Spectral Characterization of Pterin Molecules: Implications for Detecting Life on Mars
Abstract
The surface of modern Mars contains high concentrations of oxidized iron. On Earth, iron oxidation is a common microbial metabolism. If microbes lived on Mars, iron oxidation is a likely metabolism for those organisms. The search for iron-oxidizing bacteria (FeOB) on Mars involves the identification of molecular biosignatures. Molecular biosignatures are signs of past or present life based on the presence of molecules that formed from biologic processes. A molecular biosignature potentially unique to FeOB was detected in a variety of terrestrial samples of or related to FeOB using trimethylsulfonium hydroxide (TMSH) pyrolysis gas chromatograph mass spectrometry (py-GC-MS). This molecular biosignature is likely that of a pterin-bearing molecule. If the same pterin-bearing molecule is found in both active FeOB and older iron oxyhydroxide rock, this molecule may serve as an indicator that those rocks formed by FeOB metabolic processes. By extension, the discovery of this molecule in Martian rock may indicate that FeOB were once present on Mars. The reliable detection of this molecule may provide a new avenue to identify FeOB activity in iron-dominated environments on Earth and Mars. A library of reference spectra for pterin-bearing molecules reacted with TMSH was created to further characterize the pterin-bearing molecules detected by TMSH py-GC-MS in the terrestrial samples. The spectral characteristics of several pterin-related standards were analyzed using infrared, ultraviolet-visible, fluorescence, and proton nuclear magnetic resonance spectroscopy. These results will be compared to the spectra of the pterin-bearing molecules extracted from the terrestrial samples.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P31H3816C
- Keywords:
-
- 5464 Remote sensing;
- PLANETARY SCIENCES: SOLID SURFACE PLANETSDE: 5470 Surface materials and properties;
- PLANETARY SCIENCES: SOLID SURFACE PLANETSDE: 5494 Instruments and techniques;
- PLANETARY SCIENCES: SOLID SURFACE PLANETSDE: 5499 General or miscellaneous;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS