Interrelationships of CO2, CH4, and N2O fluxes in snow-covered temperate soils, Northern Japan

Abstract

This study focuses on assessing the concentrations, fluxes, and production rates of greenhouse gases (CO₂, CH₄, and N₂O) in a cold temperate grassland soil underlying snowpack during the winter of 1996/7 in northern Japan. Results included mean ± standard deviation (range) correlation coefficients (R²) for CO₂–CH₄ concentrations and CO₂–N₂O concentrations of 0.93 ± 0.07 (0.81–0.99) and 0.96 ± 0.06 (0.83–0.99) for winter, and 0.74 ± 0.17 (0.55–0.92) and 0.96 ± 0.05 (0.88–0.99) for summer, respectively. This suggests close relationships between the mechanisms of CO₂ and N₂O production and the oxidation of CH₄, which are influenced by factors such as oxygen availability, temperature, and moisture in the soil. Furthermore, the study found that winter fluxes of CO₂–CH₄ and CO₂–N₂O through the snowpack showed positive linear correlations. Winter CO₂ emissions accounted for 96 % of the variability in CH₄ oxidation and 77 % of the variability in N₂O emissions. This demonstrates that winter CO₂ emissions were affected to the magnitude of CH₄ oxidations and N₂O emissions in the soil. These findings have implications for the modification of terrestrial ecosystem models in temperate regions, particularly in assessing contributions from winter greenhouse gas fluxes to overall annual emissions. Understanding the interrelationships and dynamics of greenhouse gases throughout the year is crucial for accurate modeling and predictions of ecosystem responses to climate change.