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Sunday, May 9, 2021: Gulf of Mexico Dead Zone


Sunday, May 9: Tomorrow I am going to explain nutrient farming and how beavers are going to help save our planet, but today I'm going to give you a little background about how we got here.

Illinois used to be a quarter wetlands before European trappers arrived and trapped all the beavers. The beavers kept the ground nice and soggy because they kept rivers connected to their floodplains. Rivers looked completely different; they meandered, hopped, and circled back on themselves. Once the beavers were gone, the rivers became cut off from their floodplains.

Farmers settled in Illinois and decided they would build levees to pump the remaining water off of their fields. The rivers became much more constrained, moved faster, and caused more erosion. The farmers farmed the soil until it became poor, and then the farmers had to start adding fertilizers to the soil so that food would grow—fertilizers that contain the nutrients nitrogen, phosphorus, and potassium


The fertilizers wash into the rivers in Illinois--the Illinois River, the Kankakee River, and the Sangamon River, to name a few. Those rivers are tributaries of the Mississippi River. And because the rivers move so quickly now, and because there isn’t enough wetlands, there’s no chance for the fertilizers to be filtered out and purified by wetlands.


Then the Mississippi River carries all of those fertilizers into the Gulf of Mexico. And the nutrients in the fertilizers cause large algae blooms to develop, depleting the dissolved oxygen in the area and causing a giant dead zone in the Gulf of Mexico where nothing can live. The dead zone threatens seafood production, recreation, and marine life. Which is bad.


The agricultural states whose rivers feed into the Mississippi River know this is an enormous problem. The Illinois Department of Agriculture releases a Nutrient Loss Reduction Strategy biennial report to discuss efforts to reduce the amount of fertilizer that is entering our rivers. Strategies discussed in the 2019 report include growing cover crops, reducing the amount of fertilizer, and “constructed” wetlands--but the number of acres under “constructed” wetlands is relatively very low. There are a number of federal and state programs aimed at helping farmers reduce the amount of fertilizer entering our rivers. But there’s a cutting edge strategy that is being adopted out west to solve water quality problems that isn’t mentioned in the 2019 report. And that strategy is called “low-tech, process-based river restoration.”


Low-tech process-based restoration basically means finding or creating a location along a degraded river that would be a suitable habitat for beavers, relocating beavers to that location, and letting them work their wetlands-creating and water-purifying magic. It costs a fraction of conventional restoration. The resultant wetlands prevent flooding, improve water quality, and absorb the nutrients, preventing them from entering the river system. So farmers could allow wetlands to be reclaimed along the rivers, and it would go a long, long way toward addressing the problem of agricultural runoff creating a dead zone in the Gulf of Mexico.

But wait, there's more! Tune in tomorrow.

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