Reducing Nutrient Loads, Especially Nitrate-Nitrogen, to Surface Water, Ground Water, and the Gulf of Mexico

The goal of this report is to identify and evaluate approaches for solving the problem of the hypoxia in the Gulf of Mexico. This zone of low dissolved oxygen, which covers an area from 13,000 to 20,000 km^2 off the shore of Louisiana, has been shown to be due to excess nutrients, particularly nitrate-nitrogen, being transported to the Gulf from the Mississippi River Basin. To accomplish our goal, we (1) reviewed appropriate literature on methods for controlling nutrients, particularly nitrate-nitrogen, from entering waterways; (2) evaluated these methods to reduce the amount of nitrogen released to streams and rivers; (3) put the methods in the context of the entire Mississippi River Basin and the significance of the sources; and (4) presented recommendations for the most reasonable combination of approaches that would be necessary to solve the problem.