Michelle Le

Document Type

Honors Thesis


Water pollution is a worldwide concern due to its devastating effects on the environment. Not only does this pose a significant threat to the environment, but these effects can also matriculate to humans causing disease and even death. As clean water is vital to our society, it is essential to monitor the effects of pollution and assess water quality. Using Daphnia spp. as bioindicators, the effects of various sublethal doses of ammonia, a common waterborne pollutant, on the phototactic behavior of Daphnia was investigated. Daphnids were first reared in common garden conditions and exposed to following concentrations of ammonia: 0 μL, 7 μL, 10.5 μL, 14 μL, and 17.5 μL (in proportion to 90 mL of COMBO media). After continuous and post-ammonia exposure, daphnids were placed in 500 mL vertical columns under dark conditions for five minutes. The phototactic indices were calculated using the number of daphnids found in either the top, middle, or bottom region of the vertical column. Overall, it was found that high concentrations of ammonia significantly disrupted the behavior of Daphnia, with Daphnia exhibiting significantly more positive phototactic behavior.

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