THE IMPORTANCE OF EXAMINING THE WHOLE PHYTOBENTHIC COMMUNITY IN HERBICIDE EXPOSURE STUDIES

Abstract

Pesticides are commonly used in agricultural practices, and their residues can enter freshwater bodies potentially posing a threat to the aquatic ecosystem. This study investigated the short-term effects of glyphosate and chlorotoluron herbicides on riverine phytobenthic biofilms, which are major primary producers in freshwater. The biofilms were exposed to the herbicides using outdoor flumes to imitate field exposures. Results indicated a significant decrease in biomass and rates of areal gross maximum photosynthesis in flumes treated with glyphosate and glyphosate/chlorotoluron mixture. The study also observed benthic diatom development along different trajectories following the herbicide treatment. However, after 4.5 days, biomass concentrations were similar in all controls and treatments, indicating biofilm recovery in the glyphosate-based herbicide and glyphosate/chlorotoluron treated biofilms. This study emphasizes the significance of phytobenthic communities in herbicide impact assessment and suggests that assessment tools based on phytobenthos may require adjustment to consider herbicide-specific responses of the community. The findings of this study have implications for the ecological status evaluation of freshwater bodies