The Dead Zone and Mississippi River

The Dead Zone and Mississippi River

Since Gulf Restoration Network’s founding in 1994, one of our priority issues has been advocating for the reduction of the nitrogen and phosphorous pollution in the Mississippi that causes the Dead Zone, an area of low oxygen that forms every summer in the Gulf where aquatic life must swim away or suffocate and die. GRN’s work on Mississippi River pollution includes:

  • Pushing states and/or the EPA to establish limits on nitrogen and phosphorus pollution in the Mississippi River and its tributaries.
  • Monitoring and pushing for enforcement of permits to polluters who are putting nitrogen and phosphorus into the water. 
  • Advocating for changes in the way farm subsidies are distributed so that farmers who are demonstrating conservation practices that reduce nitrogen runoff receive proper funding and taxpayers are not subsidizing pollution.

The Mississippi River is truly one of the great natural resources of our country. In addition to providing drinking water for more than eighteen million people, the Mississippi and its tributaries provide an engine for economic development, an important transportation link, abundant recreational opportunities and a vast habitat for wildlife.  Forty percent of the nation’s migratory waterfowl fly along the Mississippi River corridor, and the Mississippi supports a whopping 260 fish species.

The Mississippi River, however, is not without problems. As the Mississippi meanders southward, it picks up contaminants, including sediment, mercury and pesticides. In addition, nitrogen and phosphorus pollution from upstream farms using excess fertilizer, urban storm sewers and sewage treatment plants combine to create a Dead Zone in the Gulf. The nitrogen and phosphorus polluted water acts as a fertilizer of algae, resulting in large algal blooms. When the algae die, they sink to the saltier water below and decompose, depleting already low oxygen in the deeper water. Because the salty bottom waters do not mix well with the lighter, fresh water from the Mississippi River, oxygen in the water is not replenished, resulting in a large Dead Zone in bottom waters.

dead zone formation USEPA
Credit: U.S. EPA

Though the size of the Dead Zone varies each year, it averages approximately 5,000 square miles, or the size of Connecticut. The Dead Zone causes untold costs each year to the $2.8 billion Gulf commercial and recreational fishing industries.

Efforts to improve the health of the Mississippi River and reduce nitrogen and phosphorus pollution that causes the Dead Zone have been plagued by inconsistent implementation of the Clean Water Act, which is carried out by state agencies. The Mississippi River flows through a 10-state corridor, with most of the river lying between state boundaries. While some states have begun to take efforts to reduce nitrogen and phosphorus pollution, others lag far behind.

In order to address the numerous pollution sources throughout the entire Mississippi River, GRN is working with a collaborative of over 20 organizations. Funded by the McKnight Foundation, the Mississippi River Collaborative brings together experts in science, law, policy and advocacy to find ways to reduce pollutants entering the Mississippi. Much of our work is focused on ensuring that the Clean Water Act is implemented and enforced consistently along the Mississippi and that nitrogen and phosphorus pollution levels are reduced.

Additional Resources

Hypoxia Action Plan