Effects of the carotenoid inhibiting herbicide diflufenican on the photosynthesis of benthic algae

摘要: Throughout the world, large-scale use of pesticides in agriculture is an area concern due to known harmful effects on human and environmental health. Mixtures different are found lakes streams, where their presence endangers aquatic organisms, like benthic algae, ecosystem services they provide. Benthic algae important primary producers chemical modulators. Since photoautotrophs, especially threatened by photosynthesis inhibiting herbicides. Studies have shown that exposure herbicides causes toxic although most risk assessments performed planktonic algae. The aim this study was evaluate herbicide diflufenican (2',4'-difluoro-2-(α,α,α-trifluoro-m-tolyloxy)nicotinanilide) photosynthetic efficiency algal communities. choice based high prevalence above its water quality standard Swedish surface waters as well toxicity organisms. Diflufenican inhibits synthesis carotenoids weeds, which photo-bleaching green tissues oxidative degradation chlorophylls, main light-harvesting pigments. hypothesis would diminish community. conducted using grown for six weeks tiles submerged Lake Erken (59˚50’N, 18˚35’E). were then exposed twelve days. To throughout experiment, chlorophyll fluorescence measured with a Pulse Amplitude Modulated Fluorometer (PAM-FMS 1, Hansatech®). In contrast my expectations, highest test concentration (10 μg/L) increased level control. Interestingly, biomass did not seem differ between treatments These results indicate might induced more chlorophylls way increase energy attainment be able cope stress; mechanism called greening effect. However, does affect existing pool carotenoids, thus it only affects growing parts weeds. over course study, been sufficient, at least some This could explain lack difference lower Additionally, has also fatty acids plants. contributed effect despite growth. Further analysis will species composition pigment content, bring insights regarding community