Storm pulses of dissolved CO₂ in a forested headwater Amazonian stream explored using hydrograph separation

Dissolved CO 2 dynamics in stormflow and event water versus preevent water contributions to storm hydrographs were assessed in a forested headwater catchment of the Brazilian Amazon using high‐frequency data. We applied the transfer function hydrograph separation model (TRANSEP) using specific conductance as a conservative tracer, finding preevent water to average 0.79 ± 0.03 of storm discharge (mean ± 1 SE for n = 14 storms). In situ, direct measurements of dissolved CO 2 were able to capture new hydrobiogeochemical processes in real time, including CO 2 pulses observed on the falling limb of storm hydrographs, the magnitudes of which were inversely related to preevent water fractions ( r = −0.97, p < 0.0001).