Creating a New Earth: Terraforming the Martian Atmosphere with Microbes

Jennifer Baily
Thomas Jefferson High School for Science and Technology

Ever since the dawn of the human race, the heavens have enthralled us- despite their irrelevance to the daily happenings on the Earth.  Just like everyone else who stared at the night sky, I too fell prey to that captivation. Over the past few thousand years, the human species has progressed from merely viewing the stars through crude telescopes to setting foot on the moon. The next step in humanity’s path through the heavens is Mars. Despite its relative safety, Mars will almost instantly kill anyone who sets foot on the surface. When I’m in the Astronomy lab, my partner and I are tackling this issue by drawing up design after design of a device capable of using microbes to make the Martian atmosphere breathable.

The idea that we could have astronauts on or orbiting Mars within our lifetime seems almost like a fever dream in its outlandishness, but it’s not one at all. The National Aeronautics and Space Administration (NASA) has released its plan for sending astronauts to Mars within the next thirty years two years ago (2015). However, their plan doesn’t discuss the putting astronauts on Mars permanently or semi-permanently for many unspoken reasons. Mars is inherently inhospitable to human life- what with its low pressures, freezing temperatures, and conspicuous lack of a substantial atmosphere among other things. One of the most notable issues with putting people on Mars is the makeup of Mars’s atmosphere, and that is where my partner and I come in.

Have you ever stopped and thought about what exactly it is that you’re breathing in? The Earth’s atmosphere is 78% nitrogen gas, 21% oxygen gas, 0.9% argon, and 0.32% carbon dioxide, which is actually a really nice mixture to be walking around in on a day-to-day basis. There’s enough oxygen and carbon dioxide for photosynthesis and respiration, but not enough oxygen for everything to spontaneously ignite and not enough carbon dioxide to poison you- yes, too much carbon dioxide can kill you all by itself. Argon is a noble gas, so it doesn’t do much other than just sit there, and nitrogen gas provides a rich resource pool for helpful microbes called nitrogen fixers to convert into nitrate, one of the most important nutrients for plant growth. We often take this atmospheric constitution for granted, something you cannot do Mars’s atmosphere.

In comparison, the toxic stew we call the Martian atmosphere will kill you in minutes. First, you would asphyxiate from a lack of oxygen. If you miraculously survived without oxygen for more than a few minutes, the high concentrations of carbon monoxide and carbon dioxide would compete to kill you by poisoning your blood and shorting out your lungs. Even supposing you could withstand those toxins, the perchlorate dust would eventually damage your DNA, kick-starting the growth of cancer in you body. Clearly, purifying Mars’s atmosphere is a top priority for any terraforming project.

Although converting any significant portion of an inhospitable atmosphere into breathable material appears to be an insurmountable task, microbes managed to do it at a planetary level on our very own Earth. Approximately 2.2 billion years ago, our atmosphere contained mostly methane and carbon dioxide [3]. Then, a new type of bacteria called cyanobacteria evolved and transformed the atmosphere through a radical new chemical process called photosynthesis, which used the large reservoir of atmospheric carbon dioxide to generate energy and oxygen, which other organisms began to take advantage of soon after. This cataclysmic reimagining of Earth’s atmosphere is called The Great Oxygenation Event- and we hope to recreate it on a smaller scale in a filtration device for usage on Mars.

Although not much research exists specifically on this subject, many independent researchers around the world have conducted research relevant to the use of microbes to convert hazardous substances into neutral or beneficial products. In order to study the possibility of life on ancient Mars, a scientist at the University of Honolulu collected a variety of carbon monoxide oxidizing microbes, which turn carbon monoxide into carbon dioxide, and subjected them to Mars-like conditions [3]. One of those bacteria, Alkalilimnicola ehrlichii, proved to be an industrious carbon-monoxide-to-carbon-dioxide converter under both Earth and Mars conditions, making it uniquely suited for our project. Another study showed cyanobacteria operate well under ridiculously high concentrations of carbon dioxide, knocking out both the overabundance of carbon dioxide and the lack of oxygen from the list of hazards [7]. To finish with the gaseous portion of the problem, NASA scientists recently discovered nitrates in Martian rocks, which can be converted into nitrogen gas by a laboratory strain of Escherichia coli bacteria [6].

