Terraforming

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Planetary Engineering

Artists rendition of Mars terraformation (galaxyexplorers.org).

Terraforming or “Planetary Ecosynthesis” is the process of changing a planet’s atmosphere to resemble that of the Earth’s, with the goal of sustaining terrestrial life. It is predicted that establishment of life will be similar to Earth’s history, starting with basic unicellular microorganisms. The most pheasible pioneer to begin life on a new planet would be some kind of photosynthetic microbe.[8]

The strategy of using photosynthesis to engineer a habitable planet for humans through photosynthesis would not be unlike the Great Ogygenation Event that took place on Earth 2.4 billion years ago, sometime after cyanobacteria first evolved (2.7-2.8 billion years ago.) This pivotal event paved the way for evolution of multi-cellular organisms and later, human beings.[4]

The topic has sprung much speculation as well as the ethical debates surrounding the idea.

Candidates for Terraformation

Mars: the winner

Mars is the preferred planet of interest for terraforming because it's history of once being a water planet, and the fact that it still retains much of its CO₂, nitrogen, and H₂O.[8] Currently Mars is very cold and it's atmosphere is relatively thin and mostly consists of CO₂ (95.3%) with very little O₂ and N₂. Mars only receives 43% of the light Earth gets from the Sun, yet it is still sufficient enough for photosynthesis.[10]

Proposed Terraformation of Mars would require:

• Warming the planet substantially


• Increase atmospheric pressure while adding O₂


• Melt water (which Mars has frozen in Ice caps)

[1]

Venus

Venus has been proposed but it’s problems far surpass Mars in that it has a very thick atmosphere, little water, and it’s temperatures are much warmer than Earth.[11] Venus also has clouds made of searing sulfuric acid, and one Venus day is equivalent to 127 Earth days.[2]

Proposed Terraformation of Venus would require:

• Cooling the planet substantially


• Removing CO₂ and other poisonous gases from the atmosphere while replacing it with O₂


• Reduce day length to 24 hours


• Provide water

[2]

Biological interaction

The interaction of pioneering microbial species within an alien atmosphere will hopefully pave the way for future organisms such as plants and eventually humans to be able to colonize that planet.
The primary function of photosynthetic pioneers would be to take CO₂ out of the atmosphere while adding O₂ to the atmosphere.[10]

Niche: A New World

To lay the foundation for microbial terraforming, the agreed plan for Mars begins with:

• the release of man-made greenhouse gases into the atmosphere, heating the planet substantially,
• Initial warming will then cause CO₂ evaporation from the planet’s own glaciers and soil, producing further warming
• Melting glaciers will produce hydrologic cycles and evaporated H₂O into the air, creating a denser atmosphere. This suggests a global temperature of at least 0 degrees Celsius.
• Water will be stable on the surface and temperatures will be more moderate, but the atmosphere will be mostly CO₂ and have little O₂.
So long as UV radiation remains high, microorganisms will be confined to living in or under rocks.[5]
UV radiation screens have been proposed for microbial access to surfaces.[8]
Microbial populations set to colonize Mars can expect extreme cold temperatures, high radiation, little to no moisture, and limited nutrients.[8]

_{http://www.antarcticaedu.com/visions/}

_{http://io9.com/5655719/terraforming-earth-pt-4-nowhere-to-go-but-up}





























Microbial processes

Mars has no tectonic activity so no biogeochemical cycling occurs there. It's thought that biological and photochemical processes can run the cycles on Mars.[10]


Carbon cycling

Photosynthetic microorganisms remove CO₂ from the atmosphere by photosynthesis:
6CO₂ + 12H₂O + Light -> C₆H₁₂O₆ + 6O₂+ 6H₂O
Eventually heterotrophic microbes will release CO₂ back into the atmosphere through respiration:
C₆H₁₂O₆ + 6O₂ --> 6CO₂ + 6H₂O + energy
Certain Microorganisms such as Matteia have been proposed to release CO₂ from carbonate rock to complete the cycle in the early stages of colonization, just until enough carbohydrate is available to support heterotrophs.



Thomas, David J. 1995. "Biological Aspects of the Ecopoesis and Terraformation of Mars: Current Perspectives and Research

Oxygen

Cyanobacteria and algae will be used to increase O₂ through photosynthesis
6CO₂ + 12H₂O + Light -> C₆H₁₂O₆ + 6O₂+ 6H₂O

Nitrogen cycling

Besides CO₂ and O₂, a buffer gas is needed to support human life, and nitrogen is necessary for photosynthesis at the start of terraformation. Currently there is not enough N₂ in Mars' atmosphere for nitrogen fixation and therefore, denitrification is necessary as long as the regolith contains nitrate as is proposed
Denitrification:
NO₃− → NO₂− → NO + N₂O → N₂ (g)
Cyanobacteria can reduce N₂ to ammonia:
N₂ + 8 H+ + 8 e− → 2 NH₃ + H₂

Sulfur cycling

Most microbes utilize oxidized sulfur for protein synthesis.


