Gold-mine worm “Nematode” shows life could be living on Mars

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 Tullis Onstott has previously discovered a bacterium living 2.8 kilometers underground, completely isolated from all other ecosystems on Earth (Science, DOI: 10.1126/science.1127376).

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 Tullis 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.” Journal reference: Nature, DOI: 10.1038/nature09974

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 Tullis Onstott has previously discovered a bacterium living 2.8 kilometers underground, completely isolated from all other ecosystems on Earth (Science, DOI: 10.1126/science.1127376). 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 Tullis 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.” Journal reference: Nature, DOI: 10.1038/nature09974Due to the expense and contamination associated with coring from the surface, few microbial rock and water samples have been collected from depths greater than 0.5 kilometers. These few samples, nevertheless have demonstrated that microbial communities do exist in a variety of subsurface rocks and sediments down to 2.8 kilometers below the surface