Cyanobacterial Bloom Risk Assessment of Pontoosuc Lake

Cyanobacterial blooms can be toxic to human and animal health. The purpose of this study was to examine temperature, dissolved oxygen, zooplankton density, and nutrient level data which influence algal succession patterns and determine if Pontoosuc Lake is at risk for a cyanobacteria bloom. We expected that the lake’s biological and physical characteristics would moderately support a cyanobacterial bloom due to the heavy development around the shoreline and probable commercial and residential use of synthetic fertilizers on adjacent parcels. As such, we hypothesized that N:P ratios would be less than the threshold of 7:1, supporting the possibility of a cyanobacteria bloom. The data supported the hypothesis, showing that total nitrogen to phosphorous ratio (N:P) is 6.125:1 in the epilimnion and 14.15:1 in the hypolimnion, which is within the threshold for cyanobacterial bloom risk.