The effect of temperature and a herbicide mixture on freshwater periphytic algae

• Published in: Ecotoxicology and environmental safety 2013-12, Vol.98, p.162-170
• Main Authors: Larras, Floriane, Lambert, Anne-Sophie, Pesce, Stéphane, Rimet, Frédéric, Bouchez, Agnès, Montuelle, Bernard
• Format: Article
• Language: English
• Subjects: acclimation; Algae; Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; aquatic environment; atrazine; Atrazine - toxicity; biofilm; Biofilms; Biological and medical sciences; Diatoms - drug effects; diuron; Diuron - toxicity; Ecotoxicology, biological effects of pollution; environmental factors; Environmental Sciences; Fresh Water; Fresh water ecosystems; Fresh water environment; freshwater; Fundamental and applied biological sciences. Psychology; Herbicides; Herbicides - toxicity; isoproturon; littoral zone; microalgae; Mixture; Periphytic algae; Phenylurea Compounds - toxicity; Synecology; Temperature; terbutryn; toxicity; Triazines - toxicity
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2013.09.007

Temperature is a strong driver of biofilm formation and of the dynamics of microalgae in freshwater. Moreover, exposure to herbicides is a well-known stressor of periphytic communities in anthropized aquatic environments. We tested these two environmental factors on periphytic communities that had been sampled from the littoral zone of Lake Geneva and acclimatized in the lab for 3 weeks at 18, 21, 24 and 28°C. After this acclimation period, differences in the composition of the diatom community and decreases in cell density were observed corresponding to the temperature gradient. These acclimated communities were then exposed to 23 and 140nM of a mixture composed of equitoxic quantities of atrazine, terbutryn, diuron and isoproturon. The periphytic community was more sensitive to the herbicide mixture at 18°C than at higher temperatures, suggesting that higher temperature reduced its toxicity. Small and pioneer diatom species known to be promoted by contamination also appeared to benefit from higher temperatures. Temperature therefore appears to condition the herbicide sensitivity of periphytic communities. •Temperature influences algal community structure and dynamic.•Sensitivity of algal community to herbicides is influenced by growth temperature.•Higher temperatures and herbicides concentrations select smaller diatoms species.