The Gulf of Mexico’s hypoxic zone is predicted to be larger than average this year, due to extreme flooding of the Mississippi River this spring, according to an annual forecast by a team of NOAA-supported scientists from the Louisiana Universities Marine Consortium, Louisiana State University and the University of Michigan.
‘Hypoxic zones’ render fishing areas low in oxygen, which leads to suffocation, practically no sex drive, low egg-laying, and zero survival for those that do live through the flooding.
The scientists are predicting the area could measure between 8,500 and 9,421 square miles, or an area roughly the size of New Hampshire. The largest ‘dead’ zone measured to date occurred in 2002 and encompassed more than 8,400 square miles.
The average over the past five years is approximately 6,000 square miles of impacted waters, much larger than the 1,900 square miles which is the target goal set by the Gulf of Mexico/Mississippi River Watershed Nutrient Task Force. This collaboration between NOAA, USGS and university scientists facilitates understanding.
Hypoxia is caused by excessive nutrient pollution, often from human activities such as agriculture that results in too little oxygen to support most marine life in bottom and near-bottom water. The hypoxic zone off the coast of Louisiana and Texas forms each summer and threatens valuable commercial and recreational Gulf fisheries.
During May 2011 stream-flow rates in the Mississippi and Atchafalaya Rivers were nearly twice that of normal conditions. This significantly increased the amount of nitrogen transported by the rivers into the Gulf. According to USGS estimates, 164,000 metric tons of nitrogen (in the form of nitrite plus nitrate) were transported by the Mississippi and Atchafalaya Rivers to the northern Gulf. The amount of nitrogen transported to the Gulf in May 2011 was 35 percent higher than average May nitrogen loads estimated in the last 32 years.
Coastal and water resource managers nationwide require new and better integrated information and services to adapt to the uncertainty of future climate and land-use changes, an aging water delivery infrastructure, and an increasing demand on limited resources. NOAA and USGS, as well as the U.S. Army Corps of Engineers, have signed an agreement that will further facilitate collaboration in the future.
The actual size of the 2011 hypoxic zone will be released following a NOAA-supported monitoring survey led by the Louisiana Universities Marine Consortium between July 25 and August 6. Collecting these data is an annual requirement of the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force Action Plan.
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