Causes of hypoxia in Gulf of Mexico
To the editor:Recent articles have suggested that agriculture is responsible for hypoxia in the Gulf of Mexico. Hypoxia is the absence of oxygen reaching living tissues. In the Gulf of Mexico and in other water bodies worldwide, an overabundance of nutrients encourages algal growth, which subsequently reduces sunlight and oxygen and promotes the loss of aquatic habitat. Nutrients such as nitrogen and phosphorus have been conclusively shown to be the main nutrients responsible for the dead zone in the Gulf of Mexico.
May of these recent articles suggest that nitrogen and phosphorus fertilizer runoff from agricultural lands, combined with soil erosion, is the sole source for these nutrients. However, credible evidence shows that nutrients may also be derived from atmospheric deposition, sewage and industrial discharge and fertilizer runoff from residential areas. Nutrient runoff from suburban areas roughly equals that of agricultural lands.
Agricultural runoff does contribute a portion of the nitrogen and phosphorus load destined for the Gulf of Mexico. However, industry lead solutions include controlled drainage/irrigation systems, precision nutrient application technologies, innovative soil-pasture management systems and the best nutrient management system, all of which appreciably limit nutrient runoff. Thus, agricultural industries and farmers/ranchers in the 31 states that are drained by the Mississippi River recognize the severity of the problem, are providing solutions and are promoting soil and water stewardship for future generations.
MICHAEL AIDE, Department of Agriculture, Southeast Missouri State University, Cape Girardeau