Continuous, short-interval redox data loggers: verification and setup considerations

Abstract

Reduction–oxidation or redox potential is typically collected by measuring redox at a single time interval and returning to the electrode to collect subsequent intervals to generate a temporal gradient of changes in redox. Typically, intervals between sampling are on the scale of hours, days, and weeks, rather than one, five, or 20 minutes due to logistical constraints of collection. These constraints are labor (i.e., constant measurements 24/7) and technology driven (i.e., construction of a unit that is capable of accurately and precisely measuring redox at fine temporal scales). This study describes a continuous, short interval redox data logger that is capable of measuring ±10 mV at minute time intervals. To ensure quality assured and quality controlled data, the redox unit was subjected to tiered verification procedures that documented hardware and probe sensitivity to changes in voltage. Furthermore, the setup was laboratory tested against known mV redox solutions (Zobel, 225 mV), flooded in soil medium over 48 h, and subjected to drying over 48 h. Results highlight and verify the accuracy and precision of the redox probes and hardware for measuring stability and changes in redox. Future research will investigate field operations of redox probes and create spatially and temporally detailed investigations to changes in redox as a result of vegetation, flooding, and management.