Ecocentric

This Year’s Gulf of Mexico Dead Zone Could Be the Biggest on Record

The dead zone in the Gulf of Mexico—a growing and shrinking region of oxygen-free water—could be the largest on record this summer, thanks to flooding and fertilizer runoff.

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NOAA

The dead zone, indicated in red, is filled with low to no-oxygen water, causing nearby fish to flee or die.

The near record-breaking Midwestern drought of 2012 shriveled corn crops and toasted pasture land. But it did have one positive side effect. The drought significantly reduced the size of the seasonal Gulf of Mexico dead zone. Less rain led to less fertilizer runoff—the dead zone is fed by a buildup of nitrogen-based fertilizer in the Gulf—which meant that the 2012 summer dead zone measured just 2,889 sq. miles. That’s still a zone the size of the state of Delaware, but it was the fourth-smallest dead zone on record, and less than half the size of the average between 1995 and 2012.

This year will be different. Heavy rainfall in the Midwest this spring has led to flood conditions, with states like Minnesota and Illinois experiencing some of the wettest spring seasons on record. And all that flooding means a lot more nitrogen-based fertilizer running off into the Gulf. According to an annual estimate from National Oceanic and Atmospheric Administration (NOAA) sponsored modelers at the University of Michigan, Louisiana State University and Louisiana Universities Marine Consortium, this year’s dead zone could be as large as 8,561 sq. miles—roughly the size of New Jersey. That would make it the biggest dead zone on record. And even the low end of the estimate would place this year among the top 10 biggest dead zones on record. Barring an unlikely change in the weather, much of the Gulf of Mexico could become an aquatic desert.


(MORE: Visualizing the Anthropocene)

The nitrogen nutrients that flow into the Gulf, especially during the rainy spring season, encourages the growth of explosive algal blooms, which feed on the nitrogen. Eventually those algae die and sink to the bottom, and bacteria there get to work decomposing the organic matter. The bacteria consume oxygen in the water as they do, resulting in low-oxygen (hypoxic) or oxygen-free (anoxic) regions in the bottom and near-bottom waters.

That’s what a dead zone—water, essentially, without air. Sealife—including the valuable shellfish popular in Gulf fisheries—either flee the area, much as you or I would if someone were to suck all the oxygen out of the room, or die. That’s why the dead zone matters—the larger it is, the greater the populations of fish that might be affected. With commercial fisheries in the Gulf worth $629 million as of 2009—and still recovering from the impact of the 2010 oil spill—the dead zone means business.

The major factor driving the size of the dead zone—beyond changing flooding patterns—is the use and overuse of fertilizers in America’s rich Midwestern corn belt. The U.S. Geological Survey estimated that 153,000 metric tons of nutrients flowed down the swollen Mississippi and Atchafalaya rivers during May—a 16% increase over the nutrient load average seen during the past 34 years. And as James Greiff of Bloomberg points out in a recent piece, those nutrients are used disproportionately to feed one particular crop:

The culprits behind the dead zone are many, but one deserves special attention: corn. Unlike, say, soybeans, which can grow without fertilizer, corn can’t grow without it. It takes 195 pounds of fertilizer to grow an acre of corn.

And the U.S. grows a lot of corn — more than any other country. What’s more, 40 percent of the U.S. corn crop is devoted to making ethanol, which fuel companies must blend with gasoline under a congressional mandate. The Gulf dead zone is yet another reason for Congress to kill that mandate.

A state-federal task force was actually set up in 2008 with the aim of reducing the nutrient flow in the Mississippi by 45% by this year—but as the numbers demonstrate, there hasn’t been much success. Farmers could be encouraged to use fertilizer more efficiently—Greiff suggests ending the practice of applying fertilizer to fields in the fall after crops are harvested, and instead laying it down in the spring. They should also limit the amount of water running off their land, much of which ends up in the rivers and then the Gulf.

