A plan of life on Mars?

A plan of life on Mars?

Microbes taken from surface sediment near Lost Hammer Spring, Canada, about 900 km south of the North Pole, can give a blueprint for the type of life forms that may have once existed, or may still exist, on Mars. Credit: Elisse Magnuson.

The extremely salty, very cold and almost oxygen-free environment during the permafrost of Lost Hammer Spring in Canada’s high arctic area is what is most similar to certain areas on Mars. So if you want to learn more about the kinds of life forms that once could have existed – or still can exist – on Mars, this is a good place to look. After much searching under extremely difficult conditions, researchers from McGill University have found microbes that have never been identified before. By using advanced genomic techniques, they have also gained insight into their metabolism.

In a recent article in ISME Journal, scientists demonstrate for the first time that microbial communities living in Canada’s high arctic regions, under conditions analogous to those on Mars, can survive by eating and breathing simple inorganic compounds of a type that have been discovered on Mars (such as methane) sulfide , sulfate, carbon monoxide and carbon dioxide). This discovery is so compelling that samples of Lost Hammer surface sediments were selected by the European Space Agency to test the life detection capability of the instruments they plan to use on the next ExoMars mission.

Develops a plan for life on Mars

Lost Hammer Spring, in Nunavut in Canada’s high arctic area, is one of the coldest and saltiest terrestrial springs discovered to date. The water that travels up through 600 meters with permafrost to the surface is extremely saline (~ 24% salinity), perennial at temperatures below zero (~ -5 ° C) and contains almost no oxygen (water habitat even at minus degrees) These conditions are analogous to the found in certain areas of Mars, where widespread salt deposits and possible cold salt sources have been observed. And while previous studies have found evidence of microbes in this type of Mars-like environment, this is one of very few studies to find microbes alive and active.

To gain insight into the kinds of life forms that can exist on Mars, a research team from McGill University, led by Lyle Whyte at the Department of Natural Resources Sciences, has used state-of-the-art genomic tools and single-cell microbiological methods to identify and characterize a new, and more importantly, active microbial community this unique spring. Finding the microbes and then sequencing their DNA and mRNA was no easy task.

It requires an unusual way of life to survive in difficult conditions

“It took a couple of years of work with the sediment before we were able to detect active microbial communities,” explains Elisse Magnuson, a Ph.D. student in White’s lab, and the first author on paper. “The salinity of the environment interferes with both the extraction and sequencing of the microbes, so when we were able to find evidence of active microbial communities, it was a very satisfying experience.”

The team isolated and sequenced DNA from the spring community so that they could reconstruct genomes from approximately 110 microorganisms, most of which have never been seen before. These genomes have enabled the team to determine how such creatures survive and thrive in this unique extreme environment, serving as drawings for potential life forms in similar environments. Through mRNA sequencing, the team was able to identify active genes in the genomes and essentially identify some very unusual microbes that actively metabolize in the extreme spring environment.

No need for organic material to support life

“The microbes we found and described at Lost Hammer Spring are surprising because, unlike other microorganisms, they do not depend on organic matter or oxygen to survive,” Whyte adds. “Instead, they survive by eating and breathing simple inorganic compounds such as methane, sulfides, sulfate, carbon monoxide and carbon dioxide, all of which are found on Mars. They can also fix carbon dioxide and nitrogen gases from the atmosphere, all of which make them highly adapted to both survive and thrive in extreme environments on earth and beyond. “

The next steps in the research will be to cultivate and further characterize the most numerous and active members of this strange microbial ecosystem, to better understand why and how they thrive in the very cold, salty, dung of Lost Hammer Spring. The scientists hope that this in turn will help in the interpretation of the exciting but enigmatic sulfur and carbon isotopes that were recently retrieved from NASA Curiosity Rover in the Gale crater on Mars.


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More information:
Elisse Magnuson et al., Active lithoautotrophic and methane oxidizing microbial community in an anoxic, sub-zero and hypersaline high arctic spring, ISME Journal (2022). DOI: 10.1038 / s41396-022-01233-8

Provided by McGill University

Citation: A blueprint for life forms on Mars? (2022, June 21) retrieved June 21, 2022 from https://phys.org/news/2022-06-blueprint-life-mars.html

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