Nutrient runoff significantly impacts aquatic ecosystems by contributing to eutrophication, where excessive nutrients lead to algal blooms that deplete oxygen levels. This process can cause fish kills and loss of biodiversity, disrupting food webs and altering habitat structures. The degradation of water quality affects not only the health of aquatic life but also human activities dependent on these ecosystems. Controlling nutrient runoff is crucial to maintaining ecosystem balance and ensuring sustainable use of water resources.