Conducting Research
Author: Allyson Edwards | Major: Biochemistry | Semester: Spring 2023
Over the course of the spring 2023 semester, I’ve been conducting research regarding life on Mars under my mentor, Dr. Timothy Kral. Both the scientific community and the general public have both been interested in life on other planetary bodies for years, with Mars in particular being a large point of discussion. Dr. Kral’s lab doesn’t exactly research aliens like you’d see in movies, but we do investigate the possibility of microorganisms existing within the subsurface of Mars. We do this by studying methanogen growth in simulated Martian conditions.
Methanogens are anaerobic microorganisms that utilize inorganic chemical energy as opposed to light energy. They are regarded as some of the most primitive microorganisms on Earth, and through their metabolism, they produce methane. We’re particularly interested in methanogens because methane was detected in the atmosphere of Mars by the Mars Express spacecraft—a discovery that poses a great question: where did the methane come from? There are a few prevalent candidates 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.
Because these microorganisms are extremophiles, they can more easily grow in areas with limited energy sources. They require water, carbon dioxide as a carbon source, and molecular hydrogen as an energy source—all of which are possible compounds found within the subsurface of Mars. This combined with knowledge of harsh surface conditions on the planet makes a strong case for the possibility of methanogens existing within a Martian subsurface environment.
Within Dr. Kral’s laboratory, it has been demonstrated that the select methanogens are able to survive on a Mars soil simulant if supplied with the proper nutrients. Typical growth media varies slightly between organisms, but they all contain four solutions within them: solutions A, B, C, and D. These solution components remain the same across all four types of growth media, as it has been understood that all four are needed to grow these organisms. My project revolves around trying to grow the organisms without one of these solutions.
Solution D is a trace mineral solution that contains 12 different minerals. In my project, the methanogens are grown on control media (normal growth media) and experimental media (media that contains all usual components except Solution D). This far into my project, I have had success in growing M. wolfeii, M. formicicum, and M. barkeri, but not M. maripaludis. Growth is measured by observing methane levels using a gas chromatograph. The successful growth of these organisms lacking Solution D may be significant, as the minerals within the solution may not be found in high supply in the subsurface of Mars. Overall, my results are very exciting as they open doors for other questions to be asked.
Because Mars is such an extreme environment, the more extreme I can make my experimental conditions, the more likely it may be for methanogens to be residing in the Martian subsurface. Over the summer and fall semesters I plan to attempt growing these organisms in even further simplified media. I will be doing this by trying to grow all the organisms in the simplest of all four growth media types lacking Solution D.
The Honors College Research Grant allowed me to conduct this research and expand my project’s horizons. I am grateful for the opportunity to research something that feels so prevalent in today’s scientific community, and I truly enjoy going into the lab and feeling accomplished when I leave.