2018 Dead Zone Smaller, But Still Above Average

Wisconsin algae, photo courtesy of Midwest Environmental Advocates

The National Oceanographic and Atmospheric Administration (NOAA) announced that the size of the 2018 Gulf of Mexico Dead Zone (where the Mississippi River meets the Gulf) is estimated to be smaller than last year, at 5,780 sq. mi, or roughly the size of Connecticut.

While this is good news, to be sure, the Dead Zone is still much larger than would occur naturally because of increasing nitrogen and phosphorus pollution from the entire River basin, which consists of 31 states.

EPA’s Hypoxia Task Force – charged with reducing this pollution up and down the River – has consistently fallen short of expectations. Over the 20 years since its formation, very little progress has been made, and it keeps giving itself permission to postpone its own deadlines. If conditions remain the same, the Gulf of Mexico Dead Zone will continue to expand.

The Gulf Dead Zone forms as a result of a process called eutrophication. When nitrogen and phosphorus pollution enters the Gulf, it causes plant life like algae to flourish, and the plants use so much oxygen that no marine life can survive in the area.

Although the Gulf Dead Zone receives a large share of the attention paid to issues of nitrogen and phosphorus pollution, waterbodies throughout the Basin are affected.

Each summer, many lakes are forced to close due to unsafe conditions. Nitrogen and phosphorus pollution is dangerous to pets (dogs swimming in polluted water have been known to die) and can cause severe reactions in humans. It also seriously jeopardizes the safety of drinking water.

In recent years, the City of Toledo had to cut off its drinking water supply to citizens because of a toxin (microcystin) found in the water. The toxin was released by a large harmful algal bloom (HAB) in Lake Erie caused by agricultural runoff. In addition, the Des Moines Water Works was forced to begin construction on a new $15 million nitrate removal system. (Excess nitrates in drinking water can cause Blue Baby Syndrome.)

The Mississippi River Collaborative works to reduce this pollution by leaning on EPA and state environmental agencies to enact policies that reduce the nitrogen and phosphorus pollution (mostly from sewage treatment plants and large agricultural operations) that flows to the Gulf of Mexico via the Mississippi River. It also seeks to establish national numeric limits for nitrogen and phosphorus levels in waterbodies, without which many pollution reduction efforts are futile.

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