Carbon dioxide retention and carbon exchange on unsaturated Quaternary sediments
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.
Citation Information
Publication Year | 1990 |
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Title | Carbon dioxide retention and carbon exchange on unsaturated Quaternary sediments |
DOI | 10.1016/0016-7037(90)90051-L |
Authors | Robert G. Striegl, D.E. Armstrong |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Geochimica et Cosmochimica Acta |
Index ID | 70015980 |
Record Source | USGS Publications Warehouse |
USGS Organization | Coop Res Unit Seattle |