2026 'Dead Zone' is Smaller Than Average Following Tropical Storm Bertha

August 4, 2026

Louisiana before weakening over Texas. The 2026 mid-summer size is the third smallest since mapping began in 1985. While the 2026 size falls near the Hypoxia Action Plan goal, it is only one year of many since the Plan was adopted in 2001 and represents physical mixing of the water column.

The water mass with oxygen concentrations less than 2 parts per million forms in bottom waters each year primarily because 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 can stress organisms and may even cause their death, threatening living resources, including fish, shrimp and crabs caught there. Low oxygen conditions started to appear 55 years ago when agricultural practices intensified in the U.S. Midwest. No significant reductions in the nitrate loading from the Mississippi BATON ROUGE – The recent mapping of the "Dead Zone" in the northern Gulf of Mexico in late July – early August 2026 estimated an area of 1332 square miles (3449 square kilometers) of the bottom of the continental shelf off Louisiana and Texas. While the prediction in May 2026 was that the size would be larger than average, the lack of river discharge for the remainder of the month and until the time of the mapping was less than average. Also, Tropical Storm Bertha formed over Panama City, Florida, on July 19 in the northeastern Gulf of Mexico and followed an unusual westward path through July 24 along the northern Gulf coast, making two landfalls in River to the Gulf of Mexico has occurred since the Hypoxia Action Plan was adopted in 2001. The full prediction report is posted at https://gulfhypoxia.net/research/shelfwide-cruises



Additional Link:
Gulf of Mexico Hypoxia: https://gulfhypoxia.net/

Further Information Please Contact:
C. Glaspie, LSU, cglaspie1@lsu.edu
R. E. Turner, LSU, euturne@lsu.edu
N. N. Rabalais, LSU, nrabal@lsu.edu