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

By M. Spohn. 2014

174 citations recorded by the source corpus.

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.

Subfields: Civil and Structural Engineering, Ecology, Soil Science

View Paper: https://www.semanticscholar.org/paper/1da05ad725e4212af67c85ed64487a482d3d407b

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Citations in the corpus

Phosphorus availability and microbial community in the rhizosphere of intercropped cereal and legume along a P-fertilizer gradient (2016, background): “Nutrient-limitation of soil microbial communities in the rhizosphere has already been previously demonstrated (e.g. Heuck et al. 2015; Spohn 2015), but an interesting finding in the present work is the difference between the two studied crop species.”
Trends in soil microbial communities during secondary succession (2017, background): “This is consistent with recent results from experiments (Spohn and Chodak, 2015; Zhou et al., 2017), metaanalyses (Spohn, 2015; Zhou and Wang, 2015; Xu et al., 2017), and modeling studies (Xu et al., 2014).”
Stoichiometry of microbial carbon use efficiency in soils (2016, methodology): “To estimate growth (μ) from biomass, we normalized this regression to our data (i.e., shifted the intercept) by assuming a specific growth rate of 0.001 h −1 at mean biomass concentration (62.2 mol C/g), based on a mean q CO 2 of 0.003 h −1 for soil microbes (Spohn 2015) and a mean CUE of 0.25.”
Element cycling as driven by stoichiometric homeostasis of soil microorganisms (2016, background): “…changes in the microbial commuity composition (Fanin, Fromin, Buatois, & Hättenschwiler, b P b 013; Tischer, Potthast, & Hamer, 2014; Heuck, Weig, & pohn, 2015), and second, by storage of C and P present n excess with respect to the microbial demands (Hessen Anderson, 2008; Mooshammer, Wanek,…”
Stoichiometric responses of soil microflora to nutrient additions for two temperate forest soils (2017, background): “For example, a field study (Spohn and Chodak 2015) and a metaanalysis (Spohn 2015) found that microbial respiration rate per unit microbial biomass (i.e., microbial metabolic quotient, qCO2) increased with C/N or C/P of resources, suggesting that microbes dispose C via overflow respiration if they…”