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Bacterial immobilization and remineralization of N at different growth rates and N concentrations

  • Per Bengtson
  • Göran Bengtsson
Publishing year: 2005
Language: English
Pages: 13-19
Publication/Series: FEMS microbiology ecology
Volume: 54
Issue: 1
Document type: Journal article
Publisher: Elsevier

Abstract english

An experiment was designed to resolve two largely unaddressed questions about the turnover of N in soils. One is the influence of microbial growth rate on mobilization and remineralization of cellular N. The other is to what extent heterotrophic immobilization of NO3- is controlled by the soil concentration of NH4+. Bacteria were extracted from a deciduous forest soil and inoculated into an aqueous medium. Various N pool dilution/enrichment experiments were carried out to: (1) calculate the gross N immobilization and remineralization rates; (2) investigate their dependence on NH4+ and NO3- concentrations; (3) establish the microbial preference for NH4+ and NO3- depending on the NH4+/NO3- concentration ratio. Remineralization of microbial N occurred mainly at high growth rates and NH4+ concentrations. There was a positive correlation between NH4+ immobilization and remineralization rates, and intracellular recycling of N seemed to be an efficient way for bacteria to withstand low inorganic N concentrations. Thus, extensive remineralization of microbial N is likely to occur only when environmental conditions promote high growth rates. The results support previous observations of high NO3- immobilization rates, especially at low NH4+ concentrations, but NO3- was also immobilized at high NH4 concentrations. The latter can be understood if part of the microbial community has a preference for NO3- over NH4+ (c) 2005 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.


  • Ecology
  • Biological Sciences


  • Microbial Ecology
  • ISSN: 1574-6941
Per Bengtson
E-mail: per [dot] bengtson [at] biol [dot] lu [dot] se



+46 46 222 37 60


Sölvegatan 37, Lund


Research group

Microbial Ecology


Doctoral students and postdocs

PhD students, main supervisor


PhD students, assistant supervisor

Jian Li

Experimental setup