The overuse of fertilizer can cause algal blooms. How do algal blooms affect a body of water?

Algal blooms can significantly disrupt aquatic ecosystems by depleting oxygen levels in the water, leading to hypoxia or even dead zones where fish and other marine life cannot survive. They can also produce toxins that harm aquatic organisms and pose health risks to humans and animals. Additionally, algal blooms can block sunlight from reaching submerged plants, disrupting photosynthesis and further harming the ecosystem. Overall, these blooms can lead to decreased water quality and biodiversity.