Alpine gradient reveals importance of soil organic matter
The treeline is a demarcation point changing the patterns of CO2 and N2O fluxes across the elevational gradient, highlighting the importance of soil organic matter quantity and composition in controlling microbial enzyme activities and greenhouse gas fluxes.
The study revealed how soil organic matter properties influence soil microbial enzyme activities and greenhouse gas fluxes across the Alpine elevational gradient. Bacterial and fungal biomass increased from the low-altitudinal temperate forests to the subalpine forests near the tree line and decreased significantly from the tree line to the mountain summit. CO₂ fluxes exhibited a hump-shaped pattern along the elevational gradient, peaking in the subalpine forests near the tree line and decreasing significantly from the tree line to the summit.
Soil organic matter quantity and composition (humification index, i.e. the proportion of humic-like vs. protein-like organic matter) varied significantly across the gradient. Below the tree line, soil organic matter quantity and humification increased with elevation, while above the tree line, both decreased significantly. The humification index as well as fluorescence indices indicated a shift from plant-derived humic organic matter below the tree line to microbial-derived protein-like organic matter above the tree line. The study provides valuable insights into how soil organic matter properties and environmental factors drive microbial activities and greenhouse gas fluxes in mountain ecosystems.
Link to scientific paper: https://doi.org/10.1016/j.geoderma.2024.116993
Contact Professor Anders Priemé, Department of Biology, University of Copenhagen, aprieme@bio.ku.dk for more information.