Development of a flow-through fluorometric system for the detection of phycocyanin in the lower Great Lakes

Cyanobacterial blooms are an important concern in the Great Lakes. These blooms vary in their spatial and temporal distribution and this patchiness makes monitoring blooms in large bodies of water difficult. We have developed a fluorometric system for continuous monitoring of cyanobacterial blooms using the in situ fluorescence of the pigments phycocyanin and chlorophyll. A simple method for extracting phycocyanin from Microcystis aeruginosa and Anabaena species was developed and the optimal excitation and emission wavelengths for this pigment determined. Three different fluorometers (Hydrolab, YSI, and 10-AU) were compared and deployed onboard the CCGS Limnos in 2004 and 2005. Precalibration of the pigment sensors prior to ship deployment was unsuccessful, however pigment concentrations were obtained using a calibration curve generated from samples taken at predetermined stations. Limitations to the accuracy of these fluorometric systems were discussed along with their use for continuous monitoring of cyanobacterial blooms in the lower Great Lakes.