Roundup® (glyphosate formulation) effects on freshwater periphyton: experimental approach using mesocosms

PIZARRO, HAYDÉE; VERA, M. S.; SYLVESTER, M.; BUSTINGORRY, J.; ESCARAY, R.; FERRARO, M.; PÉREZ, G.; RODRÍGUEZ, PATRICIA; MUGNI, H.; BONETTO, C.; ZAGARESE, H.

St. John's, Newfoundland, Canadá

Congreso; 2008 ASLO Summer Meeting, Interactions on the Edge, St. John's, Newfoundland, Canadá, 8-13 Junio 2008; 2008

American Society of Limnology and Oceanography (ASLO)

Glyphosate formulation (Roundup®) effects on periphyton community were studied by means of six experimental mesocosms (25m2 x 1m): three were treated with 6 mg l-1 of Roundup® and 3 were considered control (without herbicide). Artificial substrates were used in each mesocosm for periphyton colonization and collected 8, 14, 20 and 34 days after addition. Dry weight, ash-free dry weigth, chlorophyll a, primary production as well taxonomic composition and density of live and dead algae were analised. All periphytic variables for treated mesocosms showed lower values during the entire experiment (p<0.05; MannWhitney test). Significant differences (p<0.05; Friedman test) were detected among sampling dates for variables at control mesocosms but not always for the treated ones. In mesocosms with Roundup® algal composition turned to the increase of cyanobacteria while density of dead algae was significantly higher (p<0.05, MannWhitney test). The observed changes in the structure and functionality of periphyton are consistent with the direct toxicological effect of glyphosate formulation which implies a clear impact in the whole ecology of the system due to periphyton is an important component of aquatic food webs.