Daphnia magna are found in freshwater environments, and are a part of the Phyllopoda subgroup. They are capable of reproducing both asexually and sexually, but are typically asexual. Daphnia are very prone to sudden die-offs due to environmental changes. Causing the organisms to reproduce sexually would increase their genetic variation as a species, which would in turn allow them to survive adverse conditions more easily. Ammonium chloride is a compound that can frequently be found in adhesives, fertilizers, and plastics. Because ammonium chloride is in fertilizers, it is often found in bodies of water due to runoff, in addition to pollution. High levels of ammonium chloride are known to have detrimental effects on marine life. However, a study by researchers at Oregon State University found that ammonium chloride causes diatoms to transition from asexual to sexual reproduction. In my experiment, I exposed Daphnia magna, a type of small crustacean, to different concentrations of ammonium chloride in order to cause them to transition from asexual to sexual reproduction. Daphnia are capable of both modes of reproduction, but typically only reproduce asexually,

I exposed the daphnia to ammonium chloride by diluting it in their water. I included a control group with no ammonium chloride as well as three experimental groups containing 100 UM, 75 UM, and 50 UM of ammonium chloride. The daphnia were observed for four days in these concentrations. I differentiated between asexual and sexual daphnia through the presence of males and the appearance of the female eggs. The first step of sexual reproduction in daphnia is the production of males. Sexually reproducing daphnia carry eggs with an outer lining. Asexual eggs do not have this lining. Because daphnia are so sensitive to their surroundings, I experienced many instances of sudden die of throughout my project, which prevented me from running multiple trials. The results of this experiment did not show a correlation between ammonium chloride and the sexual reproduction of daphnia magna. However, the pregnancy rate dropped in all four experimental groups, including the control. Although all the tanks experienced pregnancy decrease, the 100 and 50 UM groups experienced a more drastic and sudden change. This suggests that ammonium chloride may have caused the pregnancy rate of the daphnia magna to drop more rapidly than the control group.