Around the world, levels of copper in aquatic ecosystems are rising due to agricultural and industrial practices and water treatment. Copper is highly toxic to many living organisms in aquatic ecosystems because it causes oxidative stress. Planaria are found on the surface of most freshwater ecosystems. It has been found that high levels of copper do not affect planaria mortality rates. Although the effect of copper on the mortality rate of planaria has been tested, the effect of copper on the regeneration of planaria has not been tested. Dugesia Dorotocephala are large, brown planaria. They are capable of reproducing sexually and asexually. Dugesia Dorotocephala are hermaphrodites, so every organism has both male and female reproductive organs. Sexual reproduction tends to occur at lower temperatures (about 20 degrees Celsius) and asexual reproduction, or fission, tends to occur at higher temperatures (about 26 degrees Celsius). Each organism is able to mate and reproduce multiple times in its lifetime.

1 hypothesize that if I expose Dugesia Dorotocephala to solutions of CuSO4-5H20, then the copper will inhibit the regeneration of the planaria, and the planaria exposed to higher concentrations will regenerate less than planaria exposed to lower concentrations.

In the experiment, there were five different experimental groups. The control group (Group 1) received spring water. Group 2 received 2 mg/L solution of cupric sulfate. Group 3 received 1.5 mg/L solution of cupric sulfate. Group 4 received 1 mg/L solution of cupric sulfate. Group 5 received 0.5 mg/L solution of cupric sulfate. Each group consisted of 6 petri dishes each with one planaria that was cut in half horizontally with a blade. The location of the cut on each organism was white in color, contrasting the dark color of the rest of the body. After one week, the number of organisms living, dead, and regenerated were counted. A regenerated planaria was considered to be a planaria where the location of the cut shows qualitative growth of the dark ectoderm (and is no longer white).

Trial 1 of the regeneration experiment found that cupric ions significantly affect the regeneration of planaria. Trials 2 and 3 were conducted during the months of February and March, which are during the planarias' sexual reproduction period. They were also conducted during warmer weather. Fission occurred during trials 2 and 3, producing new organisms in all solutions. The death rate dropped from trial one, and the percent of planaria regeneration in planaria exposed to cupric ions in trials 2 and 3 as compared to trial 1. This suggests that the planaria were better protected from toxic, cupric sulfate during trials 2 and 3. The planaria in trial 3, which were not significantly affected by the cupric sulfate, were used to conduct the catalase assay. The results from this assay were not statistically significant, which would be expected considering the planarias' regeneration was not significantly affected by the cupric sulfate.