Kimberly Lowder, Weber State University
The herbicide Roundup and its active ingredient, Glyphosate, are widely used for weed control. These chemicals end up into streams and lakes, including the Great Salt Lake where it adversely affects wildlife. The goals of this project are a) to assess the mortality rate of Artemia larvae exposed to various concentrations of Roundup concentrate after a short exposure (48h) or a long-chronic exposure (7 days), b) to assess the effect of chronic on survival, maturation and fertility and c) to quantify the stress response of the shrimp on the heat-shock proteins 90 and 70. Materials and Methods: For the acute exposure, Artemia larval mortality was calculated in larvae exposed to Roundup concentrations ranging from 10-3 to 10-10 ml/l of Roundup concentrate for 48 h. For the chronic exposure, larvae were raised in the above Roundup concentrations. Mortality, maturation and fertility rates were calculated. The response to stress was assessed by quantifying the up-regulation of stress proteins hsp90 and 70 using western blots. Results: All larvae were killed after exposure at 10-4 g/l or greater of Roundup concentrate. Most larvae survived at Roundup concentrations of 10-6 ml/l or less. While chronic exposure to lower Roundup concentrations did not seem to affect survival or maturation rate, it did affect larval development. Larvae developing in 10-7 ml/l or more Roundup had about a 20% risk of not hatching or dying shortly after hatching. Hsp70 western blots showed an upregulation of this heat-shock protein at 10-5 ml/l or higher Roundup concentrations.