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Northern Gulf of Mexico Hypoxic Zone

2014 Forecast: Summer Hypoxic Zone Size, Northern Gulf of Mexico

The National Oceanic and Atmospheric Administration (NOAA) and the Louisiana Universities Marine Consortium (LUMCON) released their forecast for the summer Hypoxic Zone Size in the Northern Gulf of Mexico on June 24, 2014. You can find the full forecast document on the LUMCON Shelfwide Cruise 2014 website and a press release from NOAA here

Scientists are expecting an average, but still large, hypoxic or "dead zone" in the Gulf of Mexico this year. NOAA-supported modeling is forecasting this year's Gulf of Mexico hypoxic zone to cover an area ranging from about 4,633 to 5,708 square miles (12,000 to 14,785 square kilometers) or about the size of the state of Connecticut. The Annual Shelfwide Cruise will take place July 26 - August 3, 2014.

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 2 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.

Information about the size of the hypoxic zone can be obtained from NOAA’s Gulf of Mexico Hypoxia Watch and the Louisiana Universities Marine Consortium (LUMCON), 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.

2013 Hypoxic Zone

The 2013 area of low oxygen in the Gulf of Mexico, commonly known as the hypoxic zone or ‘Dead Zone,’ was 15,120 square kilometers (= 5,800 square miles), which was smaller than predicted. Researchers suggest that winds may have contributed to more mixing and a smaller zone measurement. The size of this year’s hypoxic zone is about double the measured size of the zone in 2012, when summer drought conditions in the Mississippi River Basin contributed to greatly reduced nutrient outputs into the Gulf of Mexico. This year’s zone of oxygen-depleted bottom-water was above both the long-term average and also the five-year average.

Gulf Hypoxic Zone 1985-2013

Size of the Gulf of Mexico hypoxic zone from 1985 to 2013. Source: N. Rabalais
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2013 Hypoxic Zone Measurements

2013 Hypoxic Zone Measurements.
Source: NOAA Gulf of Hypoxia Watch
Click to see larger image


The following links provide information regarding the 2012 hypoxic zone and relation to the Summer 2012 drought:

NOAA scientists: Midwest drought brings fourth smallest Gulf of Mexico 'Dead Zone' since 1985 Exit EPA Disclaimer

Louisiana University Marine Consortium Shelfwide Cruise 2012 Website Exit EPA Disclaimer

Louisiana University Marine Consortium Shelfwide Cruise 2012 Press Release (4pp, 563K, About PDF)

The New York Times Green Blog: Big Drought Makes for a Small 'Dead Zone' Exit EPA Disclaimer

Hypoxic Zone over the Years

The Flash animation below shows a comparison of how the hypoxic zone has changed over the last 5 years (2009 to 2013).

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Graphic created from hypoxic zone measurements available from NOAA Gulf of Hypoxia Watch.

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