Direct and indirect effects of the glyphosate formulation Glifosato Atanor on freshwater microbial communities

VERA MS; DI FIORI E; LAGOMARSINO L.; SINISTRO R.; ESCARAY R.; IUMMATO MM; JUÁREZ AB; RÍOS DE MOLINA MC; TELL GUILLERMO; PIZARRO H

ECOTOXICOLOGY

SPRINGER

Año: 2012 vol. 21 p. 1805 - 1816

0963-9292

Glyphosate-based formulations are among themost widely used herbicides in the world. The effect of theformulation Glifosato Atanor on freshwater microbialcommunities (phytoplankton, bacterioplankton, periphytonand zooplankton) was assessed through a manipulativeexperiment using six small outdoor microcosms of smallvolume. Three of the microcosms were added with3.5 mg l-1 of glyphosate whereas the other three were leftas controls without the herbicide. The treated microcosmsshowed a significant increase in total phosphorus, not fullyexplained by the glyphosate present in the Glifosato Atanor. Therefore, part of the phosphorus should have comefrom the surfactants of the formulation. The results showedsignificant direct and indirect effects of Glifosato Atanoron the microbial communities. A single application of theherbicide caused a fast increase both in the abundance ofbacterioplankton and planktonic picocyanobacteria and inchlorophyll a concentration in the water column. Althoughmetabolic alterations related to oxidative stress wereinduced in the periphyton community, the herbicidefavored its development, with a large contribution of filamentousalgae typical of nutrient-rich systems, with shallowand calm waters. An indirect effect of the herbicide onthe zooplankton was observed due to the increase in theabundance of the rotifer Lecane spp. as a consequence ofthe improved food availability given by picocyanobacteriaand bacteria. The formulation affected directly a fraction ofcopepods as a target. It was concluded that the GlifosatoAtanor accelerates the deterioration of the water quality,especially when considering small-volume water systems.