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Intra-aggregate CO2 enrichment: a modelling approach for aerobic soils.
- Source :
- Biogeosciences Discussions; 2012, Vol. 9 Issue 10, p14795-14822, 28p
- Publication Year :
- 2012
-
Abstract
- CO<subscript>2</subscript> 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 CO<subscript>2</subscript> storage. But, up to now, there seems to be no feasible method for measuring CO<subscript>2</subscript> 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 O<subscript>2</subscript> and CO<subscript>2</subscript> inside soil aggregates with airand water-filled pores. Our model predicts that for aerobic respiration (respiratory quotient= 1) the intra-aggregate increase in the CO<subscript>2</subscript> partial pressure can never be higher than 0.9 kPa for siliceous, and 0.08 kPa for calcaric aggregates, independent of the level of water-saturation. This suggests that only for siliceous aggregates CO<subscript>2</subscript> 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 CO<subscript>2</subscript> transport should lead to secondary carbonates on the aggregate surfaces. As regards the total CO<subscript>2</subscript> storage in aerobic soils, both siliceous and calcaric, the effect of intra-aggregate CO<subscript>2</subscript> gradients seems to be negligible. To assess the effect of anaerobic respiration on the intra-aggregate CO<subscript>2</subscript> gradients, the development of a device for measuring CO<subscript>2</subscript> on a mm-scale in soils is indispensable. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 18106277
- Volume :
- 9
- Issue :
- 10
- Database :
- Complementary Index
- Journal :
- Biogeosciences Discussions
- Publication Type :
- Academic Journal
- Accession number :
- 83302065
- Full Text :
- https://doi.org/10.5194/bgd-9-14795-2012