Authors: Sydney Shaner, Amy Williams, Guangsheng Zhuang
Faculty Mentor: Dr. Amy Williams
College: College of Liberal Arts and Sciences
Analog sites on Earth provide us with settings to test astrobiological techniques in pursuit of life on other worlds. In this study, the focus is Qaidam Basin located in China, a hyperarid analog for Gale Crater, Mars. Because of the hyperaridity of Qaidam Basin, complex molecules such as lipids that would be indicative of fossilized life have high preservation potential. We use flash pyrolysis, trimethylsulfonium hydroxide (TMSH) injection, and gas chromatography-mass spectrometry to analyze clays for their organics composition and preservation. With C19 as a standard, alkanes C4 – C26 and the alkene C12:1 were produced by flash pyrolysis. With the addition of C19 and TMSH standards, the fatty acid methyl esters C4, C5, C6, C7¬, C8, C9, C10, C11, C12, C14, and C18¬ were produced by flash pyrolysis. We report that this method of analyzing organics preservation is fruitful in a Mars analog and can be applied to the in situ analysis done by the NASA Sample Analysis at Mars instrument suite aboard the Curiosity rover in future missions to detect possible life.
Sydney,
Nice job on your work. Suppose that life on Mars no longer exists, but may have been around a billion years ago. Would your methods work? If not, how far back is your methodology useful?
Hi Joe,
While still present, our older samples (Eocene) have a lesser abundance of lipid biomarkers detected by flash pyro GC-MS. I would imagine that this method would likely not be useful for samples orders of magnitude older. Perhaps injecting TMSH to liberate the biosignatures can still be applied to other methods, as it was fruitful here. Thanks for your question!
Great poster and presentation Sydney!
Great poster and presentation, Sydney! Your results are so intriguing for the Eocene vs last glacial max. The lack of wax esters in the Eocene samples does make me wonder if our space-flight-like whole sample procedure is limiting our detection, as wax esters should stick around in arid environments for a long time. Any leads on what the C24 spike in the Eocene sample alkanes represents? Other than higher plants (so we know they had to be there!).
Hi Amy, C24 is also found in animal muscles, although higher plants is the more likely/populous contributor. I’m sure more work could be done to look into the paleoevironment, paleoecology, and lacustrine evolution of Qaidam Basin in conjunction with biosignature studies to paint a picture of what a hyperarid environment used to look like and what could have lived there to produce these biosignatures. Thanks for your guidance with this fascinating research!
Great job on the presentation Sydney! You presented your information in a clear and engaging way and I am very excited to see where your research continues. I was wondering how far back the method can be used to detect microbial bio-signatures? Is the data currently limited to modern communities or can past ones be seen as well?
Hi Chance! Thanks so much for your comment. The older set of samples are of Eocene age and yielded a lesser abundance of FAMEs than last glacial max samples, meaning there is already a significant degradation over thousands of years. As pointed out in a previous comment, it likely would not be appropriate for orders of magnitude older. I think TMSH could still be utilized on SAM, though, as these experiments showed that method’s potential!
Great bob Sydney! I was wondering, along the vein of Joe’s question, how the organic biosignatures break down with time. Which ones seem to be more stable to and why?
Hi Courtney, thank you for your comment. Lipid biosignatures have been investigated in other studies as being resistant to microbial degradation and being able to survive even in iron oxides; they are looked into as one of the main biomarkers for life for this reason. Also, they are used in our research and others because they can be manipulated (such as liberation) and do tell not only that life existed, but potentially what kind based on their structural character. I think it would be worthwhile to do more comparative studies between lipid biosignatures such as these and other molecules, with regards to degradation time instead of what yields more detailed results.
Great job, Sydney! I’m so proud of you.
How did you find your love of geology and astrobiology?
Sam
Thank you so much, Sam! I have always had a love for the kinds of mysteries life presents down to the finer details–what are the limits for life and where did it begin? If we know the limits and can find a place that exhibits characters right at the limit, would we find life (i.e. Martian life)? I’d love to continue answering these questions in my career!
Sydney!
You look great and your poster is beautiful! I wanted to ask what a yarding is? Maybe I’m not typing it correctly but you say it at about :37 in your video.
Hi Claudia! Thank you! A yardang is an aeolian feature (like a small, densely packed ridge) formed from lesser densely packed material being blown away. These are found on Mars and at Qaidam Basin.
Excellent work, Sydney! That biomolecules could be preserved for so long in hyperarid settings opens up a lot of opportunities to conduct comparitive studies of modern and ancient microbial life here on Earth and on Mars! For your study, you looked at lipids and measuring their fatty acid component signatures, could this methodology be used to detect amino acid or nucleic acid signatures? Or is the environment specifically suited to preserving lipids?
Thanks David! I’m not familiar as to whether or not this method can be extrapolated on our specific instruments. However, I think comparative studies for preservation potential should be done for various biomarkers in the future. Qaidam Basin likely has the potential to contain all sorts of biomarkers as it was previously a lake habitat!
Nice work, Sydney. What do you think of the possibility that life exists on Mars currently?
Thank you, Tony. While I think astrobiological life does exist, we’re likely limited to the remnants of it on Mars.
Great work on your poster, Sydney! It does a really nice job of displaying the information and I especially like the formatting of your graphs!
Great job girl! Now, if you were taking the next step in your research, what would analytical tool would you like to use and why?