Rock-Eating Life?
(From the November/December 1998 issue of StarDate magazine)
Two recent discoveries on Earth strengthen the possibility that rock-eating microbes could exist beneath the surfaces of Mars, Europa, or other planets or moons.
Scientists at Oregon State University recently found evidence of microscopic organisms living almost a mile beneath the floors of the Pacific, Atlantic, and Indian Oceans. They found tiny cracks and trails inside glassy basalt, a type of volcanic rock, in core samples from several research groups. Within those trails, the scientists found DNA, but no living organisms.
The basalt contains the basic elements for life, including carbon, nitrogen, and phosphorous. The other critical element, water, could percolate down from the ocean floor. Microscopic organisms may digest the rock for nutrients or energy, the scientists report. With heat, water, and nutrients, it's possible that similar rock-eating microorganisms could have evolved on other worlds, the scientists say. The scientists hope to drill new core samples and find microorganisms living within the rock.
Just one month after publication of the Oregon State report, University of Massachusetts microbiologist Derek Lovley announced that some subterranean microorganisms can use iron to convert their food into energy. The microbes are called hyperthermophiles, which means they thrive in hot conditions.
Hyperthermophiles are closely related to the first microscopic life on Earth. Lovley says his findings indicate that early life on Earth needed iron to grow and survive. Hyperthermophiles converted iron into magnetite, a magnetic mineral. -- — Damond Benningfield
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