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Ultraviolet radiation-induced limitation to epilithic microbial growth in arid deserts – Dosimetric experiments in the hyperarid core of the Atacama Desert

Cockell, Charles S. and McKay, Christopher P. and Warren-Rhodes, Kim and Horneck, Gerda (2008) Ultraviolet radiation-induced limitation to epilithic microbial growth in arid deserts – Dosimetric experiments in the hyperarid core of the Atacama Desert. Journal of Photochemistry and Photobiology (B: Biology), 90, pp. 79-87. Elsevier. DOI: doi:10.1016/j.jphotobiol.2007.11.009.

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Abstract

Experiments were conducted during November 2003 in the dry core of the Atacama Desert, Yungay, Chile to test the hypothesis that UV radiation, in environments where liquid water is not available, and thus enzymatic repair of UV-induced damage is inhibited, can prevent epilithic colonization. Novel dosimeters made from the cryptoendolithic, desiccation and radiation-resistant cyanobacterium Chroococcidiopsis sp. isolated from the dry Negev desert, Israel, showed that monolayers of this organism were killed within one day. The diurnal profile of microbial loss of viability was investigated with dosimeters of Bacillus subtilis, which similarly showed cell death within one day. Soil grains obtained from south of Yungay where liquid water is more abundant and transported to the hyperarid core showed killing of indigenous vegetative organisms within one day. Gypsum and mineral grain coverings of 1 mm were sufficient to prevent measurable UV-induced damage of Chroococcidiopsis and B. subtilis after 8 d exposure. These results show that under extreme desiccation and an ambient UV flux the surface of rocks can potentially be rendered sterile, but that millimetre thick mineral coverings can protect organisms from UV-induced killing, consistent with the observed patterns of lithophytic colonization in the Atacama Desert. These data further show that UV radiation can be an important limiting factor in surface biological rock weathering in arid regions.

Document Type:Article
Title:Ultraviolet radiation-induced limitation to epilithic microbial growth in arid deserts – Dosimetric experiments in the hyperarid core of the Atacama Desert
Authors:
AuthorsInstitution or Email of Authors
Cockell, Charles S.PSSRI, Open University, Milton Keynes, MK7 6AA, UK
McKay, Christopher P.NASA Ames Research Center, Moffett Field, CA 94035-1000, USA
Warren-Rhodes, KimNASA Ames Research Center, Moffett Field, CA 94035-1000, USA
Horneck, GerdaUNSPECIFIED
Date:2008
Journal or Publication Title:Journal of Photochemistry and Photobiology (B: Biology)
Refereed publication:Yes
In ISI Web of Science:No
Volume:90
DOI:doi:10.1016/j.jphotobiol.2007.11.009
Page Range:pp. 79-87
Publisher:Elsevier
Status:Published
Keywords:Atacama, Desiccation, Chroococcidiopsis, Dosimetry, Weathering
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W FR - Forschung unter Weltraumbedingungen (old)
DLR - Research area:Space
DLR - Program:W FR - Forschung unter Weltraumbedingungen
DLR - Research theme (Project):W - Vorhaben Strahlenbiologie (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Aerospace Medicine > Radiation Biology
Deposited By: Kerstin Kopp
Deposited On:25 Feb 2008
Last Modified:27 Apr 2009 14:47

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