What is the impact of eutrophication on aquatic ecosystems?

The impact of eutrophication on aquatic ecosystems is primarily characterized by the reduction of oxygen levels in water, which can lead to the formation of dead zones. Eutrophication occurs when excess nutrients, usually nitrogen and phosphorus, enter aquatic environments, often due to runoff from agriculture or urban areas. This nutrient overload results in algal blooms, which can proliferate rapidly.

When the algae die, their decomposition consumes a significant amount of dissolved oxygen in the water, leading to hypoxic conditions (low oxygen levels). Aquatic organisms, particularly fish and invertebrates, require adequate oxygen to survive, and when oxygen levels dwindle, it can result in massive die-offs of these species, turning affected areas into 'dead zones' where life is unsustainable. This phenomenon disrupts the balance of the ecosystem, reduces biodiversity, and can have cascading effects on food webs and ecosystem health.

In contrast to the correct answer, options that suggest promoting biodiversity, stabilizing sediment, or decreasing nutrient loads do not accurately reflect the primary impacts of eutrophication. Instead, they underscore complexities that can occur in a balanced or well-managed aquatic environment.