Nutrient Control Action for Improving Water Quality

A large area of coastal waters in the northern Gulf of Mexico experiences seasonal conditions of low levels of dissolved oxygen, a condition known as hypoxia. This zone of hypoxia has been persistent since consistent data collection on its distribution and dynamics was begun in 1985. Excess discharge of nutrients—especially nitrogen and phosphorus—into the Gulf of
Mexico from the Mississippi and Atchafalaya rivers causes nutrient overenrichment in the gulf’s coastal waters and stimulates the growth of large algae blooms. When these algae die, the process of decomposition depletes dissolved oxygen from the water column and creates hypoxic conditions.