As the environmental catastrophe from the Deepwater Horizon oil spill unfolds along the northern Gulf of Mexico, the persistent and unacceptable “Dead Zone” along the Louisiana shore continues to threaten living resources including humans that depend on fish, shrimp and crabs. Excess nutrients, particularly nitrogen and phosphorus, cause huge algae blooms whose decomposition leads to oxygen distress and even organism death in the Gulf's richest waters.

The June forecast of the size of the hypoxic zone in the northern Gulf of Mexico for July 2010 is that it will cover between 19,141 to 21,941 km² (average 20,140 km²; equal to 7,776 mi²) of the bottom of the continental shelf off Louisiana and Texas. The area is about the size of the state of New Jersey.  The estimate is based on the May nitrogen loading (as nitrate+nitrite) from the Mississippi watershed to the Gulf of Mexico estimated by the U.S. Geological Survey. If the area of hypoxia becomes this large, then it will be the fifth largest since systematic mapping of the hypoxic zone began in 1985.

Caveats: 1) This predictions discounts the effect of large storm events which will temporarily disrupt the physical and biological system attributes promoting the formation of the low oxygen zone in bottom waters; 2) The potential space on the shelf where hypoxia occurs is limited by the bathymetry; 3) The predictions assume continued above average discharge through June and July; 4) unusual weather patterns affecting coastal winds, as experienced in 2009, may skew the prediction to be higher, or lower.

Furthermore, the effects of the Deepwater Horizon oil spill are undefined, but potentially significant.

View the entire report in PDF format:
2010 Gulf Hypoxia Forecast

For more information on hypoxia in the Gulf of Mexico, visit http://www.gulfhypoxia.net