2022 ‘Dead Zone’ May Remain Three Times Larger than the Goal Established in 2001
June 02, 2022
BATON ROUGE – A recent forecast of the size of the “Dead Zone” in the northern Gulf of Mexico for late July 2022 is that it will cover 5,881 square-miles of the bottom of the continental shelf off Louisiana and Texas. The Mississippi River discharge of nitrogen in May controls the size of this zone, which will be the 20th largest zone since systematic measurements began in 1985. The water mass with oxygen concentrations less than 2 parts per million forms in bottom waters each year primarily as a result of nitrogen loading from the Mississippi River watershed, which fertilizes the Gulf of Mexico’s surface waters to create excessive amounts of algal biomass. The decomposition of this plant material in the bottom layer and sediments leads to oxygen loss.
The low oxygen conditions in the Gulf of Mexico’s most productive waters stresses organisms and may even cause their death, threatening living resources, including fish, shrimp and crabs caught there. Low oxygen conditions started to appear 50 years ago when agricultural practices intensified in the Midwest. No reductions in the nitrate loading from the Mississippi River to the Gulf of Mexico has occurred since the Hypoxia Action Plan was adopted in 2001. The predicted hypoxic area is about three times the land area of Rhode Island and about three times the size of the Hypoxia Action Plan goal established in 2001. This estimate assumes that there are no significant tropical storms in the two weeks before or during the annual monitoring cruise planned for July 25 to August 1. The estimate is made each year by LSU scientists R. Eugene Turner and Nancy N. Rabalais. The full report is posted at https://gulfhypoxia.net/research/shelfwide-cruises/.