Agricultural runoff significantly impacts marine ecosystems by introducing excess nutrients, pesticides, and sediments. When fertilizers wash into water bodies, they can lead to eutrophication, resulting in algal blooms that deplete oxygen levels and harm aquatic life. These blooms can cause dead zones where marine organisms struggle to survive. Additionally, pesticides may accumulate in the food chain, affecting biodiversity and the health of marine species. Addressing runoff is vital for preserving marine health and ecosystem integrity.