Temperature response of soil respiration is dependent on concentration of readily decomposable C

Abstract. Temperature acclimation of soil organic matter (SOM) decomposition is one of the major uncertainties in predicting soil CO2 efflux associated with the increase in global mean temperature. A reasonable explanation for an apparent acclimation proposed by Davidson and colleagues (2006) based on Michaelis-Menten kinetics suggests that temperature sensitivity decreases when both maximal activity of respiratory enzymes (Vmax) and half-saturation constant (Ks) cancel each other upon temperature increase. We tested the hypothesis of the canceling effect by the mathematical simulation of data obtained in incubation experiments with forest and arable soils. Our data support the hypothesis and suggest that concentration of readily decomposable C substrate (as glucose equivalents) and temperature dependent substrate release are the important factors controlling temperature sensitivity of soil respiration. The highest temperature sensitivity of soil respiration was observed when substrate release was temperature dependent and C substrate concentration was much lower than Ks. Increase of substrate content to the half-saturation constant by glucose addition resulted in temperature acclimation associated with the canceling effect. Addition of the substrate to the level providing respiration at a maximal rate Vmax leads to the acclimation of the whole microbial community as such. However, growing microbial biomass was more sensitive to the temperature alterations. This study improves our understanding of the instability of temperature sensitivity of soil respiration under field conditions, attributing this phenomenon to changes in concentration of readily decomposable C substrate.

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Temperature sensitivity of soil respiration is dependent on readily decomposable C substrate concentration

Biogeosciences Discussions ◽

10.5194/bgd-4-2007-2007 ◽

2007 ◽

Vol 4 (3) ◽

pp. 2007-2025 ◽

Cited By ~ 1

Author(s):

A. A. Larionova ◽

I. V. Yevdokimov ◽

S. S. Bykhovets

Keyword(s):

Soil Respiration ◽

Temperature Sensitivity ◽

Substrate Concentration ◽

Maximal Activity ◽

Temperature Acclimation ◽

Co2 Efflux ◽

Arable Soils ◽

Respiratory Enzymes ◽

Half Saturation Constant ◽

Som Decomposition

Abstract. Temperature acclimation of soil organic matter (SOM) decomposition is one of the major uncertainties in predicting soil CO2 efflux by the increase in global mean temperature. A reasonable explanation for an apparent acclimation proposed by Davidson and colleagues (2006) based on Michaelis-Menten kinetics suggests that temperature sensitivity decreases when both maximal activity of respiratory enzymes (Vmax) and half- saturation constant (Ks) cancel each other upon temperature increase. We tested the hypothesis of the canceling effect by the mathematical simulation of the data obtained in the incubation experiments with forest and arable soils. Our data confirm the hypothesis and suggest that concentration of readily decomposable C substrate as glucose equivalent is an important factor controlling temperature sensitivity. The highest temperature sensitivity was observed when C substrate concentration was much lower than Ks. Increase of substrate content to the half-saturation constant resulted in temperature acclimation associated with the canceling effect. Addition of the substrate to the level providing respiration at a maximal rate Vmax leads to the acclimation of the whole microbial community as such. However, growing microbial biomass was more sensitive to the temperature alterations. This study improves our understanding of the instability of temperature sensitivity of soil respiration under field conditions, explaining this phenomenon by changes in concentration of readily decomposable C substrate. It is worth noting that this pattern works regardless of the origin of C substrate: production by SOM decomposition, release into the soil by rhizodeposition, litter fall or drying-rewetting events.

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Significance of soil respiration from biological activity in the degradation processes of different types of organic matter

10.37281/drcsf/1.2.10 ◽

2020 ◽

Vol 1 (2) ◽

pp. 171-179

Keyword(s):

