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Mississippi River/Gulf of Mexico Hypoxia Task Force

Northern Gulf of Mexico Hypoxic Zone

2017 Gulf of Mexico Hypoxic Zone Size2017 Hypoxic Zone SizeDistribution of bottom-water dissolved oxygen, July 24 – July 30, 2017. Black line denotes 2 mg/L .

Data source: N. N. Rabalais, Louisiana State University & Louisiana Universities Marine Consortium; R. E. Turner, Louisiana State University.

Funding source: National Oceanic and Atmospheric Administration, National Centers for Coastal Ocean Science. 

The 2017 “Dead Zone” measured 22,720 square kilometers (8,776 square miles). This size is close to the forecast made in June as described below. The 2017 dead zone size is above the five-year average (15,032 sq km). It is also more than four times larger than the Hypoxia Task Force Goal of 5,000 square kilometers. Researchers suggest that the Mississippi River May discharge, which was well above average, provides an explanation for most of the large zone measurement. For more information, read the Louisiana Universities Marine Consortium (LUMCON)Exitand the National Oceanic and Atmospheric Administration (NOAA) press releases.

2017 Forecast: Summer Hypoxic Zone Size, Northern Gulf of Mexico

NOAA and the United States Geological Survey (USGS) released their 2017 forecast for the summer hypoxic zone size in the Northern Gulf of Mexico on June 20, 2017. Read the full press releaseExit. Scientists are expecting the 2017 area of low oxygen, commonly known as the 'Dead Zone,' to be approximately 8,185 square miles, or about the size of New Jersey. This prediction is large primarily because of high stream flow levels measured in May.

2016 Cruise to Measure Gulf of Mexico Hypoxic Zone Size Cancelled

Due to mechanical problems with the NOAA ship designated for the measurement cruise, the hypoxic zone was not measured in 2016. Read the full press release for more informationExit

2015 Gulf of Mexico Hypoxic Zone Size

2015 Gulf of Mexico Hypoxic ZoneDistribution of bottom-water dissolved oxygen July 28-August 3, 2015 (west of the Mississippi River delta). Black line indicates dissolved oxygen level of 2 mg/L. 

Data: Nancy R. Rabalais, LUMCON, and R. Eugene Turner, LSU. Credit: NOAA.

Funding sources: NOAA Center for Sponsored Coastal Ocean Research and U.S. EPA Gulf of Mexico Program 

The 2015 “Dead Zone” measured 16,760 square kilometers (6,474 square miles). This size is larger than the predicted range 

made in June as described below. The 2015 dead zone size is above the five-year average (14,024 sq km). It is also three times larger than the Hypoxia Task Force Goal of 5,000 square kilometers.  Researchers suggest that heavy rains in June and high river discharges in July may provide an explanation for the larger zone measurement. Read the Louisiana Universities Marine Consortium (LUMCON)Exit and the National Oceanic and Atmospheric Administration (NOAA) press releases.

2015 Forecast: Summer Hypoxic Zone Size, Northern Gulf of Mexico

NOAA and the United States Geological Survey (USGS) released their 2015 forecast for the summer hypoxic zone size in the Northern Gulf of Mexico on June 17, 2015. Read the full press release. Scientists are expecting the 2015 area of low oxygen, commonly known as the 'Dead Zone,' to be approximately 5,483 square miles or about the size of Connecticut –the same as it has averaged over the last several years.

2014 Gulf of Mexico Hypoxic Zone Size
2014 Gulf of Mexico Hypoxic ZoneDistribution of bottom-water dissolved oxygen July 27-August 1, 2014 (west of the Mississippi River delta). Black line indicates dissolved oxygen level of 2 mg/L. 

Data source: Nancy R. Rabalais, LUMCON, and R. Eugene Turner, LSU

Funding sources: NOAA Center for Sponsored Coastal Ocean Research and U.S. EPA Gulf of Mexico Program 

The 2014 "Dead Zone" measured 13,080 square kilometers (5,052 square miles) as of Aug 1, 2014. This size fell within the predicted range made in June described below. The 2014 dead zone size is below the five-year average (14,353 sq km), but still well above the Hypoxia Task Force goal of 5,000 square kilometers. Read the LUMCON press release Exit and the NOAA press release.

Measuring the Hypoxic Zone

The hypoxic zone in the northern Gulf of Mexico is an area along the Louisiana-Texas coast, where water near the bottom of the Gulf contains less than two parts per million of dissolved oxygen, causing a condition referred to as hypoxia.

Each summer, the size of the hypoxic zone is measured. The size of the zone is an important indicator of how much progress is being made to reduce nutrient inputs into the Gulf of Mexico. Sometimes the size of the zone is influenced by other factors, such as droughts or hurricanes that can reduce the size of the zone, or floods that can increase the size.

2014 Gulf of Mexico Hypoxic Zone Size Bar GraphData source: Nancy N. Rabalais, LUMCON, and R. Eugene Turner, LSU

Information about the size of the hypoxic zone can be obtained from NOAA’s Gulf of Mexico Hypoxia Watch and the LUMCONExit, which is supported by NOAA’s NGOMEX.

The Gulf of Mexico Hypoxia Watch evolved as a cooperative project among NOAA’s National Marine Fisheries Service (NMFS), the National Coastal Data Development Center (NCDDC), and the CoastWatch - Caribbean/Gulf of Mexico - Regional Node. The objective of Hypoxia Watch is to develop new near-real time data and map products using shipboard measurements of bottom-dissolved oxygen and disseminate them over the Internet. Access measurements taken from 2001 to the current season