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Effects of soil frost on growth, composition and respiration of the soil microbial decomposer community

Author:
  • Mahsa Haei
  • Johannes Rousk
  • Ulrik Ilstedt
  • Mats Oquist
  • Erland Bååth
  • Hjalmar Laudon
Publishing year: 2011
Language: English
Pages: 2069-2077
Publication/Series: Soil Biology & Biochemistry
Volume: 43
Issue: 10
Document type: Journal article
Publisher: Elsevier

Abstract english

Most climate change scenarios predict that the variability of weather conditions will increase in coming decades. Hence, the frequency and intensity of freeze-thaw cycles in high-latitude regions are likely to increase, with concomitant effect on soil carbon biogeochemistry and associated microbial processes. To address this issue we sampled riparian soil from a Swedish boreal forest and applied treatments with variations in four factors related to soil freezing (temperature, treatment duration, soil water content and frequency of freeze-thaw cycles), at three levels in a laboratory experiment, using a Central Composite Face-centred (CCF) experimental design. We then measured bacterial (leucine incorporation) and fungal (acetate in ergosterol incorporation) growth, basal respiration, soil microbial phospholipid fatty acid (PLFA) composition, and concentration of dissolved organic carbon (DOC). Fungal growth was higher in soil exposed to freeze-thawing perturbations and freezing temperatures of -6 degrees C and -12 degrees C, than under more constant conditions (steady 0 degrees C). The opposite pattern was found for bacteria, resulting in an increasing fungal-to-bacterial growth ratio following more intensive winter conditions. Soil respiration increased with water content, decreased with treatment duration and appeared to mainly be driven by treatment-induced changes in the DOC concentration. There was a clear shift in the PLFA composition at 0 degrees C, compared with the two lower temperatures, with PLFA markers associated with fungi as well as a number of unsaturated PLFAs being relatively more common at 0 degrees C. Shifts in the PLFA pattern were consistent with those expected for phenotypic plasticity of the cell membrane to low temperatures. There were small declines in PLFA concentrations after freeze-thawing and with longer durations. However, the number of freeze-thaw events had no effect on the microbiological variables. The findings suggest that the higher frequency of freeze-thaw events predicted to follow the global warming will likely have a limited impact on soil microorganisms. (C) 2011 Elsevier Ltd. All rights reserved.

Keywords

  • Biological Sciences
  • Bacterial growth
  • Fungal growth
  • Frost
  • Dissolved organic carbon (DOC)
  • PLFA
  • Respiration

Other

Published
  • Effect of environmental factors on fungal and bacterial growth in soil
  • Carbon drivers and microbial agents of soil respiration
  • Microbial carbon-use efficiency
  • BECC
  • Microbial Ecology
  • ISSN: 0038-0717
Erland Bååth
E-mail: erland [dot] baath [at] biol [dot] lu [dot] se

Professor emeritus

MEMEG

+46 46 222 42 64

E-F210

Sölvegatan 37, Lund

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