Assessing spatial distributions of cyanobacteria and microcystins in N.H. lakes with implications for lake monitoring

Cyanobacteria pose a threat to the health of humans and wildlife when concentrations are high and the species present are toxic. However, routine monitoring of toxic cyanobacteria in lakes is not typical in the United States and, currently, there are no standards on the allowable limit of cyanotoxins in N.H. water bodies. Phycocyanin (PC) fluorescence was evaluated as an indicator for cyanobacteria densities, with implications for monitoring cyanobacteria and microcystins in lakes. PC fluorescence predicted cultured cyanobacteria, ranging from 0--900,000 cells ml-1 (Adj R 2 0.99, p<0.001). PC fluorescence was also useful for estimating microcystin (MC) concentrations among lakes of varying trophic status (p<0.001) and was more significant than net cyanobacteria counts were for predicting microcystin concentrations (p=0.049). Synoptic, horizontal sampling revealed the significant variability in the spatial distributions of cyanobacteria and microcystins in N.H. lakes.