Impact of diuron and S-metolachlor on the freshwater diatom Gomphonema gracile: Complementarity between fatty acid profiles and different kinds of ecotoxicological impact-endpoints

Impact du diuron et du S-métolachlore sur la diatomée d'eau douce Gomphonema gracile : Complémentarité entre profils d'acides gras et différents types d'indicateurs écotoxicologiques

F. Demailly (1) , I. Elfeky (1) , L. Malbezin (2) , M. Le Guédard (3) , M. Eon (1) , J.J. Bessoule (4) , A. Feurtet Mazel (2) , François Delmas (1) , Nicolas Mazzella (1) , P. Gonzalez (2) , Soizic Morin (1)

1 UR EABX - Ecosystèmes aquatiques et changements globaux
2 EPOC - Environnements et Paléoenvironnements OCéaniques
3 LEB Aquitaine Transfert-ADERA
4 LBM - Laboratoire de biogenèse membranaire

Fatty acids (FA) are crucial for the maintenance of membrane fluidity and play a central role in metabolic energy storage. Polyunsaturated fatty acids play an essential ecological role since they are key parameters in the nutritional value of algae. Pesticide impacts on fatty acid profiles have been documented in marine microalgae, but remain understudied in freshwater diatoms. The aims of this study were to: 1) investigate the impact of diuron and S-metolachlor on "classical descriptors" (photosynthesis, growth rate, pigment contents, and on the expression levels of target genes in freshwater diatoms), 2) examine the impact of these pesticides on diatom fatty acid profiles and finally, 3) compare fatty acid profiles and "classical descriptor" responses in order to evaluate their complementarity and ecological role. To address this issue, the model freshwater diatom Gomphonema gracile was exposed during seven days to diuron and S-metolachlor at 10 µg.L.

Mots clés: freshwater; diuron; fatty acids; diatom; ecotoxicology

Mots clés: ECOTOXICOLOGIE; EAU DOUCE; DIATOMEE; ACIDE GRAS; DIURON

Domaines: Sciences de l'environnement

F. Demailly, I. Elfeky, L. Malbezin, M. Le Guédard, M. Eon, et al.. Impact of diuron and S-metolachlor on the freshwater diatom Gomphonema gracile: Complementarity between fatty acid profiles and different kinds of ecotoxicological impact-endpoints. Science of the Total Environment, 2019, 688, pp.960-969. ⟨10.1016/j.scitotenv.2019.06.347⟩. ⟨hal-02269682⟩