[LINK] "Ancient Martians May Have Been Hydrogen Powered"

[rfmcdonald]

Discovery.com's Markus Hammonds writes about a chemical reaction that creates energy that might well support life on Mars. (More here.)

A group of researchers led by Lisa Mayhew, of CU Boulder, has identified a particular chemical reaction that may take place between iron-containing minerals and water, which produces hydrogen gas. So much hydrogen gas, in fact, that it could potentially support life in underground habitats — either here on our own planet, or in similar ecological niches on Mars.

Specifically, this chemical reaction is known to occur between seawater and igneous rocks under the ocean floor. Near hydrothermal vents, at high temperatures, the rocks release iron ions into the water that react with the surrounding water to produce iron oxides and hydrogen gas.

While this hydrogen (dissolved in the water) is produced in regions too hot for life to flourish (over 200°C), it seeps out from the rocks into cooler regions where some microbes are already known to be sustained by it. Mayhew and her colleagues have found the first evidence that this reaction can work perfectly well at lower temperatures too. She explains, ”Water-rock reactions that produce hydrogen gas are thought to have been one of the earliest sources of energy for life on Earth.”

“However,” she elaborated, “we know very little about the possibility that hydrogen will be produced from these reactions when the temperatures are low enough that life can survive. If these reactions could make enough hydrogen at these low temperatures, then microorganisms might be able to live in the rocks where this reaction occurs, which could potentially be a huge subsurface microbial habitat for hydrogen-utilizing life.”

With a reaction like this happening so easily, it gives some interesting insight into how primitive life may have survived on the infant Earth — and if primitive terrestrial life could have survived this way, then primitive Martian life could have just as easily done the same.

Could hydrogen-powered life have lived on Mars? Currently, the possibility still can’t be ruled out. A mechanism like this one could certainly have provided a plentiful supply of energy for indigenous martian microbes. Mayhew and her team found that hydrogen could be produced at temperatures in the range of 50-100°C, by rocks containing a specific mineral called spinel.

Spinels are a common type of mineral found on both Mars and Earth (they’re often found together with rubies here on our own planet). On close investigation, the researchers found that the spinels helped facilitate the formation of hydrogen, allowing the reaction to proceed even at lower temperatures than it had been observed before.