Climate Change ◽

Organic Matter ◽

Soil Moisture ◽

Soil Respiration ◽

Soil Temperature ◽

Temperature Sensitivity ◽

Soil Co2 Efflux ◽

Co2 Efflux ◽

Soil Co2 ◽

Total Soil

Soil respiration is a major component of global carbon cycle. Therefore, it is crucial to understand the environmental controls on soil respiration for evaluating potential response of ecosystems to climate change. In a temperate deciduous forest (located in Northern-Hungary) we added or removed aboveground and belowground litter to determine total soil respiration. We investigated the relationship between total soil CO2 efflux, soil moisture, and soil temperature. Soil CO2 efflux was measured at each plot using soda-lime method. Temperature sensitivity of soil respiration (Q10) was monitored via measuring soil temperature on an hourly basis, while soil moisture was determined monthly. Soil respiration increased in control plots from the second year after implementing the treatment, but results showed fluctuations from one year to another. The effect of doubled litter was less significant than the effect of removal. Removed litter and root inputs caused substantial decrease in soil respiration. We found that temperature was more influential in the control of soil respiration than soil moisture. In plots with no litter Q10 varied in the largest interval. For treatment with doubled litter layer, temperature sensitivity of CO2 efflux did not change considerably. The effect of increasing soil temperature is more conspicuous to soil respiration in litter removal treatments since lack of litter causes greater irradiation. When exclusively leaf litter was considered, the effect of temperature on soil respiration was lower in treatments with added litter than with removed litter. Our results reveal that soil life is impacted by the absence of organic matter, rather than by an excess of organic matter. Results of CO2 emission from soils with different organic matter content can contribute to sustainable land use, considering the changed climatic factors caused by global climate change.

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Interdependencies between temperature and moisture sensitivities of CO<sub>2</sub> emissions in European land ecosystems

Biogeosciences ◽

10.5194/bg-12-5981-2015 ◽

2015 ◽

Vol 12 (20) ◽

pp. 5981-5993 ◽

Cited By ~ 13

Author(s):

C. Gritsch ◽

M. Zimmermann ◽

S. Zechmeister-Boltenstern

Keyword(s):

Carbon Dioxide ◽

Land Use ◽

Soil Respiration ◽

Co2 Emissions ◽

Temperature Sensitivity ◽

Positive Relationship ◽

Co2 Efflux ◽

Moisture Contents ◽

Laboratory Incubation ◽

Land Use Types

Abstract. Soil respiration is one of the largest terrestrial fluxes of carbon dioxide (CO2) to the atmosphere. Hence, small changes in soil respiration rates could have large effects on atmospheric CO2. In order to assess CO2 emissions from diverse European soils with different land-use types and climate (soil moisture and temperature), we conducted a laboratory incubation experiment. Emission measurements of CO2 under controlled conditions were conducted using soil monoliths of nine sites from a European flux network (ÉCLAIRE). The sites are located all over Europe – from the United Kingdom in the west to Ukraine in the east, and from Italy in the south to Finland in the north – and can be separated according to four land-use types (forests, grasslands, arable lands and one peatland). Intact soil cores were incubated in the laboratory in a two-way factorial design, with temperature (5, 10, 15, 20 and 25 °C) and water-filled pore space (WFPS; 5, 20, 40, 60 and 80 %) as the independent variables, while CO2 flux was the response variable. The latter was measured with an automated laboratory incubation measurement system. Land use generally had a substantial influence on carbon dioxide fluxes, with the order of CO2 emission rates of the different land-use types being grassland > peatland > forest/arable land (P < 0.001). CO2 efflux responded strongly to varying temperature and moisture content with optimum moisture contents for CO2 emissions between 40 and 70 % WFPS and a positive relationship between CO2 emissions and temperature. The relationship between temperature and CO2 emissions could be well described by a Gaussian model. Q10 values ranged between 0.86 and 10.85 and were negatively related to temperature for most of the moisture contents and sites investigated. At higher temperatures the effect of water and temperature on Q10 was very low. In addition, under cold temperatures Q10 varied with moisture contents, indicating a stronger prospective effect of rain events in cold areas on temperature sensitivity. At both coniferous forest sites we found a strong increase in the temperature sensitivity at a moisture range between 20 and 40 % WFPS. We developed a new approach to calculate moisture sensitivity (MS) of CO2 efflux. MS was calculated as the slope of a polynomial function of second degree. Moisture sensitivities were highest under dry and wet conditions. In addition we found a positive relationship between MS of CO2 efflux and temperature for both arable lands.

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Temperature response of soil respiration largely unaltered with experimental warming

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1605365113 ◽

2016 ◽

Vol 113 (48) ◽

pp. 13797-13802 ◽

Cited By ~ 149

Author(s):

Joanna C. Carey ◽

Jianwu Tang ◽

Pamela H. Templer ◽

Kevin D. Kroeger ◽

Thomas W. Crowther ◽

...

Keyword(s):

Soil Respiration ◽

Temperature Sensitivity ◽

Boreal Forests ◽

Temperature Response ◽

Experimental Warming ◽

Climatic Warming ◽

Ambient Temperatures ◽

Respiration Rates ◽

Temperature Manipulation ◽

Scientific Attention

The respiratory release of carbon dioxide (CO2) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold of ∼25 °C, above which respiration rates decrease with further increases in temperature. This consistent decrease in temperature sensitivity at higher temperatures demonstrates that rising global temperatures may result in regionally variable responses in soil respiration, with colder climates being considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic warming.

