Cyanobacteria Abundance and Toxin Production in a Drinking Water Supply Reservoir

Cyanobacteria are prokaryotic organisms that live in marine and freshwater environments and are most common during the warmer months. Many cyanobacteria are also known to release toxins that target cellular processes and affect a wide range of organisms, including people. Although the effects of toxins on biodiversity have been documented, the main reason why cyanobacteria release their toxins is still unknown. This study examined the co-occurrence of cyanobacteria densities and hepatotoxin concentrations in a local drinking water reservoir. McDaniel Lake is a man-made reservoir located about 7 km north of Springfield, Missouri, and is used as a source of drinking water for the city. Two sites in McDaniel Lake (up-lake and near the dam) were sampled weekly on 26 dates from May 23 – September 16, 2011, to determine algal composition, particularly of cyanobacteria, and their corresponding densities over time. The presence and concentration of hepatotoxins were also measured using enzyme-linked immunosorbant assay (ELISA) kits. Over the period of the study, cyanobacteria density ranged from 0.04 - 3.3 x 104 units/mL and an invasive species (Cylindrospermopsis sp.) was detected. Despite occasional high concentrations of cyanobacteria and detectable taste and odor compounds, hepatotoxins were not detected on any date at either site