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| Titel |
Simulating soil atmosphere above a leaky CCS deposit |
| VerfasserIn |
Helmer Schack-Kirchner, Martin Maier |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250113543
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| Publikation (Nr.) |
 EGU/EGU2015-13757.pdf |
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| Zusammenfassung |
| The escape of CO2 at the surface above a leaky geological deposit of carbon dioxide can be a
fumarole-like point source or a subsurface plume distributing the gas over a larger area. In the
latter case the lost CO2 from the deposit is added to the soil respiration as a quasi
one-dimensional non-equimolar gas flux. Whether such an additional flux leads
to inhibitory high levels of soil CO2 combined with a rather complete advective
displacement of O2 or simply changes the diffusion characteristics in a more or less
normal soil atmosphere depends for a given gas diffusivity and permeability on
the ratio between the equimolar (respiratory) and the non-equimolar (leak based)
flux of CO2. We tested the effecs by parametrization of a conceptual soil model
consisting of capillaries filled either with soil air or water joining the soil air and the
above-ground atmosphere. Soil atmosphere was simulated by combining a numerical
solution of the Dusty-Gas model and a simple gas diffusion model in the water
filled capillaries in an iterative process until Argon as noble gas is stagnant. The
results show that in soils with high gas permeability even non-equimolar CO2
fluxes more than twice the soil respiration can be transferred to the surface without
spectacular changes in soil-air pressure or O2 displacement. However, even low
extra CO2 fluxes change significantly the gradient ratio of O2 and CO2 and stress
soil aeration which is for many forest ecosystems a limiting factor of root growth. |
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