Each spring and summer in the Gulf of Mexico, nutrient-rich ef- fl uent from the Mississippi and Atchafalaya Rivers stimulates algae growth. The rates of growth are typically so high that when the algae die and decompose, they consume more dissolved oxygen than can be replenished by the ocean. The Gulf hypoxic zone or “dead zone” is created when dissolved oxygen levels become too low to support sea life.
Babcock, Bruce A. and Kling, Catherine L.
"Costs and Benefits of Fixing Gulf Hypoxia,"
Iowa Ag Review: Vol. 14
, Article 4.
Available at: http://lib.dr.iastate.edu/iowaagreview/vol14/iss4/4