Sensor data as a measure of native freshwater mussel impact on nitrate formation and food digestion in continuous-flow mesocosms

AbstractNative freshwater mussels can influence the aquatic N cycle, but the mechanisms and magnitude of this effect are not fully understood. We assessed the effects of Amblema plicata and Lampsilis cardium on N transformations over 72 d in 4 continuous-flow mesocosms, with 2 replicates of 2 treatments (mesocosms with and without mussels), equipped with electronic water-chemistry sensors. We compared sensor data to discrete sample data to assess the effect of additional sensor measurements on the ability to detect mussel-related effects on NO3– formation. Analysis of 624 sensor-based data points detected a nearly 6% increase in NO3– concentration in overlying water of mesocosms with mussels relative to mesocosms without mussels (p < 0.05), whereas analysis of 36 discrete samples showed no statistical difference in NO3– between treatments. Mussels also significantly increased NO2– concentrations in the overlying water, but no significant difference in total N was observed. We used the sensor data for phyt...