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Science 1 October 1976:
Vol. 194. no. 4260, pp. 99 - 105
DOI: 10.1126/science.194.4260.99
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Articles

The Viking Biological Investigation: Preliminary Results

HAROLD P. KLEIN 1, NORMAN H. HOROWITZ 2, GILBERT V. LEVIN 3, VANCE I. OYAMA 4, JOSHUA LEDERBERG 5, ALEXANDER RICH 6, JERRY S. HUBBARD 7, GEORGE L. HOBBY 8, PATRICIA A. STRAAT 9, BONNIE J. BERDAHL 4, GLENN C. CARLE 4, FREDERICK S. BROWN 10, and RICHARD D. JOHNSON 4

1 NASA Ames Research Center, Moffett Field, California 94035
2 Division of Biology, California Institute of Technology, Pasadena 91125
3 Biospherics Incorporated, Rockville, Maryland 20852
4 NASA Ames Research Center
5 Department of Genetics, Stanford University, Stanford, California 94305
6 Department of Biology, Massachusetts Institute of Technology, Cambridge 02139
7 Department of Biology, Georgia Institute of Technology, Atlanta 30332
8 Department of Biology, California Institute of Technology
9 Biospherics Incorporated
10 TRW Systems, One Space Park, Redondo Beach, California 90278

Three different types of biological experiments on samples of martian surface material ("soil") were conducted inside the Viking lander. In the carbon assimilation or pyrolytic release experiment, 14CO2 and 14CO were exposed to soil in the presence of light. A small amount of gas was found to be converted into organic material. Heat treatment of a duplicate sample prevented such conversion. In the gas exchange experiment, soil was first humidified (exposed to water vapor) for 6 sols and then wet with a complex aqueous solution of metabolites. The gas above the soil was monitored by gas chromatography. A substantial amount of O2 was detected in the first chromatogram taken 2.8 hours after humidification. Subsequent analyses revealed that significant increases in CO2 and only small changes in N2 had also occurred. In the labeled release experiment, soil was moistened with a solution containing several 14C-labeled organic compounds. A substantial evolution of radioactive gas was registered but did not occur with a duplicate heat-treated sample. Alternative chemical and biological interpretations are possible for these preliminary data. The experiments are still in process, and these results so far do not allow a decision regarding the existence of life on the plonet Mars.

Submitted on September 6, 1976


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
On the ability of the Viking gas chromatograph-mass spectrometer to detect organic matter.
K. Biemann (2007)
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The limitations on organic detection in Mars-like soils by thermal volatilization-gas chromatography-MS and their implications for the Viking results.
R. Navarro-Gonzalez, K. F. Navarro, J. d. l. Rosa, E. Iniguez, P. Molina, L. D. Miranda, P. Morales, E. Cienfuegos, P. Coll, F. Raulin, et al. (2006)
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Evidence That the Reactivity of the Martian Soil Is Due to Superoxide Ions.
A. S. Yen, S. S. Kim, M. H. Hecht, M. S. Frant, and B. Murray (2000)
Science 289, 1909-1912
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Possible Surface Reactions on Mars: Implications for Viking Biology Results.
C. Ponnamperuma, C. PONNAMPERUMA, A. SHIMOYAMA, M. YAMADA, T. HOBO, and R. PAL (1977)
Science 197, 455-457
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Scientific Results of the Viking Missions.
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Science 194, 1274-1276
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The Viking Carbon Assimilation Experiments: Interim Report.
N. H. Horowitz, N. H. HOROWITZ, G. L. HOBBY, and J. S. HUBBARD (1976)
Science 194, 1321-1322
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Viking Labeled Release Biology Experiment: Interim Results.
G. V. Levin, G. V. LEVIN, and P. A. STRAAT (1976)
Science 194, 1322-1329
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Status of the Viking Missions.
G. A. Soffen and G. A. SOFFEN (1976)
Science 194, 57-59
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Search for Organic and Volatile Inorganic Compounds in Two Surface Samples from the Chryse Planitia Region of Mars.
K. Biemann, K. BIEMANN, J. ORO, P. TOULMIN III, L. E. ORGEL, A. O. NIER, D. M. ANDERSON, P. G. SIMMONDS, D. FLORY, A. V. DIAZ, et al. (1976)
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Preliminary Results from the Viking X-ray Fluorescence Experiment: The First Sample from Chryse Planitia, Mars.
P. Toulmin, P. TOULMIN III, B. C. CLARK, A. K. BAIRD, K. KEIL, and H. J. ROSE JR. (1976)
Science 194, 81-84
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