Carbon use efficiency of microbial communities: stoichiometry, methodology and modelling

Sinsabaugh, Robert L.; Manzoni, Stefano; Moorhead, Daryl L.; Richter, Andreas

doi:10.1111/ele.12113

Cited by 729 publications

(646 citation statements)

References 96 publications

(242 reference statements)

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“…Indeed, models of SOM decomposition based on studies that use monomers alone may overestimate a CUE value (Sinsabaugh et al 2013), which agrees with our findings with the CUE of glucose being significantly higher than of cellulose. Another substrate quality-related factor that affects the CUE is that different monomers are metabolized via different metabolic pathways and therefore yield different respiration rates per unit carbon assimilated, i.e.…”

Section: Discussionsupporting

confidence: 92%

The effect of temperature and substrate quality on the carbon use efficiency of saprotrophic decomposition

et al. 2016

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Background and aims Mineralization of soil organic matter (SOM) constitutes a major carbon flux to the atmosphere. The carbon use efficiency (CUE) of the saprotrophic microorganisms mineralizing SOM is integral for soil carbon dynamics. Here we investigate how the CUE is affected by temperature, metabolic conditions, and the molecular complexity of the substrate. Methods We incubated O-horizon soil samples (with either 13 C-glucose or 13 C-cellulose) from a boreal coniferous forest at 4, 9, 14, and 19°C, and calculated CUEs based on the amount of 13 C-CO 2 and 13 C-labelled microbial biomass produced. The effects of substrate, temperature, and metabolic conditions (representing unlimited substrate supply and substrate limitation) on CUE were evaluated. Results CUE from metabolizing glucose was higher as compared to cellulose. A slight decrease in CUE with increasing temperature was observed in glucose amended samples (but only in the range 9-19°C), but not in cellulose amended samples. CUE differed significantly with metabolic conditions, i.e. CUE was higher during unlimited growth conditions as compared to conditions with substrate limitation. Conclusions We conclude that it is integral to account for both differences in CUE during different metabolic phases, as well as complexity of substrate, when interpreting temperature dependence on CUE in incubation studies.

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Section: Discussionsupporting

confidence: 92%

The effect of temperature and substrate quality on the carbon use efficiency of saprotrophic decomposition

et al. 2016

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“…Major factors affecting microbial activities include environmental factors (for example, soil temperature and moisture; Brockett et al, 2012), carbon availability or root exudation (Drake et al, 2013) and nutrient availability (Lennon and Jones, 2011). Changes in these factors might result in changes in CUE (Sinsabaugh et al, 2013) and transitions between microbial physiological states (active and dormant), particularly in laboratoryscale experiments. For example, dormancy is a beneficial survival and evolutionary trait of soil microbes when faced with unfavorable environmental conditions (Lennon and Jones, 2011).…”

Section: Microbial Dormancymentioning

confidence: 99%

“…Alternatively, measurements of microbial biomass such as chloroform fumigation and quantitative polymerase chain reaction cannot readily inform microbial models unless the extent of dormancy is considered . Although soil respiration data are the most available and reliable observations for calibration and validation of models from point to global scale (Raich and Schlesinger, 1992;Hanson et al, 2000), estimates of microbial biomass, and even stoichiometry, will ultimately be needed to parameterize microbial ecosystem models (Sinsabaugh et al, 2013;Xu et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Microbial dormancy improves development and experimental validation of ecosystem model

et al. 2014

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Climate feedbacks from soils can result from environmental change followed by response of plant and microbial communities, and/or associated changes in nutrient cycling. Explicit consideration of microbial life-history traits and functions may be necessary to predict climate feedbacks owing to changes in the physiology and community composition of microbes and their associated effect on carbon cycling. Here we developed the microbial enzyme-mediated decomposition (MEND) model by incorporating microbial dormancy and the ability to track multiple isotopes of carbon. We tested two versions of MEND, that is, MEND with dormancy (MEND) and MEND without dormancy (MEND_wod), against long-term (270 days) carbon decomposition data from laboratory incubations of four soils with isotopically labeled substrates. MEND_wod adequately fitted multiple observations (total C-CO 2 and 14 C-CO 2 respiration, and dissolved organic carbon), but at the cost of significantly underestimating the total microbial biomass. MEND improved estimates of microbial biomass by 20-71% over MEND_wod. We also quantified uncertainties in parameters and model simulations using the Critical Objective Function Index method, which is based on a global stochastic optimization algorithm, as well as model complexity and observational data availability. Together our model extrapolations of the incubation study show that long-term soil incubations with experimental data for multiple carbon pools are conducive to estimate both decomposition and microbial parameters. These efforts should provide essential support to future field-and globalscale simulations, and enable more confident predictions of feedbacks between environmental change and carbon cycling.

