Since 1985, the size of the hypoxic zone in the Gulf of Mexico has been measured every July via a cruise on the Pelican, a ship operated by the Louisiana University Marine Consortium under the direction of Dr. Nancy Rabalais. The hypoxic zone, colloquially referred to as the “dead zone,” is an area where nutrient-enriched waters coming from freshwater rivers and streams in the watershed cause excess growth of plants which, in turn, deplete oxygen levels as they decompose. The extent of oxygen depletion is nearly complete in that it creates unsuitable habitat for animals living in the region. The result of this year’s annual cruise indicated an area of low oxygen level of about 5,800 square miles, an area roughly three times as large as the targeted goal. A significant source of the nutrients that flow into the Gulf originate from agricultural sources, specifically row crop land in the corn belt.
Kling, Catherine L.
"The Iowa Nutrient Reduction Strategy to Address Gulf of Mexico Hypoxia,"
Agricultural Policy Review: Vol. 2013
, Article 1.
Available at: https://lib.dr.iastate.edu/agpolicyreview/vol2013/iss1/1