Microbes found in Arctic meteor crater could help point to life on Mars.
Scientists studying an ancient meteorite crash site in the Canadian Arctic have detected traces of microbes that point to the key role played by impact craters in the evolution of life on Earth and could help determine whether life once existed on Mars.
The discovery — hailed by an 11-member team of researchers from Canada, Britain, the United States and Sweden as a scientific “first” — was made at Devon Island’s Haughton Crater, a uniquely dry and desolate geological gem probed frequently by experts from NASA because of its Mars-like features.
“Meteorite impact craters have been proposed as possible sites to find microbial life on Mars, as they are a focus for heat and water circulation,” says the research team, including University of Western Ontario geologist Gordon Osinski.
The researchers examined meteorite-shocked rocks from numerous sites throughout the 24-kilometrewide crater and found telltale traces of sulphur left behind by heat-loving, “thermophilic” bacteria that moved into the crash site after the impact.
“Evidence of widespread microbial activity” in the Canadian crater, the team says, has “shown for the first time that a crater was pervasively colonized by microbes, and that colonization of over 20 cubic kilometres of impact rock was rapid, within 10,000 years after impact, while the rock was still warm.”
The team concludes: “This emphasizes the potential of impact craters in the evolution of early life on Earth, and the search for life on other planets.”
Several of the researchers, including team leader John Parnell of the University of Aberdeen, have made previous findings at the Haughton Crater, highlighting its value in the search for extraterrestrial life as well as in detecting signs of tiny, primordial organisms from the dawn of Earth history.
In 2005, a Parnell-led study at the Nunavut site yielded proof that billion-year-old “biomarkers” — faint chemical traces of organic matter — had survived the massive meteor strike that created the Haughton crater 23 million years ago.
The latest project has yielded proof that the space rock that struck Devon Island created warm, protective niches for microscopic organisms, allowing them to flourish — and leave fossilized signatures of their activity –at the impact site.
The remoteness and “polar desert” environment of Devon Island means the crater has undergone much less change than other impact sites around the world, making it one of the best places on Earth to study a simulated Martian landscape.
Spacecraft that have probed Mars in recent years have fuelled a belief among experts the planet once had water and supported rudimentary forms of life.
Scientists seeking signs of extraterrestrial life are increasingly focused on developing techniques to detect infinitesimally small organisms, fossilized remnants of microbes or merely the faint traces of the biochemical building blocks needed as a base for life’s primordial soup.
In 2004, British scientist Charles Cockell described Devon Island as one of the Earth’s best remaining examples of “the sort of habitat that would have given rise to life on Earth.”
And based on his studies of the Haughton Crater, Mr. Cockell stated at the time such impact sites offer a warm, hospitable habitat for bacteria and algae, and also for the “pre-biotic” proteins that had to come together for that first spark of life on Earth.
Randy Boswell
Canwest News Service
