Never-before-seen microbes living deep under the permafrost at one of the coldest and saltiest water sources on Earth could provide a blueprint for life on Mars.
At Lost Hammer Spring, which sits above the Arctic Circle in Nunavut, Canada, saltwater bubbles up through 600 meters of permafrost. The water has a salinity of about 24% and the salt acts as an antifreeze, so the water remains liquid even at temperatures below freezing. But it’s the lack of free oxygen — less than 1 part per million — that makes the conditions there truly alien.
Indeed, its cold, salty and oxygen-free environment makes Lost Hammer Spring one of Earth’s closest analogues Marswhich is widespread salt deposits left by old water† And some researchers have argued that: changes observed in gullies and dark stripes on the slopes of crater walls could have come from saltwater welling up from the ground, similar to the source at Lost Hammer, although many scientists prefer dry avalanches as perhaps a more likely explanation.
Now, a team of scientists has found microbial life in the extreme conditions of Lost Hammer Spring and mapped the genomes of about 110 organisms living there, revealing clues as to how life could potentially survive in Mars’ harsh environment. .
Although microbes have been discovered in Mars-like conditions on Soil previously this was one of the first studies to establish that these ‘extremophiles’ are active in such an inhospitable environment.
“It took a few years of working with the sediment before we were able to successfully detect active microbial communities,” said Elisse Magnuson, a doctoral student at McGill University in Montreal and lead author of a new study describing the findings, in a paper. pronunciation (opens in new tab)†
To survive the harsh conditions of Lost Hammer Spring, the microbes are anaerobic, meaning they don’t breathe oxygen. Instead, they consume methane and other inorganic compounds, such as carbon dioxide, carbon monoxide, sulfate and sulfide, all of which are found on Mars, to power their metabolism.
In particular, the presence of methane on Mars is an unsolved mystery; scientists are divided on whether the origin is geological or biological. The sediment in the permafrost at Lost Hammer Spring is continuously emitting gases containing methane and could provide further clues as to the origin of the detected methane plumes on Mars.
“The microbes we found and described at Lost Hammer Spring are surprising because, unlike other organisms, they do not depend on organic matter or oxygen to live,” Lyle Whyte, who led the research team and the Canadian Research Chair in polar microbiology is at McGill University, said in the statement. “They can also repair [i.e., convert into organic molecules] carbon dioxide and nitrogen gases from the atmosphere, making them well suited to both survive and thrive in very extreme environments on Earth and beyond.”
The results provide a genetic blueprint for how microbial life might survive — today or in the past — on Mars. The findings are so compelling that scientists working on the delayed Rosalind Franklin ExoMars rover tests its life-detection capabilities on samples of the microbes found at Lost Hammer Spring.
The findings were published on April 8 in The ISME Journal (opens in new tab)I†
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