Summer 'Dead Zone' Expert Notes Connection to Midwest Corn Planted for Ethanol

Published: July 11, 2014

Summer 'Dead Zone' Expert Notes Connection to Midwest Corn Planted for Ethanol

CORPUS CHRISTI, Texas – Another summer of high temperatures is expected to create a dead zone in the Gulf of Mexico that is about as big as Connecticut.

The National Oceanic and Atmospheric Administration (NOAA) predicts a “dead zone” ranging from 4,633 to 5,708 square miles in the Gulf this summer, stretching from South Texas all the way to Alabama. 

Dr. Larry McKinney, executive director of the Harte Research Institute for Gulf of Mexico Studies (HRI), has studied these dead zones, also known as hypoxia zones, for more than 20 years.

The dead zone is caused when nitrogen-based fertilizer washes off farm fields in the Midwest corn-belt and ends up in the Mississippi River, which flows into the Gulf.  Just as nitrogen-based fertilizer makes corn grow, it also stimulates the growth of plants in the water, mainly algae. The algae bloom eventually die and decay. This process removes oxygen from the water, resulting in oxygen-depleted water where some marine life can’t live.

Prized Gulf seafood like shrimp, crabs and clams are particularly threatened by the dead zone 

“The Gulf produces roughly 40 percent of all the seafood in the lower 48 states, so as the dead zone grows year-after-year -- as it has for the past decade -- more and more fishermen face economic difficulty,” McKinney said. “This dead zone costs the seafood and tourism industry $82 million a year, dealing a blow to the Gulf Coast economy.”

This year’s dead zone is expected to be smaller than last year’s, but still of concern along the Gulf coast, an area that accounts for about 18 percent of the total commercial seafood sold in the United States

McKinney and other dead zone experts are concerned the size and duration of this dead zone may begin hundreds of miles away in the Corn Belt. If it is connected to fertilizers coming down the Mississippi, as studies indicate, the aggressive expansion of a U.S. biofuel policy is driving the rapid escalation of corn planted for fuel production and that could mean more fertilizer and fertilizers fuels dead zone conditions.

McKinney said he is concerned about the unintended consequences of a well-meaning policy, stating that the proposed reductions in the biofuel blending requirements from the Environmental Protection Agency could prevent increasing fertilizer runoff -- but only for this year.

“Until we fully understand these linkages we should not be promoting policies that may cause more harm than good,” he said.

Dead zones normally peak in July and August, and start to break-up in the fall.  Tropical storms or a hurricane could stir up the water and re-oxygenate the area.