The addition of phosphorus to water bodies can have a number of negative effects on aquatic ecosystems. Phosphorus is a nutrient that can spur the growth of aquatic plants and algae. When there is an overabundance of phosphorus in a water body, it can lead to an increase in the growth of these plants and algae. This can lead to a decrease in the amount of oxygen in the water, as well as an increase in the amount of harmful toxins. This can create an imbalance in the aquatic ecosystem and can lead to the death of fish and other organisms.