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Science 11 September 1981:
Vol. 213. no. 4513, pp. 1245 - 1247
DOI: 10.1126/science.213.4513.1245
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Articles

Microbial Origin of Desert Varnish

R. I. DORN 1 and T. M. OBERLANDER 1

1 Department of Geography, University of California, Berkeley 94720

Scanning electron microscopy and energy dispersive x-ray analyses of desert varnish reveal that microorganisms concentrate ambient manganese that becomes greatly enhanced in brown to black varnish. Specific characteristics of desert varnish and of varnish bacteria support a microbial origin for manganese-rich films. Varnish microbes can be cultured and produce laboratory manganese films. Accordingly, natural desert varnish and also manganese-rich rock varnishes in nondesert environments appear to be a product of microbial activity.

Submitted on May 19, 1981


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
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High-resolution analysis of silica and sulphate-rich rock varnishes from Victoria Land (Antarctica).
G. Giorgetti and C. Baroni (2007)
European Journal of Mineralogy 19, 381-389
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Baking black opal in the desert sun: The importance of silica in desert varnish.
R. S. Perry, B. Y. Lynne, M. A. Sephton, V. M. Kolb, C. C. Perry, and J. T. Staley (2006)
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Diversity of Microorganisms within Rock Varnish in the Whipple Mountains, California.
K. R. Kuhlman, W. G. Fusco, M. T. La Duc, L. B. Allenbach, C. L. Ball, G. M. Kuhlman, R. C. Anderson, I. K. Erickson, T. Stuecker, J. Benardini, et al. (2006)
Appl. Envir. Microbiol. 72, 1708-1715
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Structural characterization of biogenic Mn oxides produced in seawater by the marine bacillus sp. strain SG-1.
S.M. Webb, B.M. Tebo, and J.R. Bargar (2005)
American Mineralogist 90, 1342-1357
   Abstract »    Full Text »    PDF »
Characterization of manganese oxide mineralogy in rock varnish and dendrites using X-ray absorption spectroscopy.
D. A. McKeown and J. E. Post (2001)
American Mineralogist 86, 701-713
   Abstract »    Full Text »    PDF »
Stable Carbon Isotope Ratios of Rock Varnish Organic Matter: A New Paleoenvironmental Indicator.
R. I. Dorn, R. I. DORN, and M. J. DENIRO (1985)
Science 227, 1472-1474
   Abstract »    PDF »
Weathering.
W. B. Whalley, W.B. Whalley, and J.P. McGreevy (1983)
Progress in Physical Geography 7, 559-586
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Rock varnish.
R. I. Dorn and T. M. Oberlander (1982)
Progress in Physical Geography 6, 317-367
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