Temperature sensitivity of SOM decomposition is linked with a K‐selected microbial community

2021 ◽  
Author(s):  
Hui Li ◽  
Shan Yang ◽  
Mikhail V. Semenov ◽  
Fei Yao ◽  
Ji Ye ◽  
...  
Keyword(s):  
Microbial Community ◽  
Temperature Sensitivity ◽  
Som Decomposition

Temperature Sensitivity of Intracellular and Extracellular Soil Enzyme Activities

2021 ◽  
Author(s):  
Adetunji Alex Adekanmbi ◽  
Laurence Dale ◽  
Liz Shaw ◽  
Tom Sizmur
Keyword(s):  
Enzyme Activity ◽  
Soil Temperature ◽  
Temperature Sensitivity ◽  
Extracellular Enzymes ◽  
Extracellular Enzyme ◽  
Daily Maximum ◽  
Temperature Sensitive ◽  
Intracellular Enzyme ◽  
Temperature Changes ◽  
Som Decomposition

<p>Predicting the pattern of soil organic matter (SOM) decomposition as a feedback to climate change, via release of CO<sub>2</sub>, is extremely complex and has received much attention. However, investigations often do not differentiate between the extracellular and intracellular processes involved and work is needed to identify their relative temperature sensitivities. Samples were collected from a grassland soil at Sonning, UK with average daily maximum and minimum soil temperature of 15 °C and 5 °C. We measured potential activities of β-glucosidase (BG) and chitinase (NAG) (extracellular enzymes) and glucose-induced CO<sub>2 </sub>respiration (intracellular enzymes) at a range of assay temperatures (5 °C, 15 °C, 26 °C, 37<sup>  </sup>°C, and 45 °C). The temperature coefficient Q<sub>10</sub> (the increase in enzyme activity that occurs after a 10 °C increase in soil temperature) was calculated to assess the temperature sensitivity of intracellular and extracellular enzymes activities. Between 5 °C and 15 °C intracellular and extracellular enzyme activities had equal temperature sensitivity, but between 15 °C and 26°C intracellular enzyme activity was more temperature sensitive than extracellular enzyme activity and between 26 °C and 37 °C extracellular enzyme activity was more temperature sensitive than intracellular enzyme activity. This result implies that extracellular depolymerisation of higher molecular weight organic compounds is more sensitive to temperature changes at higher temperatures (e.g. changes to daily maximum summer temperature) but the intracellular respiration of the generated monomers is more sensitive to temperature changes at moderate temperatures (e.g. changes to daily mean summer temperature). We therefore conclude that the extracellular and intracellular steps of SOM mineralisation are not equally sensitive to changes in soil temperature. The finding is important because we have observed greater increases in average daily minimum temperatures than average daily mean or maximum temperatures due to increased cloud cover and sulphate aerosol emission. Accounting for this asymmetrical global warming may reduce the importance of extracellular depolymerisation and increase the importance of intracellular catalytic activities as the rate limiting step of SOM decomposition.</p>

scholarly journals Temperature sensitivity of soil respiration rates enhanced by microbial community response

Nature ◽  
2014 ◽  
Vol 513 (7516) ◽  
pp. 81-84 ◽  
Author(s):  
Kristiina Karhu ◽  
Marc D. Auffret ◽  
Jennifer A. J. Dungait ◽  
David W. Hopkins ◽  
James I. Prosser ◽  
...  
Keyword(s):  
Microbial Community ◽  
Soil Respiration ◽  
Temperature Sensitivity ◽  
Community Response ◽  
Respiration Rates

scholarly journals Changes in the temperature sensitivity of SOM decomposition with grassland succession: implications for soil C sequestration

2013 ◽  
Vol 3 (15) ◽  
pp. 5045-5054 ◽  
Author(s):  
He Nianpeng ◽  
Wang Ruomeng ◽  
Gao Yang ◽  
Dai Jingzhong ◽  
Wen Xuefa ◽  
...  
Keyword(s):  
Temperature Sensitivity ◽  
C Sequestration ◽  
Soil C ◽  
Soil C Sequestration ◽  
Som Decomposition

scholarly journals Differences in SOM Decomposition and Temperature Sensitivity among Soil Aggregate Size Classes in a Temperate Grasslands

PLoS ONE ◽  
2015 ◽  
Vol 10 (2) ◽  
pp. e0117033 ◽  
Author(s):  
Qing Wang ◽  
Dan Wang ◽  
Xuefa Wen ◽  
Guirui Yu ◽  
Nianpeng He ◽  
...  
Keyword(s):  
Temperature Sensitivity ◽  
Aggregate Size ◽  
Soil Aggregate ◽  
Temperate Grasslands ◽  
Size Classes ◽  
Som Decomposition

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

2007 ◽  
Vol 4 (3) ◽  
pp. 2007-2025 ◽  
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.

scholarly journals Lower Soil Carbon Loss Due to Persistent Microbial Adaptation to Climate Warming

2020 ◽  
Author(s):  
Xue Guo ◽  
Qun Gao ◽  
Mengting Yuan ◽  
Gangsheng Wang ◽  
Xishu Zhou ◽  
...  
Keyword(s):  
Microbial Community ◽  
Climate Warming ◽  
Temperature Sensitivity ◽  
Microbial Respiration ◽  
Ecosystem Model ◽  
Soil C ◽  
Spatial And Temporal Scales ◽  
Soil Microbial ◽  
Soil Microbial Respiration ◽  
C Cycle

AbstractSoil microbial respiration is an important source of uncertainty in projecting future climate and carbon (C) cycle feedbacks. Despite intensive studies for two decades, the magnitude, direction, and duration of such feedbacks are uncertain, and their underlying microbial mechanisms are still poorly understood. Here we examined the responses of soil respiration and microbial community structure to long-term experimental warming in a temperate grassland ecosystem. Our results indicated that the temperature sensitivity of soil microbial respiration (i.e., Q10) persistently decreased by 12.0±3.7% across 7 years of warming. Integrated metagenomic and functional analyses showed that microbial community adaptation played critical roles in regulating respiratory acclimation. Incorporating microbial functional gene abundance data into a microbially-enabled ecosystem model significantly improved the modeling performance of soil microbial respiration by 5–19%, compared to the traditional non-microbial model. Model parametric uncertainty was also reduced by 55–71% when gene abundances were used. In addition, our modeling analyses suggested that decreased temperature sensitivity could lead to considerably less heterotrophic respiration (11.6±7.5%), and hence less soil C loss. If such microbially mediated dampening effects occur generally across different spatial and temporal scales, the potential positive feedback of soil microbial respiration in response to climate warming may be less than previously predicted.

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