subglacial lakes.
To reach Mercer Subglacial Lake, researchers had to drill through 1,087 meters of ice beneath the West Antarctic Ice Sheet. What they brought back from the water and sediment below was a collection of microbial cells, and the genetic story those cells told is now published in Nature Communications.
The lake is cut off from the surface. Sunlight does not reach it, and it has no ready supply of food from the ocean or from surface waters. Earlier drilling projects in western Antarctica had offered hints that microbial communities in subglacial lakes were metabolically active. What was not clear was how they stayed alive in an environment so short on energy.
The researchers set out to answer two questions: what metabolic activity sustains these organisms, and whether isolation has shaped their evolution. They sorted individual microbial cells from the samples using flow cytometry. The cells came from bacteria and from archaea, which are single-celled organisms without a nucleus. The team then made multiple copies of the DNA from each cell and analyzed it. The result was 1,374 single-cell amplified genomes, known as SAGs.
Most of those genomes belonged to species that had not been described before. They also carried a notably flexible set of metabolic tools, which allow the organisms to survive in darkness, in isolation, and without oxygen.
The genomes point to chemolithotrophy as a central strategy, meaning the microbes generate energy by oxidizing inorganic chemicals. The compounds they draw on include reduced sulfur, iron, and carbon monoxide, which they use to make food and energy. But the genetic data show that their diet is not limited to these. Depending on what is available, the microbes can switch between inorganic chemicals and organic food such as sugars or fats.
The flexibility extends to oxygen as well. The organisms appear able to survive across a wide range of oxygen levels, from plentiful to none at all.
The team also ran a detailed phylogenetic analysis, which traces evolutionary history. It showed that the lake's microbes are genetically distinct from their marine and surface relatives. They appear to have evolved independently in the subglacial environment rather than arriving recently from elsewhere.
Taken together, the findings give a detailed picture of how life persists and adapts beneath the frozen landscape of West Antarctica. Genetic isolation of this kind may inform how scientists approach future exploration of subglacial lakes.
Citas Notables
The microbes were genetically isolated from surface and marine life and had evolved independently in their subglacial environment.— Researchers' phylogenetic analysis, as reported by Phys.org
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