Phycocyanin sensors as an early warning system for cyanobacteria blooms concentrations: a case study in the Rotorua lakes

Cyanobacterial blooms pose health risks to recreational water users. In New Zealand, cyanobacteria biovolumes are used to assess risk, but analyses can be time-consuming and costly. In this study, measurements from a handheld phycocyanin sensor (Cyclops-7, Turner Designs, USA) were compared with biovolumes from five lakes and a river in the Rotorua district over two years (2016, n = 121; 2017, n = 63). In the laboratory, relationships between sensor phycocyanin and biovolumes were assessed for four species to investigate precision and detection limits. The relationship between phycocyanin and biovolume was generally weak (