Animals could be living on Mars

Gold mine worm
“It’s like finding Moby Dick in Lake Ontario,” says Tullis Onstott.University team discovered living far beneath the Earth’s surface in South Africa. The tiny worms – just 500 micrometres long – were found at depths ranging from 900 metres to 3.6 kilometres, in three gold mines in the Witwatersrand basin near Johannesburg. That’s an astonishing find given that multicellular organisms are typically only found near the surface of the Earth’s crust. The creatures seem to live in water squeezed between the mines’ rocks, can tolerate temperatures reaching 43 °C and feed off bacteria. Carbon dating of compounds dissolved in the water suggests that the worms have been living at these depths for between 3000 and 12,000 years.”To have complex life sustain itself for such a long period completely sealed away from everything else – from sunlight, from surface chemistry – is pretty amazing,” says Caleb Scharf of the Columbia Astrobiology Center in New York City. “We’ve had this preconception that there can only be certain types of organisms in certain environments,” says Scharf. “But it’s not true at all. There are more complex organisms in these bizarre environments.”If complex life forms are able to survive inside cracks deep inside Earth, it raises the possibility that they might have survived undetected in similar environments on Mars. Carl Pilcher, director of NASA’s Astrobiology Institute in Moffett Field, California, points out that Onstott has previously discovered a bacterium living 2.8 kilometres underground, completely isolated from all other ecosystems on Earth. The bug gets its energy from the radioactive decay of elements in the surrounding rocks. “The significance was that you could imagine an ecosystem existing in the subsurface of a planet that didn’t have a photosynthetic biosphere, like Mars,” he says.Until now, it was thought such an ecosystem could be made of bacteria only. But Onstott’s new findings have completely changed that. “It has extended the [earlier] work to an animal,” says Pilcher. “These nematodes are grazing on microbes. So now you could imagine that if animal life had ever developed on a planet, and the surface of that planet became lifeless,” Pilcher explains, “you could imagine that animals [small enough to fit in tiny cracks] could coexist with microbial ecosystems all powered by radioactivity.”
Source: www.newscientist.com, June 2, 2011

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