Phosphorous cycling

Phosphates are insoluble minerals that are highly conserved in stable environments but through time losses can be a possible issue for terraformation. This may be the case with other non-volatile, minerals such as iron, manganese, and magnesium.[10]





Key Microorganisms

Microorganisms are the best option for colonization of a new planet because of their wide range of physiologic and metabolic functions and are capable of horizontal gene transfer. Two strategies have been proposed for choosing the best pioneers. One can either choose a generalist extremophile on Earth that inhabits environments similar to the new planet, or genetically modifying a new species with all the best traits required for the job. (Creating a Genetically Engineered Mars Organism "GEMO")[9]


Proposed traits of the perfect pioneer are:

• Must be photoautotrophs


• Must be anaerobic and respire without O₂


• Osmotic tolerance


• Resistance to UV radiation


• Cold tolerance


• Tolerance for Nutrient limitations


• Tolerance for water limitations


• Resistance to oxides


• Adaptation to lowered intracellular pH due to CO₂ in atmosphere


• Can form Endospores

[9]

Proposed Photoautotrophs

Cyanidium caldarium

A unicellular red algae found in diverse extreme environments such as bogs, wet acidic soils, and hot streams. It has been found to survive with little to no oxygen.[12]


Cyandium Caladarium Algae (Shu Suehiro Botanic.jp)


















Cryptoendolith Lichens

Literally "hiding in rocks" An extremophile found in porous rock in Antarctica where temperatures are normally -89.2°C to -93.4°C. There has been no rain or snowfall in the Antarctic Desert for over 100 years.[3]

Antarctic sandstone inhabited by cryptoendolithic lichen communities. Photo courtesy of NASA



















Chroococcidiopsis

This primitive cyanobacterium has a high range of variability and may be the most desiccant-resistant of it's kind. It is found in extreme habitats such as Antarctic rocks, thermal springs, and hypersaline habitats. [7]


Chroococcidiopsis cf. cubana Komárek et Hindák

















Proposed Denitrifers


http://www.cyanodb.cz

Matteia

Matteia sp., a cyanobacterium found on desert rocks, has been proposed to dissolve carbonate rocks both for release of CO₂ and in hopes of creating a Martian carbon cycle.[6]

Psuedomonads and Alcaligenes

Psuedomonads and Alcaligenes could be appropriate denitrifiers once enough oxygen and carbonate are present to sustain them.[10]

Proposed GEMOs

Bacillus Polymyxa

A Facultative anaerobe that can form endospores, can fix nitrogen aerobically and anaerobically, and has tolerance to heavy metals. A good start for an eventual GEMO.[9]





A better GEMO may do the trick _{http://www.usc.edu/hsc/info/pr/hmm/04fall/superbug.html}














Current Research

There is no current research being done on terraforming.


References

[1]Birch, P. “Terraforming Mars Quickly” Journal of the British Interplanetary Society. 1992. Volume 45. p. 331-340

[2]Birch, P. “Terraforming Venus Quickly” Journal of the British Interplanetary Society. 1991. Volume 44. p. 157-167

[3]Blackhurst, R., Verchovsky, A., Jarvis, K., Grady, M.M. “Cryptoendolith communities in Antarctic Dry Valley Region Sanstones: Potential Analogues of Martian Life-Forms”
Lunar and Planetary Science. 2003. Volume 34.

[4]Farquhar, J., Bao, H., Thiemens, M. Atmospheric Influence of Earth’s Earliest Sulfur Cycle” Science. 2000. Volume 289. P. 756-758


[5]Fogg, M. J., "Terraforming" Society of Automotive Engineers. 1995. Warrendale, PA

[6]Friedmann, EI., Hua, M., Ocampo-Friedmann, R. “Terraforming Mars: dissolution of carbonate rocks by cyanobacteria” Journal of Interplanetary Society. 1993. Volume 46. P. 291-292
[7]Friedmann, EI., Ocampo-Friedmann, R. "A Primitive Cyanobacterium as Pioneer Microorganism for Terraforming Mars" Adv. Space Res. 1994. Volume 15, No. 3. p. 243-246

[8]Graham, J., Graham L. "Chapter 18: Terraforming Mars" 1989.

[9]Hiscox, J., Thomas, D. “Genetic Modification and Selection of Microorganisms for Growth on Mars” Journal of the British Interplanetary Society. 1995 Volume 48. P. 419-426.


[10]Thomas, D. “Biological Aspects of the Ecopoeisis and Terraformation of Mars: Current Perspectives and Research” Journal of the British Interplanetary Society. 1995. Volume 48. P. 415-418

[11]Sagan, C. "The Planet Venus" Science 1961. Volume 133. p. 849-858


[12]Seckbach, J., Baker, F.A., Shugarman, P.M. "Algae Thrive in Pure CO₂" Nature. 1977. Volume 227. p. 774-775




Edited by Samantha Chavez, a student of Angela Kent at the University of Illinois at Urbana-Champaign.