Gulf of Mexico ‘dead zone’ getting larger

Would be size of New Jersey

Steve Hawley, Jun 24, 09.

UPDATE (7/29/09, 5:10 pm): “Gulf ‘dead zone’ smaller than expected, more severe”

The Gulf of Mexico “dead zone”—an area of extremely low oxygen levels caused primarily by agricultural runoff—is expected to grow to the size of New Jersey this summer and threaten rich fishing grounds, according to the Houston Business Journal. The predictions were created by scientists at the University of Michigan.

The article notes, “The four largest Gulf dead zones ever measured have occurred since 2001. The biggest of these oxygen-starved, or hypoxic, regions was in 2002 and measured 8,484 square miles.” The dead zone is expected to be one of the largest on record—between 7,450 and 8,456 square miles.

The article quotes Donald Scavia, director of the University of Michigan Graham Environmental Sustainability Institute, who said, “The growth of these dead zones is an ecological time bomb. Without determined local, regional and national efforts to control them, we are putting major fisheries at risk.”

The dead zone is caused by excess nitrogen and phosphorus, mostly from farms in the vast Mississippi River watershed. The nutrient-rich runoff causes massive algae blooms in the Gulf, but when the algae die, the decomposition process consumes most of the oxygen in the area.

In the image above, based on 2004 data from the National Oceanic and Atmospheric Administration, reds and oranges depict the most severe oxygen depletion. According to the researchers, this area is roughly half the size expected in 2009.