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

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Bacterial immobilization and remineralization of N at different growth rates and N concentrations. / Bengtson, Per; Bengtsson, Göran.

I: FEMS microbiology ecology, Vol. 54, Nr. 1, 2005, s. 13-19.

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TY - JOUR

T1 - Bacterial immobilization and remineralization of N at different growth rates and N concentrations

AU - Bengtson, Per

AU - Bengtsson, Göran

PY - 2005

Y1 - 2005

N2 - 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.

AB - 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.

U2 - 10.1016/j.femsec.2005.02.006

DO - 10.1016/j.femsec.2005.02.006

M3 - Article

VL - 54

SP - 13

EP - 19

JO - FEMS microbiology ecology

T2 - FEMS microbiology ecology

JF - FEMS microbiology ecology

SN - 1574-6941

IS - 1

ER -