Effect of Nutrient and Temperature Conditions on the Production of Microcystins From Cyanobacteria in Pineview Reservoir

Cyanobacteria, sometimes known as harmful algae, are an aquatic bacteria capable of producing toxic compounds. Cyanobacteria are found worldwide in both saltwater and freshwater environments. Depending on the environment, toxic cyanobacteria species can outcompete other aquatic species, grow in large numbers, and produce these toxic compounds. Further understanding of what environmental conditions promote the production of these harmful bacteria and toxins is needed to protect and inform the public. In order to understand why cyanobacteria produce toxins in certain environments, samples containing cyanobacteria were taken from a Pineview Reservoir, Utah, and cultured at the Utah State Water Research Laboratory. Cyanobacteria from these cultures were subjected to different nutrient concentrations (phosphorus and nitrogen) and water temperature (25ºC and 16ºC) conditions to test whether these conditions resulted in an increase in toxin production. Results from the experiments show that lowering water temperature, a low dissolved phosphorus concentration, and the dissolved N:P ratio did not increase the production of toxins during the experiments. Even though no increase in toxin production was seen in the environmental factors tested, it was seen that as total phosphorus concentrations increased so did microcystin concentration. It was also seen that as the total N:P ratio decreased an increase in toxin production was seen.