3. Results
3.1. Water physico–chemical parameters and chlorophyll A
Continuous temperature and DO measurements at 10 and 40 cm depth below the FTW were relatively similar with an absolute median difference of 0.2 °C (25th-75th percentile: 0.1–0.4) and 0.7 mg/L (25th-75th percentile: 0.2–1.5), respectively, between readings at 10 and 40 cm taken at the same time (Fig. 2). Therefore only the measurement at 10 cm depth presenting the greatest amount of recorded data in the FTW pond was used for comparison with the continuous monitoring in the Control pond.
Continuous monitoring reveals that mean daily DO in the FTW pond was on average 9.2 mg/L (std.dev. 3.5) lower than in the Control pond. DO variability was greater in the Control pond with an average daily variation of 5.7 mg/L (std.dev. 3.1) compared to 2.5 mg/L (std.dev. 1.7) in the FTW pond. During summer the FTW pond exhibited the lowest DO concentration, with an average of 0.9 mg/L (std. dev. 1.5) (Fig. 2). Periodic monitoring confirms that the FTW reduced water column DO similarly throughout the year