Authors: Chance Sturrup, Amy Williams, Mary Rogers
Faculty Mentor: Dr. Amy Williams
College: College of Liberal Arts and Sciences
Discovering whether past or present life exists on Mars is one of the most gripping questions of modern astrobiology. The distance between Mars and Earth results in the need for specialized instruments to address this question on Mars missions. One such instrument utilizes pyrolysis gas chromatography mass spectrometry (pyro-GC-MS) to detect organic molecules preserved within the rock record. Both the NASA Curiosity and ESA ExoMars rovers have the ability to perform these experiments using their onboard instruments. These experiments can be simulated on Earth by using acid-saline Mars analog samples acquired from acid mine drainage (AMD) sites. By exploring the preservation of organic matter from extremophiles in AMD, we can explore organic molecule preservation in select acid-saline environments on Mars. The terrestrial site chosen for research was the Centralia AMD site in Pennsylvania, which serves as an effective analog for the Burns formation on Mars. These experiments target alkanes and fatty acids since they are important components of microbial cells. Preliminary data obtained from fatty acid analysis indicates that these molecules can be effectively detected in acid and neutral pH AMD with pyro-GC-MS, and ongoing research will explore the effect of pH and solvent washing of samples on organics preservation.
Nice presentation. I was curious as to how far back in time these methods are useful? For example, if life only existed on Mars 1 billion years ago, it seems unlikely that we can detect it with your methods? Is that right?
Thank you Dr. Meert!
As for your question, judging by the first wave of data it is difficult to determine just how long the residency time of these molecules can be. I plan to conduct further experiments with solvent washed samples to better understand the rate of decay of preserved FAMEs and Alkanes. At the moment I’d say that 1 billion years is likely too far back for this method to detect at least for Martian surface samples due to the large amount of radiation present.
Great presentation and poster, Chance! Your work really highlights the differences in hydrocarbon detection in these acidic and circumneutral sites, and the differences in the acidophilic and nuetrophilic iron-oxidizing organisms that are present in those environments.
Thank you very much Dr. Williams! I look forward to continuing the research to discover how detection of FAMEs and Alkanes in solvent-washed samples fairs in regards to their untreated counterparts.
Chance, very interesting work! I was wondering what the SAM instrument on Curiosity has found so far in regards to biosignatures, and what future plans are for the rover in that arena.
Thank you Anthony!
The SAM instrument itself has made some pretty impressive discoveries, it actually discovered trace organic molecules in 2018. However, these aren’t definitive bio signatures since the molecules it detected were too badly damaged by radiation to determine a biotic origin. The 2020 rover Perseverance is planned to focus a lot more on discovering past microbial communities, specifically those that might be preserved beneath the immediate surface.
Hi Chance, great presentation! Awesome work shedding light on varying pH may affect biomarker detection and applying this to Martian life detection. Do you think there is a way to control the detrital matter that contaminates the samples (such as in CMDS3)?
Thank you Sydney!
As for limiting the interference of detritall matter, I feel that future runs could utilize a solvent-wash method to remove any surface organics and contamination. Any samples run through the GC-MS afterwards would likely express lower FAME and alkane concentrations but those concentrations would be more representative of microbial communities.
Great work, Chance! I was wondering if there are any ancient examples of these types of environments on Earth where we could test for ancient records of organic biosignatures? Do you know of any geologic examples of environments in which extremophiles may have thrived?
Thank you very much!
As for ancient examples I cannot think of any right now, though modern day locations such as the Danakill Depression in Ethiopia indicate that past rift and volcanic environments likely hold the greatest potential for discovering Mars-like extremophiles. I will definitively be looking further into ancient deposits as I transition my research towards determining the time-table over which FAMEs and Alkanes can be preserved.
Nice professional presentation, Chance! I’m excited to see how the rest of your research pans out!
Thank you Sean!
Great poster, Chance! How did you find your way into Geobiology? I’m always interested in other geobiologists’ journeys.
Thank you Sam!
As for how I got into Geo biology I had initially gotten into geology with the aim of focusing on petrology. When Dr. Williams joined the department and put out a request for undergraduate researchers I reached out to her and joined her lab group. At the time I knew next to nothing about geobiology but over the next year and a half of working in her lab I developed an understanding and a passion for the subject as a whole! The fact that I get to work with Mars analogs and other forms of planetary science (a dream of mine since I was a kid) along with my studies of geobiology is pretty much a dream come true for me.
Thank you Sam!
As for how I got into geobiology, it really started when I applied to join Dr. Amy Williams lab group as an undergraduate researcher. At the time I knew next to nothing about geobiology but the last year and half of working as a part of her lab as given me an understanding and a passion for the subject!
Awesome research, Chance! Being able to detect extremophile life on Mars is invaluable if life there developed similarly to on Earth. It’s incredible how so many aspects of the biochemical framework developed in early Domain Archaea have been retained in modern Archaeans and even in modern eukaryotes. It would be fascinating to be able to compare the development of life between Earth and Mars in such early stages! I have a question though: is there a significant trend in alkane length between CMPD1 and CMPD5, and if so, what would it imply?
My bad, a little confused with the platform!
Awesome research, Chance! Being able to detect extremophile life on Mars is invaluable if life there developed similarly to on Earth. It’s incredible how so many aspects of the biochemical framework developed in early Domain Archaea have been retained in modern Archaeans and even in modern eukaryotes. It would be fascinating to be able to compare the development of life between Earth and Mars in such early stages! I have a question though: is there a significant trend in alkane length between CMDS1 and CMDS3 and if so, what would it imply?