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“…Carbon saturation theory suggests that soils have a limited capacity to stabilize organic C and that this capacity may be regulated by intrinsic soil properties such as clay concentration and mineralogy (Hassink, 1997;Six et al, 2002). Clay mineral surfaces stabilize and protect organic C through mineral organic complexes, leading to reduced C decomposition rates (Baldock and Skjemstad, 2000).…”

Section: M White Et Al: Implications Of Carbon Saturation Model mentioning

confidence: 99%

“…This phenomenon results in an asymptotic response of soil organic C stocks to increasing C inputs (Stewart et al, 2007;Gulde et al, 2008;Heitkamp et al, 2012). Six et al (2002) proposed a conceptual model of C protection based on measurable pools of organic C, including siltand clay-associated C pools and particulate organic matter C pools. Several studies have indicated that the silt-and clayassociated C pools exhibit a saturating C storage response to increasing C inputs, while particulate organic matter increases linearly with C inputs (Gulde et al, 2008;Stewart et al, 2008;Stewart et al, 2012).…”

Section: M White Et Al: Implications Of Carbon Saturation Model mentioning

confidence: 99%

Implications of carbon saturation model structures for simulated nitrogen mineralization dynamics

2014

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Abstract. Carbon (C) saturation theory suggests that soils have a limited capacity to stabilize organic C and that this capacity may be regulated by intrinsic soil properties such as clay concentration and mineralogy. While C saturation theory has advanced our ability to predict soil C stabilization, few biogeochemical ecosystem models have incorporated C saturation mechanisms. In biogeochemical models, C and nitrogen (N) cycling are tightly coupled, with C decomposition and respiration driving N mineralization. Thus, changing model structures from non-saturation to C saturation dynamics can change simulated N dynamics. In this study, we used C saturation models from the literature and of our own design to compare how different methods of modeling C saturation affected simulated N mineralization dynamics. Specifically, we tested (i) how modeling C saturation by regulating either the transfer efficiency (ε, g C retained g −1 C respired) or transfer rate (k) of C to stabilized pools affected N mineralization dynamics, (ii) how inclusion of an explicit microbial pool through which C and N must pass affected N mineralization dynamics, and (iii) whether using ε to implement C saturation in a model results in soil texture controls on N mineralization that are similar to those currently included in widely used non-saturating C and N models. Models were parameterized so that they rendered the same C balance. We found that when C saturation is modeled using ε, the critical C : N ratio for N mineralization from decomposing plant residues (r cr ) increases as C saturation of a soil increases. When C saturation is modeled using k, however, r cr is not affected by the C saturation of a soil. Inclusion of an explicit microbial pool in the model structure was necessary to capture short-term N immobilization-mineralization turnover dynamics during decomposition of low N residues. Finally, modeling C saturation by regulating ε led to similar soil texture controls on N mineralization as a widely used non-saturating model, suggesting that C saturation may be a fundamental mechanism that can explain N mineralization patterns across soil texture gradients. These findings indicate that a coupled C and N model that includes saturation can (1) represent short-term N mineralization by including a microbial pool and (2) express the effects of texture on N turnover as an emergent property.

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Carbon use efficiency of microbial communities: stoichiometry, methodology and modelling

Cited by 729 publications

References 96 publications

The effect of temperature and substrate quality on the carbon use efficiency of saprotrophic decomposition

The effect of temperature and substrate quality on the carbon use efficiency of saprotrophic decomposition

Microbial dormancy improves development and experimental validation of ecosystem model

Implications of carbon saturation model structures for simulated nitrogen mineralization dynamics

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