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Prolonged drought changes the bacterial growth response to rewetting

Author:
  • Annelein Meisner
  • Johannes Rousk
  • Erland Bååth
Publishing year: 2015
Language: English
Pages: 314-322
Publication/Series: Soil Biology & Biochemistry
Volume: 88
Document type: Journal article
Publisher: Elsevier

Abstract english

Rewetting a dry soil can result in two response patterns of bacterial growth and respiration. In type 1, bacterial growth starts to increase linearly immediately upon rewetting and respiration rates are highest immediately upon rewetting. In type 2, bacterial growth starts to increase exponentially after a lag period with a secondary increase in respiration occurring at the start of the exponential increase in growth. We previously observed that the type 1 response occurred after rewetting 4-day dried soil and type 2 for 1-year dried soil. Here we studied in detail how the duration of drought related to the two types of responses of bacterial growth and respiration to rewetting. Soil was air dried for different time periods from 4 days up to 48 weeks. Upon rewetting, bacterial growth and respiration was measured repeatedly at 17 °C during one week. Drought periods of ≤2 weeks resulted in a type 1 response whereas drought periods of ≥4 weeks resulted in a type 2 response. The lag period increased with drought duration and reached a maximum of ca. 18 h. The bacterial growth response was also affected by incubation of moist soil before drying–rewetting. The lag period increased with duration of moist soil incubation before the 4-day drying–rewetting event and reached also a maximum of ca. 18 h. The exponential growth increase in the type 2 response coincided with a secondary increase in respiration, which increased in magnitude with increasing drought duration. Cumulative respiration increased with drought duration and was ca. 4 times higher after 48 weeks of drought compared to 4 days. Thus, prolonged drought affected the response type of bacterial growth and respiration to rewetting, and also increased lag period, the magnitude of the secondary increase in respiration and total C release. The effect of drought was, however, modified by the lenght of the incubation period of moist soil before drought, suggesting that soil conditions before a drying–rewetting event need consideration when evaluating microbial responses.

Keywords

  • Microbiology

Other

Published
  • Responses of soil microbes to drought and rewetting
  • MICCS - Molecular Interactions Controlling soil Carbon Sequestration
  • Microbial Ecology
  • ISSN: 0038-0717
Annelein Meisner
E-mail: annelein [dot] meisner [at] biol [dot] lu [dot] se

Postdoctoral fellow

MEMEG

+46 46 222 37 63

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