Eutrophication

Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of microorganisms that may deplete the water of oxygen. When occurring naturally, eutrophication is usually caused by the natural accumulation of nutrients from dissolved phosphate minerals and dead plant matter in water. Manmade or "cultural eutrophication" is often a more rapid process in which a variety of polluting inputs including poorly treated sewage, industrial wastewater, and fertilizer runoff flows into the water. Such nutrient pollution usually results algal blooms and bacterial growth, resulting in the depletion of dissolved oxygen in water and causing substatial environmental degradation.

Approaches for prevention and reversal of eutrophication include minimizing point source pollution from sewage and agriculture as well as other nonpoint pollution sources. Additionally, the introducution of bacteria and algae-inhibiting organisms such as shellfish and seaweed and in can also help reduce nitrogen pollution, which in turn controls the growth of cyanobacteria, the main source of harmful algae blooms.