Unfortunately, perchlorate dust throws a few wrenches into the works, with the bacteria that can process it being hard culture and extremely expensive to obtain [8]. Additionally, a team of researchers has recently discovered perchlorates tend to release heavy metals from the soils they reside in and the extent to which this process occurs depends heavily on the environmental factors [4]. As my scientist correspondent, Meththika Vithanage, noted, the presence of perchlorates greatly increases the difficultly of detoxifying contaminated soil (Vithanage, personal communication, Jan. 11, 2017). There is very little research concerning the presence of heavy metals in Martian soil, making deciding how to deal with it a moot point. However, perchlorate can be removed from water with a simple chemical reaction, harvested, and even turned into rocket fuel [1].

After several years of little serious discussion on a Mars mission, the possibility of a manned Mars mission has suddenly become a reality. In September of 2016, Elon Musk, the CEO of SpaceX, announced his company’s plans to design and build their Interplanetary Transport System, which would permit 100 people to go on a round trip to Mars and facilitate colonization [9]. Moreover, President Trump recently met with Musk to discuss the future of astronauts on Mars, hopefully bringing us one step closer to making that dream a reality [2]. Given this increased attention on Mars, laying the groundwork for future expeditions, be they transitory or permanent, is essential for progress.

I believe humanity will reach Mars’s surface within the next hundred years. To realize that, advancements will need to arise in the field of life support technology to combat the wide array of dangers Mars holds for humans. Chief among those threats is the toxic composition of Mars’s atmosphere, which is why I and my partner have decided to study it, even if we have to kill a few trees with our frequent drawing up and scrapping of prototype designs.

References

[1] Davila, A. F., Wilson, D., Coates, J. D., & McKay, C. P. (2013). Perchlorate on Mars: a chemical hazard and a resource for humans. International Journal of Astrobiology, 12(4), 1-5. http://dx.doi.org/10.1017/S1473550413000189

[2] "Destination Mars" --Elon Musk and Trump partnership may signal NASA shift: "Human's a multi-planet species". (2017, January 23). The Daily Galaxy. Retrieved from http://www.dailygalaxy.com/my_weblog/2017/01/destination-mars-elon-musk-and-trump-partnership-signal-nasa-shift-humans-a-multi-planet-species.html

[3] King, G. M. (2015). Carbon monoxide as a metabolic energy source for extremely halophilic microbes: Implications for microbial activity in mars regolith. PNAS, 112(14), pp. 4465-4470. http://dx.doi.org/10.1073/pnas.1424989112

[4] Kumarathilaka, P., Oze, C., & Vithanage, M. (2016). Perchlorate mobilization of metals in serpentine soils. Applied Geochemistry, 74, 203-209. http://dx.doi.org/10.1016/j.apgeochem.2016.10.009

[5] NASA. (2015, October). Journey to Mars: Pioneering next steps in space exploration. Retrieved from http://www.nasa.gov/sites/default/files/atoms/files/journey-to-mars-next-steps-20151008_508.pdf

[6] Neal-Jones, N., & Steigerwald, W. (2015, March 24). NASA's curiosity rover finds biologically useful nitrogen on mars. Retrieved October 4, 2016, from http://www.nasa.gov/content/goddard/mars-nitrogen

[7] Ono, E., & Cuello, J. L. (2007). Carbon dioxide mitigation using thermophilic cyanobacteria. Biosystems Engineering, 96(1), 129-134. http://dx.doi.org/10.1016/j.biosystemseng.2006.09.010

[8] Ontiveros-Valencia, A., Tang, Y., Krajmalnik-Brown, R., & Rittman, B. (2014). Managing the interactions between sulfate- and perchlorate-reducing bacteria when using hydrogen-fed biofilms to treat a groundwater with a high perchlorate concentration. Water Research, 55, 215-224. http://dx.doi.org/10.1016/j.watres.2014.02.020

[9] Wall, M. (2016, September 27). SpaceX's Elon Musk unveils interplanetary spaceship to colonize Mars. Space.com. Retrieved from http://www.space.com/34210-elon-musk-unveils-spacex-mars-colony-ship.html