Biologist ‘shocked’ to see morphological changes in vertebrates
By Summit Voice
SUMMIT COUNTY — Exposure to sub-lethal doses of a widely used weed killer caused tadpoles to grow abnormally large tales, according to University of Pittsburgh biologist Rick Relyea, who has been studying ecotoxicology and ecology for two decades.
Relyea has conducted extensive research on the toxicity of Roundup® to amphibians. Monsanto has challenged some of the studies and Relyea has responded to the criticism on this website.
In his latest study, Relyea set up large outdoor water tanks that contained many of the components of natural wetlands. Some tanks contained caged predators, which emit chemicals that naturally induce changes in tadpole morphology (such as larger tails to better escape predators). After adding tadpoles to each tank, he exposed them to a range of Roundup® concentrations. After 3 weeks, the tadpoles were removed from the tanks.
“It was not surprising to see that the smell of predators in the water induced larger tadpole tails,” Relyea said. “That is a normal, adaptive response. What shocked us was that the Roundup® induced the same changes. Moreover, the combination of predators and Roundup® caused the tail changes to be twice as large.” (more…)