Raman spectroscopy is being adopted as a nondestructive instrumentation for the robotic exploration of Mars to search for traces of life in the geological record. Here, miniaturized Raman spectrometers of two different types equipped with 532 and 785 nm lasers for excitation, respectively, were compared for the detection of microbial biomarkers in natural halite from the hyperarid region of the Atacama Desert. Measurements were performed directly on the rock as well as on the homogenized, powdered samples prepared from this material-the effects of this sample preparation and the excitation wavelength employed in the analysis are compared and discussed. From these results, 532 nm excitation was found to be superior for the analysis of powdered specimens due to its high sensitivity toward carotenoids and hence a higher capability for their detection at relatively low concentration in bulk powdered specimens. For the same reason, this wavelength was a better choice for the detection of carotenoids in direct measurements made on the rock samples. The 785 nm excitation wavelength, in contrast, proved to be more sensitive toward the detection of scytonemin.

Institute of Geochemistry Mineralogy and Mineral Resources Charles University Prague 128 43 Prague 2 Czech Republic

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de los Ríos A. Valea S. Ascaso C. Davila A. Kaštovský J. McKay C.P. Gómez-Silva B. Wierzchos J. Comparative analysis of the microbial communities inhabiting halite evaporites of the Atacama Desert. Int Microbiol. 2010;13:79–89. PubMed

Dickensheets D.L. Wynn-Williams D.D. Edwards H.G.M. Schoen C. Crowder C. Newton E.M. A novel miniature confocal microscope/Raman spectrometer system for biomolecular analysis on future Mars missions after Antarctic trials. J Raman Spectrosc. 2000;31:633–635.

Edwards H.G.M. Garcia-Pichel F. Newton E.M. Wynn-Williams D.D. Vibrational Raman spectroscopic study of scytonemin, the UV-protective cyanobacterial pigment. Spectrochim Acta A Mol Biomol Spectrosc. 2000;56:193–200. PubMed

Edwards H.G.M. Moody C.D. Villar S.E.J. Wynn-Williams D.D. Raman spectroscopic detection of key biomarkers of cyanobacteria and lichen symbiosis in extreme Antarctic habitats: evaluation for Mars lander missions. Icarus. 2005;174:560–571.

Fendrihan S. Musso M. Stan-Lotter H. Raman spectroscopy as a potential method for the detection of extremely halophilic archaea embedded in halite in terrestrial and possibly extraterrestrial samples. J Raman Spectrosc. 2009;40:1996–2003. PubMed PMC

Jehlička J. Vítek P. Edwards H.G.M. Raman spectra of organic acids obtained using a portable instrument at −5°C in a mountain area at 2000 m above sea level. J Raman Spectrosc. 2009;41:440–444.

Marshall C.P. Carter E.A. Leuko S. Javaux E.J. Vibrational spectroscopy of extant and fossil microbes: relevance for the astrobiological exploration of Mars. Vib Spectrosc. 2006;41:182–189.

Marshall C.P. Leuko S. Coyle C.M. Walter M.R. Burns B.P. Neilan B.A. Carotenoid analysis of halophilic archaea by resonance Raman spectroscopy. Astrobiology. 2007;7:631–643. PubMed

McKay C.P. Friedmann E.I. Gómez-Silva B. Cáceres-Villanueva L. Andersen D.T. Temperature and moisture conditions for life in the extreme arid region of the Atacama Desert: four years of observations including the El Niño of 1997–1998. Astrobiology. 2003;3:393–406. PubMed

Merlin J.C. Resonance Raman spectroscopy of carotenoids and carotenoid-containing systems. Pure Appl Chem. 1985;57:785–792.

Russell N.C. Edwards H.G.M. Wynn-Williams D.D. FT-Raman spectroscopic analysis of endolithic microbial communities from Beacon sandstone in Victoria Land, Antarctica. Antarct Sci. 1998;10:63–74.

Vandenabeele P. Jehlička J. Vítek P. Edwards H.G.M. On the Raman spectroscopic detection limits for the analysis of biomarkers in solid matrices. Planet Space Sci. 2012;62:48–54.

Villar S.E.J. Edwards H.G.M. Cockell C.S. Raman spectroscopy of endoliths from Antarctic cold desert environments. Analyst. 2005;130:156–162. PubMed

Vítek P. Jehlička J. Edwards H.G.M. Osterrothová K. Identification of β-carotene in an evaporitic matrix—evaluation of Raman spectroscopic analysis for astrobiological research on Mars. Anal Bioanal Chem. 2009;393:1967–1975. PubMed

Vítek P. Edwards H.G.M. Jehlička J. Ascaso C. de los Ríos A. Valea S. Villar S.E.J. Davila A.F. Wierzchos J. Microbial colonization of halite from the hyper-arid Atacama Desert studied by Raman spectroscopy. Philos Transact A Math Phys Eng Sci. 2010;368:3205–3221. PubMed

Vítek P. Ali E.M.A. Edwards H.G.M. Jehlička J. Cox R. Page K. Evaluation of portable Raman spectrometer with 1064 nm excitation for geological and forensic applications. Spectrochim Acta A Mol Biomol Spectrosc. 2012;86:320–327. PubMed

Wierzchos J. Ascaso C. McKay C.P. Endolithic cyanobacteria in halite rocks from the hyperarid core of the Atacama Desert. Astrobiology. 2006;6:415–422. PubMed

Wynn-Williams D.D. Edwards H.G.M. Proximal analysis of regolith habitats and protective biomolecules in situ by laser Raman spectroscopy: overview of terrestrial Antarctic habitats and Mars analogs. Icarus. 2000a;144:486–503.

Wynn-Williams D.D. Edwards H.G.M. Antarctic ecosystems as models for extraterrestrial surface habitats. Planet Space Sci. 2000b;48:1065–1075.

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