MICROBES could play a big role in the future of Mars. Genetically engineered
bacteria may be the first creatures to colonise the Red Planet, while
rock-eating bugs could help release carbon dioxide from its crust.
Once planetary engineers have begun to make Mars warmer and moister, special
bacteria could colonise its surface, says molecular biologist Julian Hiscox of
the University of Reading. 鈥淲e鈥檇 take bacteria living in conditions nearest to
Mars and play Darwin, getting them closer by selection and genetic engineering,鈥�
he says.
Antarctic bacteria, for instance, already endure temperatures well below
freezing. By growing these cells at ever lower temperatures and selecting those
that thrive, it will be possible to breed bugs suited to an extraterrestrial
existence, Hiscox says.
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The tools of molecular biology could improve them further, by stealing traits
from other terrestrial bacteria that could give them a vital edge on Mars. The
wish list includes: a tolerance of harsh chemicals, resistance to dryness and
radiation, and the ability to produce ultraviolet-absorbing proteins.
As well as protecting the cells, such UV 鈥渟unscreen鈥� proteins could power
them too, suggests Penelope Boston of the University of New Mexico in
Albuquerque. These proteins could be coupled to the existing photosynthetic
machinery in bacteria, she says.
Boston also thinks that rock-digesting bacteria she has found in caves could
help recycle trapped CO2 in Mars鈥檚 crust, helping to warm the planet.
On Earth, CO2 and other gases are released by the movement and
re-cooking of huge tectonic plates, but Mars doesn鈥檛 have any similar tectonic
activity. So she proposes establishing a 鈥渂iotectonic鈥� cycle instead, using
communities of these microbes. 鈥淭heir work is extremely rapid,鈥� Boston says.
When you walk by cave walls where these bacteria live, she says, 鈥渢he rock is
literally raining down鈥�.
