The mass fish kills will continue.
The effects of this spring’s extreme flooding of the Mississippi River have been – pardon the pun – spilling over into every possible corner of the area’s residential, commercial, and agricultural life over the last two months. And it looks like the environment hasn’t escaped either: researchers from the University of Michigan predict that the largest Gulf of Mexico “dead zone” on record will result from the flooding.
The dead zone is forecast to be between 8,500 and 9,421 square miles – an area roughly the size of New Hampshire, according to the U.S. National Oceanic and Atmospheric Administration (NOAA). The zone is a threat to aquatic organisms as well as the humans who depend on them in the gulf’s booming seafood industry.
“Stream flows were nearly double normal during May, delivering massive amounts of nutrients to the Gulf, and that’s what drives the dead zone,” said Donald Scavia, Special Counsel to the U-M President for Sustainability and director of the Graham Sustainability Institute.
(See pictures of flood waters rising along the Mississippi river.)
Scavia noted that the most likely 2011 scenario is a Gulf dead zone of at least 8,500 square miles. This estimate far surpasses the 6,000-square-mile average of the past five years, as well as the current record, set in 2002, of 8400 miles.
The oxygen-starved Gulf dead zone is largely caused by farmland runoff containing fertilizers and livestock waste from as far away as the Corn Belt. Nitrogen and phosphorus from these sources flow down the Mississippi River and into the Gulf in late spring and summer each year, prompting explosive algal blooms, which later die and sink to the ocean floor. As they decompose, the algae provide bottom-dwelling bacteria with organic matter to feast on. Oxygen is consumed in the process, producing an oxygen-starved region in bottom and near-bottom waters: a dead zone.
This year, nitrogen and phosphorus have been seeping from Mississippi and Atchafalaya Rivers into the Gulf in alarmingly high amounts. In May 2011, 164,000 metric tons of nitrogen were transported to the northern Gulf, according to the U.S. Geological Survey – a 35% climb from average May nitrogen estimates in the last 32 years. The Gulf has seen a shocking 300% increase in nitrogen content since 1960.