Earlier this month, NOAA forecast that this summer in the Gulf of Mexico an area the size of Delaware and Connecticut combined would have so little oxygen that marine life flees from it or dies in it. In 2017, this “dead zone” was the size of New Jersey, the largest one ever recorded.
On the heels of this year’s forecast, acting director of NOAA’s National Ocean Service, Nicole LeBoeuf, noted that the Gulf dead zone doesn’t just hurt marine life—it “puts a strain on the region’s living resources and coastal economies.”
The annual dead zone has shown no signs of significant shrinking over the last three decades, despite years of research and investments in analyzing the problem and identifying solutions. Yet, a winning and achievable solution has been staring us in the face all along: farming practices that are good for the soil, good for our waterways, and quite possibly better for addressing the climate crisis.
Our team decided to tackle the dead zone problem head-on in our new report “Reviving the Dead Zone: Solutions to Benefit Both Gulf Fishers and Midwest Farmers”. Our analysis in the report reveals that shrinking the Gulf of Mexico dead zone, by providing Midwest farmers with more support to use science-based healthy-soil practices, could yield large economic, environmental, and social returns for the Gulf. Our analysis starts to put a dollar value on these returns.
How does agriculture contribute to the Gulf dead zone?
For over 30 years, this dead zone has appeared each summer—and reappeared, over and over again—due in large part to millions of tons of nitrogen pollution in the Mississippi and Atchafalaya rivers, both of which empty into the Gulf of Mexico. Nitrogen naturally occurs in rivers, lakes, streams and oceans, and it is necessary for plant and animal growth. But too much of it can disturb the ecological balance of such environments. In bodies of water, excess nitrogen can deplete oxygen levels, or worse, result in hypoxia. Hypoxic areas are commonly referred to as dead zones. Our report summarizes the many studies that have found that marine species flee from or die in dead zones. Two species that are commercially important to the Gulf fishing industry, shrimp and a small fish called menhaden, are particularly hard hit by the Gulf dead zone.
Where does the nitrogen that causes dead zones come from?
Much of the nitrogen pollution in the Gulf comes from upstream, having washed off farms in the Midwest. For example, nitrogen is necessary for crops to grow, and farmers—including those growing corn in the “Corn Belt”—often use large amounts of it to encourage high yields. In aggregate, our report estimates that corn and soybean farmers whose land is within the Mississippi and Atchafalaya watersheds applied 114 million tons of synthetic fertilizer nitrogen since 1980. It has been estimated that 41 percent of the nitrogen pollution in the Gulf is attributable to farm fertilizer use.
Nitrogen fertilizer use is unfortunately a mixed bag. Even though it helps crops grow, its use has some serious environmental side effects. This is because many nitrogen-based fertilizers dissolve readily in water, making them available to plants but also allowing them to easily wash off farms and into streams and rivers during rainstorms. Nitrogen from fertilizers also leaches through the soil and into underground aquifers that store our drinking water.
The predominant way in which farms are managed today makes it even easier for nitrogen to wash off into waterways. In fact, roughly a third of all fertilizer nitrogen applied to US crops leaves the farm field and enters our waterways. Our analysis estimated that 31 million tons of fertilizer nitrogen applied to corn and soybean farms in the Midwest has made its way into the Mississippi and Atchafalaya river watersheds since 1980. Much of this nitrogen ultimately ends in the Gulf of Mexico, where it fuels the annual dead zone.
Nitrogen losses from Midwest farms are damaging the foundation of the Gulf fishing industry
As our report shows, according to data from the National Oceanic and Atmospheric Administration, Gulf commercial and recreational fishing industries generated $57 billion in economic impact and 200,000 jobs for the region in 2016. In the same year, shrimp caught in the Gulf was worth $412 million. According to NOAA, the Gulf of Mexico is the most economically important fishery in our country.
But this industry isn’t just about dollars. Shrimping in particular is the cornerstone of the diverse Gulf community’s way of living. For example, nearly one-quarter of Louisiana’s shrimpers are Vietnamese refugees. And members of the United Houma Nation—a Native American tribe in Southeastern Louisiana with deep ties to the water—have been pulling shrimp and fish from the Gulf for generations. We have the Houma to thank for the delicious shrimp file gumbo, a now-classic Cajun dish.
Today the shrimp industry faces many challenges and the dead zone is one of them. When it forms, the dead zone overlaps with the natural habitat of commercially important shrimp species. Naturally the shrimp attempt to move out of the area, which in turn makes it harder—more fuel, more time out on the boat—to harvest enough shrimp to make a living. Increases in shrimp imported to the US have also put pressure on the industry for decades, putting many boats out of business altogether. In our report, we show that the number of commercial shrimp trawl licenses issued in Louisiana has declined rapidly over the last few decades.
Finally, our report also describes in greater detail how the dead zone has affected a variety of marine life in its vicinity over the last four decades, and how in turn this causes damage to the ecosystem services—economically important services that the environment provides for humans, such as food production—provided by fisheries and marine habitat that are the foundation of the region’s fishing industries.
We must revive the dead zone and protect Gulf Coast fishing industries. Here’s how.
One way to shrink the Gulf dead zone is to reduce the amount of nitrogen that washes off Midwest farms. This could be done through widescale shifts in agricultural practices in the Midwest. We recommend science-based healthy soil practices that improve farm soils and reduce the amount of nitrogen that washes downstream.
Studies have found that shifting agricultural practices at the needed scales will be costly—up to $3.1 billion. However, our new analysis makes the case that shrinking the dead zone could generate a major return on this investment in the Gulf.
We evaluated multiple scenarios in which wide-scale adoption of healthy soils practices in the Midwest could reduce nitrogen losses that fuel the Gulf dead zone. We found that in these scenarios the economic damage caused by nitrogen pollution to Gulf fisheries and marine habitat could be reduced by between $34.4 million and $990 million (2018 dollars) annually. Reducing the damage that the dead zone causes to the ecosystem services in the Gulf could generate many benefits for the Gulf fishing industry, making it easier for the industry to cope with other intertwined environmental and economic stressors, including climate change. So, while it will be costly—to the tune of up to $3.1 billion annually for the federal government—to shrink the dead zone through improvements to Midwest agriculture, a large portion of these costs could be recouped by the Gulf fishing industry.
Besides showing the return on investment from adoption of healthy soil practices in the Midwest, our report offers recommendations that can help policymakers tackle the dead zone problem in a way that doesn’t pit farmers and fishers against one another. We believe that there is a way for both of these two critically important food production industries to thrive, for generations to come.