Eutrophication is a process where a body of water becomes overly enriched with nutrients, leading to excessive growth of algae and other aquatic plants. This excessive growth can deplete oxygen levels in the water, causing harm to fish and other organisms. Eutrophication can also result in algal blooms, which can release toxins and further deplete oxygen when they decompose, leading to dead zones where aquatic life cannot survive. Overall, eutrophication disrupts the balance of aquatic ecosystems and can have detrimental effects on the biodiversity and overall health of the ecosystem.