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Measurement depth effects on the apparent temperature sensitivity of soil respiration in field studies

Biogeosciences Discussions ◽

10.5194/bgd-5-1867-2008 ◽

2008 ◽

Vol 5 (3) ◽

pp. 1867-1898 ◽

Cited By ~ 5

Author(s):

A. Graf ◽

L. Weihermüller ◽

J. A. Huisman ◽

M. Herbst ◽

J. Bauer ◽

...

Keyword(s):

Soil Respiration ◽

Temperature Measurement ◽

Temperature Sensitivity ◽

Field Experiments ◽

Soil Surface ◽

Field Measurements ◽

Apparent Temperature ◽

Time Averaging ◽

Co2 Efflux ◽

Measurement Depth

Abstract. CO2 efflux at the soil surface is the result of respiration in different depths that are subjected to variable temperatures at the same time. Therefore, the temperature measurement depth affects the apparent temperature sensitivity of field-measured soil respiration. We summarize existing literature evidence on the importance of this effect, and describe a simple model to understand and estimate the magnitude of this potential error source for heterotrophic respiration. The model is tested against field measurements. We discuss the influence of climate (annual and daily temperature amplitude), soil properties (vertical distribution of CO2 sources, thermal and gas diffusivity), and measurement schedule (frequency, study duration, and time averaging). Q10 as a commonly used parameter describing the temperature sensitivity of soil respiration is taken as an example and computed for different combinations of the above conditions. We define conditions and data acquisition and analysis strategies that lead to lower errors in field-based Q10 determination. It was found that commonly used temperature measurement depths are likely to result in an underestimation of temperature sensitivity in field experiments. Our results also apply to activation energy as an alternative temperature sensitivity parameter.

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Interdependencies between temperature and moisture sensitivities of CO<sub>2</sub> emissions in European land ecosystems

Biogeosciences Discussions ◽

10.5194/bgd-12-4433-2015 ◽

2015 ◽

Vol 12 (6) ◽

pp. 4433-4464 ◽

Cited By ~ 1

Author(s):

C. Gritsch ◽

M. Zimmermann ◽

S. Zechmeister-Boltenstern

Keyword(s):

Carbon Dioxide ◽

Land Use ◽

Soil Moisture ◽

Soil Respiration ◽

Co2 Emissions ◽

Temperature Sensitivity ◽

Positive Relationship ◽

Co2 Efflux ◽

Land Uses ◽

Moisture Contents

Abstract. Soil respiration is one of the largest terrestrial fluxes of carbon dioxide (CO2) to the atmosphere. Hence, small changes in soil respiration rates could have large effects on atmospheric CO2. In order to assess CO2 emissions from diverse European soils under different land-use and climate (soil moisture and temperature) we conducted a laboratory incubation experiment. Emission measurements of carbon dioxide under controlled conditions were conducted using soil monoliths of nine sites from the ÉCLAIRE flux network. Sites are located all over Europe; from the UK in the west to the Ukraine in the east; Italy in the south to Finland in the north and can be separated according to four land-uses (forests, grasslands, arable lands and one peatland). Intact soil cores were incubated in the laboratory at the temperatures 5, 10, 15, 20, and 25 °C in a two factorial design of five soil moisture levels (5, 20, 40, 60, 80 (100)% water filled pore space, WFPS), before analysed for CO2 fluxes with an automated laboratory incubation measurement system. Land-use generally had a substantial influence on carbon dioxide fluxes, with the order of CO2 emission rates of the different land-uses being grassland > peatland > forest/arable land (P < 0.001). CO2 efflux responded strongly to varying temperature and moisture content with optimum moisture contents for CO2 emissions between 40–70% WFPS and a positive relationship between CO2 emissions and temperature. The relationship between temperature and CO2 emissions could be well described by a Gaussian model. Q10 values ranged between 0.86–10.85 and were negatively related to temperature for most of the moisture contents and sites investigated. At higher temperatures the effect of water and temperature on Q10 was very low. In addition under cold temperatures Q10 varied with moisture contents indicating a stronger prospective effect of rain events in cold areas on temperature sensitivity. We found at both coniferous forest sites a strong increase of the temperature sensitivity at a moisture range between 20–40% WFPS. In our study moisture sensitivity (MS) of CO2 efflux was calculated as the slope of a polynomial function of second degree. Moisture sensitivities were highest under dry and wet conditions. In addition we found a positive relationship between MS of CO2 efflux and temperature for both arable lands.

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