Title: Carbon dioxide retention and carbon exchange on unsaturated Quaternary sediments
Abstract: Retention of CO2 on three air-dried and partly water-saturated glacial and eolian sediments was measured at 20°C for a range in, PCO2 that commonly occurs in unsaturated zones. Ratios of the relative losses of CO2 and 14CO2 from a surrogate atmosphere overlying the sediments were 1:1 for the dry condition. For the wet condition, those relative losses were generally ⪯ 1:2, indicating bicarbonateion formation and C-isotope exchange. Mass losses of CO2 per surface area of sediment were similar for dry and wet conditions; however, CO2 losses for the wet condition were 8 to 17 times greater than losses predicted by calcite equilibria. Occurrence of this comparatively large reservoir of immobile, exchangeable C in unsaturated zones can cause alteration of the C-isotope composition of soil CO2 and of dissolved inorganic C in interstitial water, and needs to be considered when modeling 14CO2 movement in the unsaturated zone or when interpreting radiocarbon ages of infiltrating water.
Publication Year: 1990
Publication Date: 1990-08-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 23
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