• The Mississippi: A Visual Biography by Quinta Scott

    "Great book and great blog - thanks for the first book I have seen that addresses the contemporary river, headwaters to gulf." Dan McGuiness, Audubon, St. Paul, Minnesota

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The Flood of 2008–The Dead Zone

In the Spring of 2008 it rained and rained just as Midwest farmers had fertilized their fields with nitrogen-based fertilizers. The rain washed the fertilizers into streams that flow to the Mississippi, which carried them to the Gulf of Mexico. 

When the nitrate-laden freshwater from the Mississippi, lighter than the Gulf’s saltwater, reaches the Gulf, it floats on the surface. Most of the year wind mixes the fresh into the salt, but in summer the Gulf is calm and the fresh lays on top of the salt.

The nitrate-rich freshwater fertilizers algae, which bloom, die, and sink into the saltier layer, where they decompose and soak up the available oxygen, creating a hypoxic zone, a Dead Zone.  

Fish and shrimp flee the Dead Zone. Plants, plankton, and oysters, which cannot flee die. Fish and shrimp, which move to Louisiana’s coastal wetlands to breed, cannot cross the the Dead Zone when they migrate from their nurseries to the Gulf.

Hypoxia is a natural phenomenon, but the levels of dissolved nitrogen jumped dramatically after the 1950s as Midwest farmers applied more and more fertilizers to their fields. After the Flood of 1993 it increased to the size of New Jersey. After the Flood of 2008 Louisiana scientists predicted that it would balloon to 10,000 square miles.

In a normal year should farmers spread more fertilizer on their fields than their corn, wheat, or soybeans can absorb, the excess flows to the watershed, creating a Dead Zone in the Mississippi.

The Gulf is the most important commercial and recreational fisheries in the United States. The Dead Zone is a threat to Louisiana’s economy.

In December 11, 2008 the National Research Council called for the EPA to set limits on the use of fertilizer in the Mississippi Basin. 

This was the second time the National Research Council addressed the EPA on water quality in the Mississippi Basin. Previously, it found that the EPA had failed to oversee water quality in the basin, during it into an orphan.

When I first began to study the Mississippi fifteen years ago, I haunted the annual meeting of the late Mississippi River Basin Alliance, where I first learned about the Dead Zone and the reluctance of Midwest farmers to reduce their use of fertilizers that create the Dead Zone.

When I first moved to Monroe County, Illinois, where agriculture is the major industry, I was involved in a project that tried to talk to farmers about leaving vegetative buffers along the streams drainage ditches that run through their fields. I was stood up, hung up on, and stonewalled. 

 

Take Fountain Creek in Monroe County, Illinois. Fountain Creek rises in the uplands and loops across farm fields, devoted to corn, wheat, and soybeans, gathering runoff, including excess nutrients. It flows out of the uplands and across the American Bottom, that vast floodplain that stretches from the mouth of the Missouri 100 miles south to the mouth of the Kaskaskia River.

 

Fountain Creek, Monroe County, Illinois, Flood of 1993

Fountain Creek, Monroe County, Illinois, Flood of 1993

 

 

On the bottoms, it is truncated into two streams. The Columbia (Illinois) Levee District has harnessed its main channel between levees which carry it and its nutrients to the Mississippi, but which keeps the creek from flooding valuable agricultural land. The rest of Fountain Creek, the truncated channel, continues across the bottoms to the Main Line Levee that protects the bottoms from Mississippi River flooding. At the levee a pump pumps water and nutrients from the creek through the levee and to the Mississippi.

 

Old Channel Fountain Creek, Monroe County, Illinois

Old Channel Fountain Creek, Monroe County, Illinois

 

 

For the most part, farmers on the bottoms till their fields right up to the edge of the truncated channel. Excess fertilizers wash off the fields into the old channel of Fountain Creek and are pumped to the Mississippi. Even through a narrow buffer of young trees line the tail end of Fountain Creek, it is not enough to soak up the excess nutrients that flow to it.

To learn more about the Dead Zone, go to the National Oceanic and Atmospheric Adminstration’swebsite and read the following article.

Text and Images, Copyright, 2008, Quinta Scott, All Rights Reserved

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