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Hot Topic Solar System Mars The Greening of the Red Planet
The Greening of the Red Planet
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Posted:   01/23/01
Author:    Henry Bortman

Summary: A hardy microbe from Earth may one day transform the barren ground of Mars into arable soil.

Although Mars may once have been warm and wet, the red planet today is a frozen wasteland. Most scientists agree that it's highly unlikely that any living creature, even a microbe, could survive for long on the very surface of the planet.

When the first humans travel to Mars to explore the red planet up close, they will have to grow their food in airtight, heated greenhouses. The Martian atmosphere is far too cold and dry for edible plants to grow in the open air. But if humans ever hope to establish long-term colonies on their planetary neighbor, they will no doubt want to find a way to farm outdoors. Imre Friedmann has an idea of how they might take the first step.

Imre Friedmann
Astrobiologist Imre Friedmann sees his research into terraforming Mars as a "thought experiment." Credit: Florida State University.

Friedmann is a microbiologist who recently joined the NASA Astrobiology Institute team at NASA's Ames Research Center. Friedmann was one of the invited speakers at a NASA-sponsored conference, "The Physics and Biology of Making Mars Habitable," held at Ames in October 2000. His talk focused on an organism that could be used to begin the process of converting the Martian surface into arable soil.

Mars is covered by a layer of ground-up rock and fine dust, known as regolith. To convert regolith into soil, it will be necessary to add organic matter, much as organic farmers on Earth fertilize their soil by adding compost to it.

On Earth, compost is made up primarily of decayed vegetable matter. Microorganisms play an important role in breaking down dead plants, recycling their nutrients back into the soil so that living plants can reuse them. But on Mars, says Friedmann, where there is no vegetation to decay, the dead bodies of the microorganisms themselves will provide the organic matter needed to build up the soil.

The trick is finding the right microbe. "Among the organisms that are known today," says Friedmann, "Chroococcidiopsis is most suitable" for the task. Chroococcidiopsis is one of the most primitive cyanobacteria known. Chroococcidiopsis is present in the most extremely arid desert microbial habitats, where no other cyanobacteria can exist.

A photomicrograph of Chroococcidiopsis, enlarged 100 times.

What makes Chroococcidiopsis such a good candidate is its ability to survive in a wide range of extreme environments that are hostile to most other forms of life. Chroococcidiopsis has been found growing in hot springs, in hypersaline habitats, in a number of hot, arid deserts throughout the world, and in the frigid Ross Desert in Antarctica. "Chroococcidiopsis is the constantly appearing organism," Friedmann points out, "in nearly all extreme environments at least extreme dry,extreme cold, and extremely salty environments. This is the one which always comes up."

Moreover, where Chroococcidiopsis survives, it is often the only living thing that does. But it gladly gives up its dominance when conditions enable other, more complex forms of life to thrive.

For clues on how to farm Chroococcidiopsis on Mars, Friedmann looks to its growth habits in arid regions on Earth. In desert environments, Chroococcidiopsis grows either inside porous rocks (endolithic growth), or just underground, on the lower surfaces of translucent pebbles (hypolithic growth).

The pebbles provide an ideal microenvironment for Chroococcidiopsis in two ways. First, they trap moisture underneath them. Experiments have shown that small amounts of moisture can cling to the undersurfaces of rocks for weeks after their above-ground surfaces have dried out. Second, because the pebbles are translucent, they allow just enough light to reach the organisms to sustain growth.

Chroococcidiopsis grows on the undersides of transparent rocks
In many desert environments, Chroococcidiopsis grows on the undersides of transparent rocks, just below the surface.

Friedmann envisions large farms where the bacteria are cultured on the underside of strips of glass that are treated to achieve the proper light-transmission characteristics. Mars today, however, is too cold for this technique to work effectively. Before even as hardy a microbe as Chroococcidiopsis could be farmed on Mars, the planet would have to be warmed up considerably, to just below the freezing point. That process could take hundreds of years.

What's Next

Friedmann admits that his ideas about growing Chroococcidiopsis are, at this point, merely a thought experiment. "I don't think any of us alive today will see this happen," he muses. Neither NASA nor any other space agency has plans even to send humans to explore the red planet, let alone to begin the process of terraforming it.

"When the time does come" to begin the process of terraforming Mars, he explains, "say, 50 years from now, the technology will be so different that everything that we are planning today, with today's technology, will be ridiculously outdated." Friedmann fully expects that by that time "genetic engineering will have developed to the point that we can produce designer organisms" to do the job. Even if Chroococcidiopsis is ultimately used "as the basis, it will be a vastly improved version of today's Chroococcidiopsis.

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Pioneer Organisms Nominated for Terraforming
Describes several microorganisms that might be used in terraforming Mars, including Chroococcidiopsis and Deinococcus radiodurans.

Ionizing-Radiation Resistance in the Desiccation-Tolerant Cyanobacterium Chroococcidiopsis
Abstract of a paper Friedman presented at the First Astrobiology Conference.

Meet Conan the Bacterium
Article describes how the radiation-resistanct microbe Deinococcus radiodurans might be used to explore Mars and even to terraform it.

Terraforming Mars

Thawing Mars
Greenhouse gases might one day be used to warm the cold surface of Mars, and make the planet habitable for humans.

Mars terraformation
Introduction to terraforming Mars. Includes excellent images.

Bringing Life to Mars
Article by NASA astrobiologist Chris McKay from Scientific American, March 1999.

Bringing Mars to Life
Transcript of a public lecture given byChris McKay, March 1999.

Mars, the Final Frontier
Article in New Scientist, February 1994.

The Terraforming Information Pages
A variety of resources on terraforming Mars.

Extensive Literature about Terraforming
Chris McKay's suggested bibliography on terraforming Mars.

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