This study's research focused on the effect of urea on coral bleaching. The process of coral bleaching occurs when symbiotic dinoflagellates, called Zooxanthellae, within coral host cells produce a surplus of Reactive Oxygen Species (ROS), such as hydrogen peroxide, which degrade their host cell's internal organelles. This subsequently leads to the exocytosis of the dinoflagellate symbiotes, resulting in the death of the symbiote and a loss in the nutrients they provide their host cells. This study examines the effect of urea on this process. Urea was used as a treatment due to the high concentrations found in oceanic runoff and the current proposal to dump urea into oceans to bloom the dinoflagellate species Lingulodinium polyedrum as a carbon sink. However, the effect of the human induced increasing urea concentrations in the ocean could pose threat to more sensitive dinoflagellates such as Zooxanthellae. This study examined the effect of urea on the ROS generation and reproductive viability of the symbiotic dinoflagellate Gymnodinium. I predicted that Dinoflagellate cultures exposed to temperature increases and the presence of urea will depict an increase of hydrogen peroxide production and decrease in growth rate, while both of these treatments present simultaneously will magnify the expected results above. For treatments, rising ocean temperatures were mimicked through an increase in water temperatures to 31 degrees celsius. Subtle concentrations of urea were added to cultures of Gymnodinium both experiencing temperature increases and subjected to normal growth temperatures. The change in hydrogen peroxide concentrations in cultures was recorded after a day of treatment using a UV spectrophotometer to measure this increase of 240 nm light absorbed which correlates with catalase activity and therefore hydrogen peroxide abundance. The change in the number of cells in each culture was also measured with a hemocytometer after a day of treatment. Results demonstrate that the presence of urea in cultures, when compared to the normal increasing trend when heat was applied, significantly increased the dinoflagellates production of hydrogen peroxide, Additionally, the presence of both urea and heat in cultures showed a significant decrease in the survivability of cells compared to the subtle decrease of just urea of heat present. It can be concluded then that urea increases the oxidative stress experienced by symbiotic dinoflagellates. This conclusion implies that before proceeding with solutions to global warming such as urea dumping, it is necessary to look at the indirect effect they have on other species of organisms such as the risk urea poses to sensitive and vital dinoflagellates such as Gymnodinium.