Glyphosate input modifies microbial community structure in clear and turbid freshwater systems

• Published in: Environmental science and pollution research international Vol. 23; no. 6; pp. 5143 - 5153
• Main Authors: Pizarro, H, Vera, M. S, Vinocur, A, Pérez, G, Ferraro, M, Menéndez Helman, R. J, dos Santos Afonso, M
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-03-2016; Springer Nature B.V
• Subjects: adverse effects; Agriculture; Agrochemicals; Aquatic ecosystems; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; bacteria; Bacteria - drug effects; bacterioplankton; Chemical properties; Chlorophyll; Chlorophyll A; Community structure; Cyanobacteria; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental effects; Environmental Health; Environmental science; Eutrophic environments; Eutrophication; Experiments; Fresh Water - chemistry; Fresh Water - microbiology; freshwater; Freshwater resources; Glycine - analogs & derivatives; Glycine - pharmacology; Glyphosate; Herbicides; Herbicides - pharmacology; microbial communities; Microorganisms; phosphorus; physicochemical properties; Phytoplankton; Phytoplankton - drug effects; Plankton; Research Article; Studies; surface water; trophic relationships; Trophic status; Turbidity; Waste Water Technology; Water bodies; Water Management; Water Microbiology; Water Pollutants, Chemical - pharmacology; Water Pollution Control; Water properties; Microbial structure; Mesocosms; Organic turbidity; Picocyanobacteria; Trophic status; Freshwater ecosystems; Herbicide
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-015-5748-0

Since it was commercially introduced in 1974, glyphosate has been one of the most commonly used herbicides in agriculture worldwide, and there is growing concern about its adverse effects on the environment. Assuming that glyphosate may increase the organic turbidity of water bodies, we evaluated the effect of a single application of 2.4 ± 0.1 mg l⁻¹ of glyphosate (technical grade) on freshwater bacterioplankton and phytoplankton (pico, micro, and nanophytoplankton) and on the physical and chemical properties of the water. We used outdoor experimental mesocosms under clear and oligotrophic (phytoplanktonic chlorophyll a = 2.04 μg l⁻¹; turbidity = 2.0 NTU) and organic turbid and eutrophic (phytoplanktonic chlorophyll a = 50.3 μg l⁻¹; turbidity = 16.0 NTU) scenarios. Samplings were conducted at the beginning of the experiment and at 1, 8, 19, and 33 days after glyphosate addition. For both typologies, the herbicide affected the abiotic water properties (with a marked increase in total phosphorus), but it did not affect the structure of micro and nanophytoplankton. In clear waters, glyphosate treatment induced a trend toward higher bacteria and picoeukaryotes abundances, while there was a 2 to 2.5-fold increase in picocyanobacteria number. In turbid waters, without picoeukaryotes at the beginning of the experiment, glyphosate decreased bacteria abundance but increased the number of picocyanobacteria, suggesting a direct favorable effect. Moreover, our results show that the impact of the herbicide was observed in microorganisms from both oligo and eutrophic conditions, indicating that the impact would be independent of the trophic status of the water body.