2020 Gulf Dead Zone: Small Measurement Doesn’t Mean Small Pollution

The results are in: 2020 Gulf Dead Zone small thanks to Hurricane Hanna, not pollution reductions

The National Oceanic and Atmospheric Administration (NOAA) completed its annual cruise to measure the Gulf Dead Zone earlier this month. Thanks to Hurricane Hanna, the measured size of the Dead Zone this year is significantly smaller than average. This year’s Dead Zone was over approximately 2,100 square miles or 1.4 million acres – larger than the state of Delaware.

Nutrient pollution is an important issue that negatively impacts public health and local economies in states all along the Mississippi River year-round, but the Dead Zone is a phenomenon that is most noticeable during the summer months. At this time of year, warm temperatures plus increased nutrients in water equal a recipe for disaster. Why should we care about the Dead Zone and what does this year’s measurement mean?

Mississippi River Carrying Sediment Creating Algal Bloom in the Gulf of Mexico. Image shot 2007. Source: NASA/Landsat/Phil Degginger / Alamy Stock Photo

What is the Dead Zone anyway?

Nutrient pollution is a serious issue in an agricultural state like Missouri, where I live. As a River Citizen, you might also live in a state that has strong ties to agriculture and farming. As an avid gardener, I know that nutrients like nitrogen and phosphorus are necessary for all plant life. That is, after all, why we call them “nutrients.” But what we have going on in the Mississippi River basin is way too much of a good thing.

When compounded over the entire Mississippi River watershed, excess nutrients create big problems. The Dead Zone describes the area of the Gulf at the mouth of the Mississippi River where water can no longer support marine life because it is starved of oxygen. Excess nutrients over-fertilize the water and spur the growth of massive algal blooms. These algal blooms quickly deplete the water dissolved oxygen. No oxygen means no life and thus, the Dead Zone.

Nutrient pollution isn’t just toxic to fish and aquatic creatures. Harmful algal blooms can produce toxins that cause serious harm to people and pets. We can encounter these toxins through drinking water, fishing, or swimming in our favorite lakes or ponds. Nitrates (another form of nutrient pollution) can also contaminate drinking water sources such as private wells and have fatal consequences on sensitive populations (like infants and blue baby syndrome).

The annual Dead Zone puts a significant economic strain on local fisheries as well as recreation and tourism-based River economies. In fact, NOAA estimates that the “Dead Zone” costs U.S. seafood and tourism industries at least $82 million a year.

Increased precipitation from climate change, increased impervious surfaces (that cause water to run-off rather than be absorbed), and the proliferation of industrialized agriculture in the Mississippi River basin have all contributed to rapid increases in the amount of nutrient pollution in our waterways.

This pollution doesn’t just impact the Gulf of Mexico. Nutrient pollution can impact local rivers, streams, and lakes in all our states. It can close lakes for swimming, poison our pets who might inadvertently take a dip in harmful algal blooms, and kill fish and other wildlife. Overall, nutrient pollution is significantly impacting our outdoor recreation and tourism economy.

The annual Dead Zone puts a significant economic strain on local fisheries as well as recreation and tourism-based River economies. In fact, NOAA estimates that the “Dead Zone” costs U.S. seafood and tourism industries at least $82 million a year. At a time when our River communities are grappling with multiple disasters, this is money we cannot afford to lose.

So, what does a smaller measured Dead Zone mean?

Every year, NOAA organizes a group of researchers to measure the precise size of the summer Dead Zone. This annual cruise only provides a snapshot of the Dead Zone frozen in time. It doesn’t capture its largest and smallest size, but instead reflects whatever the Dead Zone happens to be at the time of the cruise is its measured size. That means that throughout the summer, the Dead Zone may be bigger or smaller than the “snapshot” size reported by the annual cruise.

This year (and last year), the timing of the measurement cruise happened to coincide with a significant weather event: Hurricane Hanna. Big storms and hurricanes have the effect of churning up ocean water and reintroducing oxygen to depleted aquatic environments. While the effect of a weather event is temporary, the measurement is not.

What can we do about nutrient pollution?

From historic floods in 2019 to a global pandemic in 2020, we know that we must be doing more not less to support and invest in the resilience of River communities. For the good of the River and the Gulf of Mexico, 12 states along the Mississippi and Ohio Rivers formed the over two decades ago in 1997. The 12 member states on the Task Force have developed State Nutrient Reduction Strategies — plans for how each will reduce its own nutrient contributions to the Gulf of Mexico.

No one state on its own can solve the nutrient runoff problem in the Gulf of Mexico. Unfortunately, even with the state-by-state strategies ongoing, devastating Dead Zones and harmful algal blooms continue to be a problem year after year.

The Mississippi River Network continues to advocate for increased support for state nutrient reduction strategies through meetings with state, federal, and agency staff. Thanks to River Citizens like you, this past month the 1 Mississippi program sent decision-makers a public petition with over 500 signatures urging Congress to fully-fund proven solutions to reduce nutrient pollution.

We could all rally around something to celebrate these days, and a shrinking Gulf of Mexico Dead Zone created by reduced nutrient pollution in the Mississippi River Basin would certainly be an incredible accomplishment. Unfortunately, this year’s small Dead Zone measurement does not equal small pollution.

-Maisah Khan

Policy Manager, Mississippi River Network

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