Publications

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2008
Botta, O, Bada JL, Gomez-Elvira J, Javaux E, Selsis F, Summons R.  2008.  "Strategies of life detection": Summary and outlook. Space Science Reviews. 135:371-380.   10.1007/s11214-008-9357-9   Website
2007
Skelley, AM, Aubrey AD, Willis PA, Amashukeli X, Ehrenfreund P, Bada JL, Grunthaner FJ, Mathies RA.  2007.  Organic amine biomarker detection in the Yungay region of the Atacama Desert with the Urey instrument. Journal of Geophysical Research-Biogeosciences. 112   10.1029/2006jg000329   AbstractWebsite

The Urey in situ organic compound analysis instrument, consisting of a subcritical water extractor ( SCWE) and a portable microchip capillary electrophoresis instrument called the Mars Organic Analyzer ( MOA), was field tested in the Atacama Desert, Chile, in June 2005. Soil samples from the most arid Yungay region were collected, biomarkers were extracted by the SCWE, and organic amine composition and amino acid chirality analysis was performed by the MOA. Samples collected from the top 1 cm of duracrust soil but shielded from the ambient environment by rocks were compared to the exposed duracrust. The shielded duracrust yielded amines and amino acids ranging from 50 to 100 ppb, while amino acid signals from the exposed duracrust were below blank levels. Samples from buried gypsum deposits located directly above a water flow channel contained amino acids ranging from 13 to 90 ppb. Chiral analysis revealed D/L ratios of 0.39 +/- 0.08 and 0.34 +/- 0.07 for alanine/serine and 0.78 +/- 0.06 for aspartic acid, indicating significant racemization of biologically produced amino acids. On the basis of the D/L ratios, we estimate sample ages ranging from 10(3) to 10(5) years. These results demonstrate the successful field testing of the Urey instrument, as well as the detection of biomarkers from past terrestrial life in one of the most arid and Mars-like regions on Earth.

2001
Bada, JL.  2001.  State-of-the-art instruments for detecting extraterrestrial life. Proceedings of the National Academy of Sciences of the United States of America. 98:797-800.   10.1073/pnas.98.3.797   Website