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The effect of low temperature on Antarctic endolithic green algaeLaboratory experiments show that undercooling to about -5 degrees C occurs in colonized Beacon sandstones of the Ross Desert, Antarctica. High-frequency temperature oscillations between 5 degrees C and -5 degrees C or -10 degrees C (which occur in nature on the rock surface) did not damage Hemichloris antarctica. In a cryomicroscope, H. antarctica appeared to be undamaged after slow or rapid cooling to -50 degrees C. 14CO2 incorporation after freezing to -20 degrees C was unaffected in H. antarctica or in Trebouxia sp. but slightly depressed in Stichococcus sp. (isolated from a less extreme Antarctic habitat). These results suggest that the freezing regime in the Antarctic desert is not injurious to endolithic algae. It is likely that the freezing-point depression inside the rock makes available liquid water for metabolic activity at subzero temperatures. Freezing may occur more frequently on the rock surface and contribute to the abiotic nature of the surface.
Document ID
20040090076
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Meyer, M. A.
(Florida State University Tallahassee 32306-2043, United States)
Morris, G. J.
Friedmann, E. I.
Date Acquired
August 21, 2013
Publication Date
January 1, 1988
Publication Information
Publication: Polarforschung
Volume: 58
Issue: 3-Feb
ISSN: 0032-2490
Subject Category
Exobiology
Funding Number(s)
CONTRACT_GRANT: NSG-7337
CONTRACT_GRANT: DPP-8314180
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 52-30
NASA Discipline Exobiology
Non-NASA Center
NASA Program Exobiology

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