Preservation of Organic Biosignatures in Icelandic Iron Sinter Springs

Sean Burnette

Authors:  Sean Burnette

Faculty Mentor: Dr. Amy Williams

College:  College of Liberal Arts and Sciences


Relict hot springs on Mars present habitable environments where bacteria-like organisms could be preserved as biosignatures, if life arose on Mars. Silica sinter hot springs are common on Earth, observed on Mars, and known to preserve physical and molecular biosignatures. In contrast, iron oxides, which are ubiquitous on Mars, often degrade organic biosignatures. This work explores the detection of organic biosignatures in the Mars-analog acidic iron-sinter Kerlingerfjӧll and neutral Red Dragon Creek springs in Iceland, to assess the preservation of organic biosignatures in a mixed silica sinter and iron oxide spring system. Preservation of organic molecules and compounds associated with lipids is regarded as a biosignature, as all terrestrial life uses lipids in their cellular machinery. Rock samples were solvent washed to remove external organic contamination and analyzed using pyrolysis gas chromatography mass spectrometry (GC-MS). Samples were treated with trimethylsulfonium hydroxide to make organic fatty acids more volatile and detectable to GC-MS. Preliminary results show evidence of saturated fatty acids with unsaturations and iso- and anteiso-fatty acids preserved in the circumneutral spring. By exploring the effects of iron and sinter mineralogy on biosignature preservation in these samples, this work assesses whether similar Martian environments are prime locations for biosignature detection.

Poster Pitch

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13 Responses
  1. Amy Williams

    Great summary of your work Sean! This is an important step forward in understanding organic biosignature preservation in iron-bearing mineralogies and the impact they have on the search for biosignatures on Mars!

    1. Sean Burnette

      Thank you for the opportunity to work on this project! I learned a ton about geobiology and lab work in general!

  2. Samantha Ocon

    Hi Sean! I’m wondering how you became interested in astrobiology and geology. I am also a geology major with a specialty in paleobiology, and I have always been interested in the ways that others find their way into the geosciences.


    1. Sean Burnette

      Hey Sam,
      I started here at UF as an Astronomy major and realized that I was more interested in the geology side of planets as opposed to the physics aspect. Once I took Dr. Williams’ geobiology course I was really intrigued by the subject!

  3. Courtney Sprain

    Great work Sean! I was wondering if you have thought about looking for biosignatures that are not organic? For example, it has been suggested that some of the earliest forms of life on earth could have been magnetotactic bacteria, which grow chains of magnetic particles (Fe-oxides or Fe-sulfides) to help them with navigation. We often see these chains preserved in sediments and people suggest they could be used to identify ancient life. Is it possible these type of bacteria live in these springs, and that their chains of magnetic minerals could be preserved in the Fe-rich spring?

    1. Sean Burnette

      I believe that a previous undergraduate researcher did in fact look for non-organic biosignatures in these samples! If I remember correctly, the physical biosignatures were similarly lower in iron-rich samples compared to the more silica-rich samples. I’m not sure if magnetotactic biosignatures have been targeted in these samples specifically, however that sounds like a worthwhile study!

  4. Chance Sturrup

    Awesome job Sean! Very interesting that the circum-neutral spring has increased diversity with FAMEs, do they exhibit more FAMEs overall or simply a greater diversity within the limited amount detected?

    1. Sean Burnette

      Thanks, Chance.
      The circumneutral spring appears to have both greater diversity and more FAMEs overall!

  5. Hi Sean, this is a great presentation! I appreciate your comparison of two sites, and the conclusions you yielded about preferential pH tells us a lot about life’s limits. Thanks for sharing!

    1. Sean Burnette

      Thanks, Sydney! I agree that the conclusions about pH preference are interesting and I wasn’t really expecting that when I first began this project.

  6. Joe Meert


    Thanks for a nice poster/video presentation of your work. What future efforts do you think might prove useful and were there any parts of your research that were dead ends?

  7. Sean Burnette

    Thank you, Dr. Meert! I think that future efforts regarding the mineralogy of the individual samples would allow for more in depth results. I did have 4 samples with poor data that looked mostly like background noise which was disappointing. Luckily these were from the spring that was sampled 7 times and not the one that was sampled 3 times!

  8. Anthony Pivarunas

    Nice work, Sean! I was wondering what the timescale of preservation for these biosignatures is. Would they be preserved (and therefore detectable) from as far back as the Noachian on Mars?