Soil extracellular enzymes explain soil carbon accumulation under elevated CO2-data and figure code from YZhang

Here, we conducted a global meta-analysis to evaluate the potential capacity of the soil microbiome to degrade organic matter under eCO2. We also evaluated the relative capacity of the soil microbiome to degrade labile versus recalcitrant carbon sources after different periods of eCO2 exposure. For this, we built a database of 272 observations of soil carbon-degrading extracellular enzymes from 71 eCO2 studies across four continents. Classic meta-analysis and random forest analysis were combined to quantify the relative importance of potential predictors in explaining the effects of eCO2 on EEAs and SOC. This approach allowed us to assess the role of EEAs in affecting SOC under eCO2 across a wide range of climatic, edaphic, and experimental conditions. Specifically, our study aimed (a) to quantify the effects of eCO2 on cellulase and ligninase activities, (b) to identify the edaphoclimatic factors affecting the responses of cellulase and ligninase activities to eCO2, and (c) to explore links between eCO2-induced shifts in cellulase and ligninase activities and changes in SOC.