CARBON DIOXIDE DYNAMICS AT THE SAVOY EXPERIMENTAL WATERSHED

The importance of carbon cycling in karst terrains within the global carbon cycle is uncertain. However, it is known that carbon dioxide dynamics play a key role in determining the spatial and temporal distributions of dissolution and precipitation of carbonates. We explore these dynamics within a mantled karst terrain in Northwest Arkansas. Concentrations of dissolved carbon dioxide have been measured for two years at two springs (Copperhead and Langle) at the Savoy Experimental Watershed east of Fayetteville, AR. Ongoing research at Savoy has made this a well-characterized local karst site, but is lacking research involving spatial variability of CO2. This project aims to expand this work and to better constrain carbon budgets within the system. To better constrain the sources of CO2 within the system, we have instrumented two additional sites, at a sinking stream that feeds Copperhead and Langle Springs, and an epikarst spring that feeds the sinking stream. Additionally, a weather station has been deployed within the basin to enable observation of seasonal and diurnal temperature changes, storm events, and soil moisture and to examine what impact these parameters have on CO2 concentrations. Soil CO2 flux measurements taken throughout the year will also be compared against these data. Flux will be compared before and after storms, within and below the epikarst, and at pastured and forested locations. This combination of dissolved CO2, weather, and soil CO2 flux data will contribute to understanding of spatial and temporal variability in CO2, and the role that karst plays in the global carbon cycle.