Carbon dioxide and dissolution rate dynamics within a karst underflow-overflow system, Savoy Experimental Watershed, Arkansas, USA

摘要: Abstract Within numerical models of karst development, geochemical and hydrological boundary conditions are typically assumed to be constant. However, rates calcite dissolution in natural systems can vary substantially time. In particular, variation carbon dioxide (CO2) concentrations has been shown produce time variability streams, but controls on CO2 within relatively poorly quantified. Here we analyze hourly in-situ measurements dissolved CO2, discharge, specific conductance at a pair underflow-overflow springs examine potential drivers rates. The display strong seasonal saturation state as well moderate during storm events. Though both have elevated the summer season, overflow spring experiences substantial decrease below critical discharge threshold. We hypothesize that this results from ventilation portion system segments flow path transition full pipe open channel flow. lower average than underflow spring, despite larger chemical high events spring. frequently presumed higher rates, because their ability replenish is consumed process, these data suggest closed may some cases due inability paths ventilate excess atmosphere. Such likely occur conduits where above atmospheric levels through times short compared scale over which water reaches equilibrium with respect calcite.