EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Drivers of soil microbial activities and greenhouse gas emissions along an elevational gradient 

Xingguo Han1, Anna Doménech Pascual2, Joan Pere Casas-Ruiz2, Jonathan Donhauser3,4, Karen Jordaan5, Jean-Baptiste Ramond5,6, Anders Priemé3,4, Anna M. Romaní2, and Aline Frossard1
Xingguo Han et al.
  • 1Swiss Federal Research Institute WSL, Switzerland (
  • 2Institute of Aquatic Ecology, University of Girona, Girona, Spain
  • 3Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark
  • 4Centre for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark
  • 5Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
  • 6Departamento de Genética Molecular Y Microbiología, Facultad de Ciencias Biológicas, Pontifcia Universidad Católica de Chile, Santiago, Chile

Mountain ecosystems contribute substantially to global carbon and nitrogen biogeochemical cycles. Although soil respiration, and microbial biomass, activities and diversity have been extensively studied at different altitudes worldwide, little is known on causal link between environmental drivers, microbial functions and emissions of greenhouse gases (GHGs) in soils of different elevation. Here, by measuring in-situ GHG fluxes, soil properties, organic matter (OM) quality, microbial enzyme activities, biomass and gene abundances, we investigate factors that control long-term GHG fluxes (carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)) in natural soils with an elevational gradient of ~2400 m across Switzerland with different vegetation covers. Results showed that CO2 and N2O fluxes increased significantly with elevation from top to the treeline, but slightly decreased from the treeline to bottom. Contrastingly, no significantly patterns of CH4 fluxes across the whole elevation were observed. Spearman correlations revealed that the increased CO2 and N2O fluxes were highly correlated to the significant increases in soil temperature, moisture, organic matter (OM) quantity and quality (increases in the relative contribution of humic-like vs. fresh-like OM), bacterial and fungal biomass and gene abundances. Structural equation model, hierarchical partitioning and random forest regression further confirmed that, in addition to soil temperature and moisture, SOM quantity and quality are the most driving factors of microbial activity and respiration. Our study highlights the importance of OM quality as a driving factor of soil microbial metabolic activities in Alpine soils across the elevation, and predicts a potential increase in GHG emissions in high-altitudinal soils with the expected upwarding-shifting treeline under climate warming.

How to cite: Han, X., Pascual, A. D., Casas-Ruiz, J. P., Donhauser, J., Jordaan, K., Ramond, J.-B., Priemé, A., Romaní, A. M., and Frossard, A.: Drivers of soil microbial activities and greenhouse gas emissions along an elevational gradient , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9252,, 2023.