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Modeling the effects of gas phase CO 2 intrusion on the biogeochemistry of variably saturated soils
Author(s) -
Altevogt Andrew S.,
Jaffe Peter R.
Publication year - 2005
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2004wr003819
Subject(s) - biogeochemistry , biogeochemical cycle , soil water , carbon dioxide , soil science , environmental chemistry , soil gas , porous medium , environmental science , chemistry , geology , hydrology (agriculture) , porosity , geotechnical engineering , organic chemistry
The transport of gas phase carbon dioxide through unsaturated soils has the potential to significantly alter the soil biogeochemistry. Leakage of CO 2 from deep reservoirs, either naturally occurring or anthropogenically emplaced, may displace oxygen in the soil gas and hence radically alter the redox conditions of a soil. Furthermore, the formation of carbonic acid in the aqueous phase will alter the pH of the soil system. A two‐dimensional numerical model has been developed to explore the effects of gaseous CO 2 leakage on the biogeochemistry of a variably saturated porous media. The model describes the sequential degradation of organic carbon by microorganisms using a series of terminal electron acceptors. Gas phase CO 2 intrusion results in changes in redox conditions and pH of the soil water, both of which lead to alteration of the biogeochemistry of the soil. Alteration of the biogeochemical profile of a representative field site is explored with the numerical model.