Carbon Dioxide Dynamics in Acid Forest Soils in Shenandoah National Park, Virginia

Carbonic acid, derived from soil CO 2 , may strongly affect stream‐water chemistry. The spatial and temporal variability of soil CO 2 levels was examined in the White Oak Run watershed of Shenandoah National Park, Virginia. This watershed is in a mountainous, forested region that is being studied to monitor the effects of atmospheric acidic deposition. Two soils—one comprised of alluvial infill on a valley bottom, the other covering a steep hillslope—were monitored for CO 2 levels and soil temperature and moisture. Carbon dioxide concentrations varied from atmospheric levels during the winter to nearly two orders of magnitude higher in late summer. There were strong correlations of CO 2 with soil air temperature, but correlations with soil moisture content were weak. The strong seasonal fluctuations of CO 2 may explain variations in White Oak Run stream‐water alkalinity and base‐cation concentrations.