EGU2020-17686
https://doi.org/10.5194/egusphere-egu2020-17686
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

The effect of vertical distribution functions on CO2 efflux and production calculated with the flux gradient approach

Hubert Jochheim1, Stephan Wirth1, Sinikka Paulus2, Martin Maier3, Christoph Haas1, and Horst H. Gerke1
Hubert Jochheim et al.
  • 1Leibniz Centre for Agricultural Landscape Research (ZALF), Research Platform Models & Simulation, Müncheberg, Germany (hjochheim@zalf.de)
  • 2Max Planck Institute for Biogeochemistry, Jena, Germany
  • 3Forest Research Institute Baden Württemberg (FVA), Freiburg, Germany

Soil respiration is one of the most significant carbon fluxes in terrestrial ecosystems. The analyses and quantification of soil CO2 production and its influencing factors play a crucial role in the understanding of the global carbon budget.

To investigate CO2 efflux from terrestrial soils under field conditions, manual or automated soil chambers are the most common methods. The flux-gradient approach (FGA) as an alternative method applies Fick’s law to vertical profiles of soil CO2. The FGA uses the soil gas diffusivity to calculate vertical fluxes of soil CO2 and the CO2 efflux from soil. The vertical partitioning the production of CO2 in different soil layers can be regarded as an option and an advantage of FGA as compared to chamber methods.

This investigation aims at clarifying whether a spline or an exponential function is more suitable for fitting vertical distributions of measured CO2 concentrations. We compared simulation results on the CO2 efflux and the vertical distribution of CO2 production within the soil when applying an exponential function or a spline function, respectively. Soil CO2 concentrations were measured at the soil surface and at 0, 0.1, 0.2, 0.3 and 1.0 m soil depth of a Scots pine and a European beech forest stand of the Northeast German Lowlands. Additionally, the CO2 efflux was estimated by applying the manual chamber method. The results suggest that vertical distribution function of soil CO2 affects both the calculated CO2 efflux and the production of soil CO2. The CO2 efflux from the chamber method fits best with the CO2 efflux from spline function. We discus some effects with the application of the spline function on the calculated vertical distribution of CO2 production.

How to cite: Jochheim, H., Wirth, S., Paulus, S., Maier, M., Haas, C., and Gerke, H. H.: The effect of vertical distribution functions on CO2 efflux and production calculated with the flux gradient approach, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17686, https://doi.org/10.5194/egusphere-egu2020-17686, 2020

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