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Temperature sensitivity of bacterial growth in a hot desert soil with large temperature fluctuations

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Author

Summary, in English

Hot desert ecosystems are characterized by high soil temperatures with large fluctuations annually and diurnally. Thus, one could hypothesize that not only the microbial community would be adapted to high temperatures, but also have a large temperature range conducive for growth. We determined the temperature sensitivity of the soil bacterial community from the Chihuahuan Desert, Big Bend National Park, Texas, USA, using leucine incorporation as a proxy for bacterial growth. Soil samples were taken during early spring and mid-summer from the surface (0-5 cm) and deeper (15-20 cm) soil layers. Mean winter soil temperature preceding the spring samples was 15 degrees C and in summer 36 degrees C at both depths, but with larger amplitude in the top soil than deeper down. T-min was significantly lower in the top 0-5 cm than at 15-20 cm, -1.2 and 0.0 degrees C, respectively. T-opt also was higher in the top soil than deeper down, 42.9 and 41.4 degrees C, respectively, resulting in a larger temperature range for growth (T-opt - T-min) in the top soil reflecting the larger temperature fluctuations in this layer. There were no significant differences in cardinal temperatures for bacterial growth in soils sampled in early spring and mid-summer despite large seasonal differences in temperatures, showing that long periods of colder temperatures was less important than periods of high temperatures as selection pressure for temperature sensitivity. Comparing with earlier results from Antarctic soils (Rinnan et al., 2009), which in contrast represent an extremely low temperature environment, we suggest that the range of temperature cardinal temperatures for soil bacterial communities globally varies from around -15 to 0 degrees C for T-min and 25 to 45 degrees C for T-opt. (C) 2013 Elsevier Ltd. All rights reserved.

Publishing year

2013

Language

English

Pages

180-185

Publication/Series

Soil Biology & Biochemistry

Volume

65

Document type

Journal article

Publisher

Elsevier

Topic

  • Biological Sciences

Keywords

  • Temperature sensitivity
  • Bacterial growth
  • Desert
  • Leucine
  • incorporation
  • Temperature fluctuations
  • Community adaptation

Status

Published

ISBN/ISSN/Other

  • ISSN: 0038-0717