Dead Zone in Gulf of Mexico is Big, Though Not as Big as Feared

This year's dead zone located off the coast of the Southeastern United States in the Gulf of Mexico, though big, is not a large as feared, NOAA announced Monday.

Dead -- or hypoxic -- zones result when runoff derived from agricultural and other human activities reach the watershed, causing an overgrowth of algae that sinks, decomposes and consumes much of the oxygen needed to support life.

With this in mind, many researchers braced for the worst based on flood conditions in the Midwest that tranpsorted a large number of nutrients from the Mississippi watershed downstream.

"A near-record area was expected because of wet spring conditions in the Mississippi watershed and the resultant high river flows which deliver large amounts of nutrients," Nancy Rabalais, executive director of the Louisiana Universities Marine Consortium (LUMCON), said in a press release.

And had it been up to humans alone, that very well could have been the case. However, as Rabalais, who led the dead zone survey cruise noted, "nature's wind-mixing events and winds forcing the mass of low oxygen water towards the east resulted in a slightly above average bottom footprint."

All told, this year's hypoxic zone measured 5,840 square miles, or roughly the size of Connecticut.

This comes a year after the fourth smallest dead zones on record, which, due to intense drought conditions upstream, measured just 2,889 square miles, or slightly larger than Delaware.

In contrast, the smallest dead zone ever recorded took place in 1988 and covered just 15 square miles, while the average over the past five years has been 5,176 square miles -- a number that represents more than twice the 1,900 square mile goal set by the Gulf of Mexico/Mississippi River Watershed Nutrient Task Force in 2001 and later reaffirmed in 2008.

Each year, the hypoxic zone off the coast of Louisiana and Texas threatens the local ecosystem, essentially starving all fish and animal life out. As a result, commercial and recreational Gulf fisheries worth hundreds of millions of dollars struggle to make ends meet. Furthermore, in its 2008 report the task force warned that not only does hypoxia carry with it a host of short term problems, but that long term ecological changes in species diversity and the ecosystem's food-web that is both "difficult and impossible to reverse."

In order to gain a better idea of this year's dead zone, researchers are scheduled to conduct a follow-up cruise in mid-August to provide a final season update.