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| Titel |
Intra-aggregate CO2 enrichment: a modelling approach for aerobic soils |
| VerfasserIn |
D. Schlotter, H. Schack-Kirchner |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 2 ; Nr. 10, no. 2 (2013-02-25), S.1209-1218 |
| Datensatznummer |
250018117
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| Publikation (Nr.) |
 copernicus.org/bg-10-1209-2013.pdf |
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| Zusammenfassung |
| CO2 concentration gradients inside soil aggregates, caused by the
respiration of soil microorganisms and fungal hyphae, might lead to
variations in the soil solution chemistry on a mm-scale, and to an
underestimation of the CO2 storage. But, up to now, there seems to be no
feasible method for measuring CO2 inside natural aggregates with
sufficient spatial resolution. We combined a one-dimensional model for gas
diffusion in the inter-aggregate pore space with a cylinder diffusion model,
simulating the consumption/production and diffusion of O2 and CO2
inside soil aggregates with air- and water-filled pores. Our model predicts
that for aerobic respiration (respiratory quotient = 1) the intra-aggregate
increase in the CO2 partial pressure can never be higher than 0.9 kPa
for siliceous, and 0.1 kPa for calcaric aggregates, independent of the level
of water-saturation. This suggests that only for siliceous aggregates
CO2 produced by aerobic respiration might cause a high small-scale
spatial variability in the soil solution chemistry. In calcaric aggregates,
however, the contribution of carbonate species to the CO2 transport
should lead to secondary carbonates on the aggregate surfaces. As regards the
total CO2 storage in aerobic soils, both siliceous and calcaric, the
effect of intra-aggregate CO2 gradients seems to be negligible. To
assess the effect of anaerobic respiration on the intra-aggregate CO2
gradients, the development of a device for measuring CO2 on a mm-scale
in soils is indispensable. |
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