Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 12, issue 3
Biogeosciences, 12, 817–823, 2015
https://doi.org/10.5194/bg-12-817-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 12, 817–823, 2015
https://doi.org/10.5194/bg-12-817-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 10 Feb 2015

Research article | 10 Feb 2015

Microbial respiration per unit microbial biomass depends on litter layer carbon-to-nitrogen ratio

M. Spohn M. Spohn
  • Department of Soil Ecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany

Abstract. Soil microbial respiration is a central process in the terrestrial carbon (C) cycle. In this study, I tested the effect of the carbon-to-nitrogen (C:N) ratio of soil litter layers on microbial respiration in absolute terms and per unit microbial biomass C. For this purpose, a global data set on microbial respiration per unit microbial biomass C – termed the metabolic quotient (qCO2) – was compiled from literature data. It was found that qCO2 in the soil litter layers was positively correlated with the litter C:N ratio and was negatively correlated with the litter nitrogen (N) concentration. The positive relation between qCO2 and the litter C:N ratio resulted from an increase in respiration with the C:N ratio in combination with no significant effect of the litter C:N ratio on the soil microbial biomass C concentration. The results suggest that soil microorganisms respire more C both in absolute terms and per unit microbial biomass C when decomposing N-poor substrate. The reasons for the observed relationship between qCO2 and the litter layer C:N ratio could be microbial N mining, overflow respiration or the inhibition of oxidative enzymes at high N concentrations. In conclusion, the results show that qCO2 increases with the litter layer C:N ratio. Thus, the findings indicate that atmospheric N deposition, leading to decreased litter C:N ratios, might decrease microbial respiration in soils.

Publications Copernicus
Download
Short summary
Soil microbial respiration is a central process in the terrestrial carbon (C) cycle. In this study, I tested the effect of the carbon-to-nitrogen (C:N) ratio of soil litter layers on microbial respiration in absolute terms and per unit microbial biomass C. For this purpose, a global dataset on microbial respiration per unit microbial biomass C – termed the metabolic quotient (qCO2) – was compiled form literature data. It was found that the qCO2 in the soil litter layers was positively correlated
Soil microbial respiration is a central process in the terrestrial carbon (C) cycle. In this...
Citation