In the Lab
Author: Allyson Edwards | Major: Biochemistry | Semester: Fall 2023
Life on other planetary bodies is a topic that’s been of interest to the scientific community and public for years now. The potential of life on Mars is something I’ve been researching under my mentor, Dr. Timothy Kral, over the course of the semester. Dr. Kral’s lab investigates the possibility of microorganisms living within the subsurface of Mars. These organisms are called methanogens, and by studying their growth in simulated Martian conditions, we can draw some interesting conclusions regarding the possibility of life on Mars.
The Mars Express spacecraft has detected methane in Mars’ atmosphere, leading us to question where this methane came from. There are a few ideas including both biogenic and nonbiogenic sources, but the Kral laboratory focuses on studying four specific methanogens: Methanothermobacter wolfeii, Methanobacterium formicicum, Methanosarcina barkeri, and Methanococcus maripaludis. Methanogens are anaerobic microorganisms that utilize inorganic chemical energy to grow rather than light energy. Methane is released as a result of their metabolism, and as extremophiles, they’re regarded as some of the most primitive organisms on Earth.
Organisms that are extremophiles can more easily grow in areas with limited energy sources. Methanogens are quite simple, requiring carbon dioxide, water, and molecular hydrogen as main energy sources to grow. All of these compounds can potentially be found in the Martian subsurface. It’s also important to note that the surface conditions of Mars are very harsh. These two facts combine to make a strong case for the possibility of methanogens existing beneath the surface of the planet.
Dr. Kral’s laboratory has previously demonstrated that, if provided with the proper nutrients, these methanogens are able to survive on a Mars soil simulant. The different organisms require slightly different growth media, but they all contain four base solutions. These solutions, labeled A, B, C, and D, are understood to be a requirement to grow these organisms. My project centers around attempting to grow the organisms without one of the solutions present: Solution D.
Solution D contains 12 different minerals and is considered a trace mineral solution. My project observes the difference in growth between the control media and the media lacking solution D. The goal is to investigate the possibility of growing the organisms without the trace mineral solution present. My results thus far have shown growth for M. wolfeii, M. formicicum, and M. barkeri, but not M. maripaludis by using a gas chromatograph to measure the methane levels over time. Growth of these organisms in stricter media may have significance in drawing parallels to the harsh conditions of Mars. For example, the trace minerals contained in Solution D may not be present in large amounts in the Martian subsurface. These results open the door for other questions to be asked.
Methanogen survival in extreme experimental conditions provides support for the idea that they may survive in extreme environmental conditions on Mars. I’m currently beginning to investigate whether these methanogens can grow on the same, most basic medium rather than their individual media. Solution D will be reintroduced during this experiment, but this could be further simplified in the future if results are promising. The Honors College Research Grant allowed me to conduct this research, as well as grow and expand my ideas for future alterations to my project. I’m very grateful to for the opportunity to conduct research that is so relevant in society.