Of course, Midwestern farmers care chiefly about the crops in their own fields, not what might be happening in the Gulf of Mexico, hundreds of miles downstream. (And the American farmer is just a bit more politically powerful than Gulf fishermen, let alone environmentalists.) But that invisible telecoupling is what make today’s environmental threats—climate change, ocean acidification, the wildlife trade—so devilishly complex. Just thinking about it is enough to suck the oxygen right out of the room.

(MORE: The New Science of Telecoupling Shows Just How Connected the World Is—For Better and For Worse)

78 comments
FormerEPAer
FormerEPAer

The problem was actually recognized much earlier and an Action Plan devised and submitted to Congress in 2001. Lack of $ and will have hobbled its implementation, along with the Fools Gold of corn-based ethanol as a fuel additive. Every politician looking at the Iowa Caucus genuflects at the altar of corn. The Gulf Dead Zone is just one of several undesirable consequences.

AbinicoWarez
AbinicoWarez

And what happens when the entire planet is a dead zone?

junktex
junktex

After the BP disaster,the Gulf is dying

PaulMueller
PaulMueller

If the algae is thriving on nitrogen, why aren't we harvesting the algae for fertilizer/compost. Looks like an opportunity to solve multiple problems

HilaryGroom
HilaryGroom

It's not just fertilizer, it's animal waste.  There is lots of phosphate in animal waste.  There's an obvious solution here, the suggestion to reduce meat consumption doesn't need anymore arguments for it.

Onepatriot
Onepatriot

Seems last year would have been a perfect time to try to deal with this since the waters were at low levels in the river and upstream.  So tired of seeing the inactivity in Washington in addressing any of the serious problems that we created, facing this beautiful  country.

I was under the impression that there were buffer zones required for these farmed fields next to streams.   Is anybody policing that? Or is that another voluntary compliance in lieu of , heaven help us, "regulations".  

alvarez.t3
alvarez.t3

B.P , Terrorist Oil Corporation killing our Oceans .

KatieGibson
KatieGibson

I think it's important that we note farmers aren't the evil ones in this situation. Yes this is a bad consequences directly related to their actions but to solve the problem we have to look a little wider. Farmers are often just attempting to survive life like most people. Just trying to keep their houses, land, families together. This is a systemic issue. We also have a tendency to instead of fix the systemic problem create a patched solution. Something that only fixes the whole that we created, instead of the bigger issues. It's gotta change at the top if you want the bottom to be different. 

jota511
jota511

Ah, those pesky "unintended consequences" of Congressional do-gooders. To those in Congress: It is better to do nothing and be thought a fool than to act and remove all doubt. (paraphrase of a quote by others).

OccamsRazor1349
OccamsRazor1349

"It takes 195 pounds of fertilizer to grow an acre of corn" . . . This is one reason (of many) why corn-based ethanol is a complete scam and waste of money.

PaperlessLess
PaperlessLess

Can Sea food from the dead zone be responsible for Republicanbigotism in the Bible belt?

drdev
drdev

Gaia Water Ltd has a technology can take oxygen out of the atmosphere and pressurize it into water.  This process is patented and can help solve dead zone areas related to algae.  www.GaiaWater.com

diad
diad

You forgot to mention how much of that corn is grown only to feed animals raised for human consumption.   Eat less meat, or no meat, if you want to make a difference.

Enjoyer
Enjoyer

Help me understand something. When there were millions of American Bison (buffalo) on the prairie of the central US, and all that excrement was washed down the Mississippi, didn't that also result in a dead zone? True, many of the sponges absorbing animal waste (aka swamps) are gone, but my bet it the nutrients from the buffaloes made it to the Gulf in huge quantities. Is there anything in the Gulf sediments that comments on this?

STS
STS

Shocking!!!!! F'ing BP blasts millions of barrels of oil into delicate ecosystem, then comes out with 'green' commercials, everyone completely forgets the massive catastrophe. What??? What the.....??

Then Japan nukes the Pacific Ocean a few weeks later. The planet is dying.

sciguybm
sciguybm

Really. Fertilizer.  Not the millions of tons of atrazine? Not the millions of tons of roundup? (yes, I said tons, not pounds) No, they blame fertilizers.  Well folks: that's why you are all getting cancer and your children are all gay. Enjoy.