The effects of atrazine on Douglas Lake periphyton.

Abstract

The purpose of this experiment is to study the effects of different concentrations of atrazine on the growth of Douglas Lake periphyton. Atrazine is one of the most widely used herbicides today and therefore will have a significant impact on the ecology of freshwater systems. Its danger to freshwater systems arises from the agricultural runoff of surrounding areas into nearby lakes. A study by Herman, et al. (1986), showed that a 100 mu g/l concentration of atrazine resulted in a significant decrease in organic matter, chlorophyll, and algal biomass. In addition, community structure was altered signficantly, yielding a decrease in blue green algae, an increase in diatoms, and a change in the species composition of green algae. Since atrazine is an herbicide, I expect it to decrease net algal growth, as measured by the number of cells growing on a known area of an artificial substrate.