The effects of atrazine on periphyton communities in controlled laboratory ecosystems

An aquatic microcosm study was designed to evaluate the direct and indirect effects of a 14 day, 100 μg atrazine/L exposure on periphyton community functional and structural parameters and to determine the recovery rates of these parameters after removing the atrazine input. Direct and indirect effects were evidenced by an immediate and continual decrease in net productivity and by significantly reduced algal densities, decreased diversity, altered species composition and reduced biomass accumulation. There were substantial differences in community recovery rates with net productivity returning to control values within 16 days while little recovery in community structural parameters occurred within the 21-day time period examined.