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The discovery of methane-eating bacteria in a very unique region of Canada’s extreme north supports the theory that similar organisms could be on Mars. Researchers have found methane-eating bacteria in a cold, methane filled spring located on Axel Heiberg Island in Canada, and say the spring is similar to possible past or present springs on Mars, and that therefore they too could support life.
The spring, called Lost Hammer supports microbial life. It is so salty that it doesn’t freeze despite the cold, and it has no consumable oxygen in it, said Dr. Lyle Whyte from McGill University in Montreal. There are, however, big bubbles of methane that come to the surface, which made the research team – which also included scientists from National Research Council of Canada, the University of Toronto and the SETI Institute –curious as to whether the gas was being produced geologically or biologically and whether anything could survive in this extreme hypersaline subzero environment.
“We were surprised that we did not find methanogenic bacteria that produce methane at Lost Hammer,” Whyte said, “but we did find other very unique anaerobic organisms – organisms that survive by essentially eating methane and probably breathing sulfate instead of oxygen.”
The discoveries of methane and frozen water on Mars, along with recently formed gullies are similar to what is occurring on Axel Heiberg Island. The methane on Mars is quite intriguing since the short-lived gas is obviously being replenished in some way.
But just the fact that methane is on Mars could mean the planet could support life.
“The point of the research is that it doesn’t matter where the methane is coming from,” Whyte explained. “If you have a situation where you have very cold salty water, it could potentially support a microbial community, even in that extreme harsh environment.”
The Lost Hammer spring region is very analogous to Mars. “There are places on Mars where the temperature reaches relatively warm -10 to 0 degrees and perhaps even above 0 degrees C,” Whyte said, “and on Axel Heiberg it gets down to -50, easy. The Lost Hammer spring is the most extreme subzero and salty environment we’ve found. This site also provides a model of how a methane seep could form in a frozen world like Mars, providing a potential mechanism for the recently discovered Martian methane plumes.”
Source: McGill University
For this conjecture to be corrent the methane must be generated by geological means. I presume this would require Mars to be somewhat geologically active.
LC
Interesting to read this story and contrast it to recent work on the possibility of methane-based life on Titan by Chis McKay.
“To date, methane-based life forms are only hypothetical. Scientists have not yet detected this form of life anywhere, though there are liquid-water-based microbes on Earth that thrive on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin (minus 290 degrees Fahrenheit), a methane-based organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan’s surface and much too cold to support life as we know it.
The list of liquid candidates is very short: liquid methane and related molecules like ethane. While liquid water is widely regarded as necessary for life, there has been extensive speculation published in the scientific literature that this is not a strict requirement.”
It sure makes for some interesting speculation! “What is Consuming Hydrogen and Acetylene on Titan?” here: http://www.physorg.com/news194801328.html
More could-be’s, may-be’s and perhaps. It’s bloody long long stretch to say there’s microbial life on Mars because we’ve found the same in what appear to be analogous conditions on earth. Until we find conclusive proof that this is or was life on Mars it’s all mere speculation and trying to conclussions for a dead planet from a fully functioning one borders on the pointless.
As usual, I have concerns for methane metabolism scenarios. That the discussion moves from methanogens to methanotrophs doesn’t help that much.
Evolution can add and remove traits, but whole metabolic chains are hardly targets for, say, horizontal gene transfer. Phylogenetically methylotrophy is one enzyme simpler, so it is the likely starting point. From methanotrophy to methanogenesis there is a conserved core.
The methylotrophy and methanotrophy described so far is aerobic. Since anaerobic methanotrophy is nested within methanogenesis it must be younger.
While there is no full cladistic description of the phylogenetic roots of life, larger mappings of Martin et al shows archaebacteria and eukaryotes as sisters.
That makes sense of the metabolic phylogeny here, as bacterial aerobic methanotrophs can scavenge methane from the atmosphere down to 20 ppm.
Using oxygen is more effective, and it is then likely that methylotrophs and methanotrophs first evolved when photosynthesis allowed for so much metamorphosing organics that local levels of the nutrients were reasonable. Loss of these metabolic pathways is more parsimonious than if the LUCA has this capability.
Later archaebacteria, putatively cladistically on the tree that retained methanotrophy, evolved methanogenic metabolism under anaerobic conditions. Finally eukaryotic multicellularity created a large and easy niche for such methanogens to evolve anaerobic methanotrophy. There I suspect we find most of them today, in the stomach of the ruminants that AFAIU also harbor the methanogens.
Perhaps bacteria on Mars could evolve all the way to sulfur based methanotrophy before the environment became too harsh and oxygen deprived. Sulfur based metabolism was likely late on Earth, Earth has little sulfur on account of its Fe/FeS core formation, and AFAIU the traces of such organisms starts from ~ 2 Ga.
But the way to bet is that it didn’t happen. Eukaryotes are ~ 1 Ga, so that is when the sister clade archaebacteria took off. Mars hadn’t much time for such elaborate developments.
Get a load of this recent (April 2010) work on dear old ALH84001:
“Martian meteorite ALH84001 (ALH) is the oldest known igneous rock from Mars and has been used to constrain its early history. Lutetium-hafnium (Lu-Hf) isotope data for ALH indicate an igneous age of 4.091 ± 0.030 billion years, nearly coeval with an interval of heavy bombardment and cessation of the martian core dynamo and magnetic field. The calculated Lu/Hf and Sm/Nd (samarium/neodymium) ratios of the ALH parental magma source indicate that it must have undergone extensive igneous processing associated with the crystallization of a deep magma ocean. This same mantle source region also produced the shergottite magmas (dated 150 to 570 million years ago), possibly indicating uniform igneous processes in Mars for nearly 4 billion years. [My bold]”
Possibly somewhat geologically active, yes.
The Titan observations I like however.
That a loss from pathways that is already a partial set on account of being younger than the LUCA is more parsimonious is btw also more rigorously treated in the paper on the methane metabolism core (1st link), which have the actual phylogenetic outcome mapped.