What phenomenon is caused by excess phosphorus in water bodies?

Eutrophication is a phenomenon that occurs when a water body receives an excessive input of nutrients, particularly phosphorus, leading to an overgrowth of algae and aquatic plants. This nutrient enrichment typically comes from agricultural runoff, wastewater discharge, or other sources that introduce high levels of phosphorus into lakes, rivers, and coastal areas.

As the algae proliferate, they can block sunlight from reaching underwater vegetation, disrupting the ecosystem. When the algae die off, their decomposition depletes the oxygen levels in the water, which can result in dead zones where aquatic life cannot survive. This process not only affects the health of aquatic ecosystems but can also lead to harmful algal blooms that produce toxins, impacting both wildlife and human health.

Oligotrophication, on the other hand, refers to the process of a water body becoming less nutrient-rich, which typically supports a lower biomass of algae and cleaner water. Desalination involves removing salts from seawater to create freshwater and does not pertain to nutrient enrichment or its effects on aquatic ecosystems. Aeration is a process of increasing oxygen concentration in water but is not a direct result of excess phosphorus.