By any account, the Deepwater Horizon explosion and oil spill in the Gulf of Mexico in April 2010 was a disastrous event. Cleaning up required an infusion of cash to the tune of billions of dollars within a few months.
Now consider the “dead zone” phenomenon in the same body of water. It’s a disaster in its own right, but a far more subtle one that doesn’t involve fire, smoke, oil slicked water – nor unfortunately, billions of dollars for remediation.
And that’s a problem that weaves together clashing interests across multiple states and the fisheries down south.
During fall and spring, farmers apply nitrogen-based fertilizers to their crops. The excess nitrates pour invisibly into the Mississippi River and spill into the gulf. It’s a feast for algae, which thrive on the nitrogen compounds. But the decomposition of the massive algal bloom depletes oxygen in the water.
Animals that can’t escape the area die. Fish swim away, hurting the seafood industry. The annual event generates a few media stories and then fades away until the next year.
This is not a new phenomenon. The National Oceanic and Atmospheric Administration has been mapping the zone since 1985. State and federal agencies have implemented programs over the years to stem the flow of nutrients.
What is surprising is that years of such efforts have not paid off. In 2013, the dead zone was the size of Connecticut, which was smaller than experts had predicted but three times larger than the goal set by an Environmental Protection Agency task force in 2001.
Mark David, who has been studying agriculture and water quality in Illinois for two decades, wanted to know why.
After evaluating the situation, he found that while small programs have some effect, larger forces overwhelm local benefits. His report appears in the ACS journal Environmental Science & Technology.
“In the big scale of things, we’ve done very little,” says David. “In some ways, we’re going in the opposite direction with more corn and more drainage.”
When farmers first settled in the Midwest, David explains, though the land was extremely fertile, it was also extremely wet. Plows would get stuck in soggy ground. To make the land more crop friendly, they buried one-foot long clay pipes, or tiles, to redirect the excess water from the fields. The effect was dramatic. The land yielded bountiful harvests on some of the best agricultural soil in the world.
But along with the excess water, the tile system flushes out nitrates from fertilizer. And the drain is the mighty Mississippi.
With demand high for biofuel, corn pays very well these days, David says. Now, tens of millions of acres from southern Minnesota to Ohio are on tile drainage, contributing a constant flow of nitrates each spring into the river, he adds.
“We want clean water, but we’re doing everything possible to maximize corn and soybean production,” David says. “And corn and soybean production on tile-drained land is about as leaky a system as you can have.”
To compound the problem, David says, farmers have few incentives to mitigate run-off. Planting specific winter crops, called cover crops, that improve soil quality and retain nitrogen would cost farmers an additional $30 to $40 per acre. Woodchip bioreactors — enclosed beds of woodchips — placed at the end of field drainage pipes remove nitrates but cost around $8,000 each.
“I think we know how to reduce nitrates,” David says. “It involves working more closely with farmers. But many practices that reduce nutrients don’t increase profitability. Somewhere we need to figure out how we’re going to pay for the practices that improve water quality but don’t boost yields.”
Is it time to boost the level of federal involvement? If so, what role could government play? What non-government actions could be taken?
“Biophysical and Social Barriers Restrict Water Quality Improvements in the Mississippi River Basin”
Click here for the abstract.
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Image credits: American Chemical Society (top), Jupiterimages/Photos.com/Thinkstock (bottom)
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