Corn ethanol production is killing the coastal Gulf of Mexico

Today’s recipe is for “Gulf of Mexico Dead Zone”:

  • Start with historically massive agricultural input of phosphorus and nitrogen into the Mississippi River system.
  • Add occasional yearly floods that can double the input of phosphorus and nitrogen following the flood.
  • Dump the Mississippi River into an algae-rich Gulf of Mexico.
  • Heat the Gulf water to a tepid 70 degrees Fahrenheit (local water temperatures may vary)
  • Add lots of sunlight.
  • Wait for phytoplankton algae bloom to form, then die and start decomposing.
  • Ta da! You’ve finished your Gulf of Mexico Dead Zone!
  • If you wish increase the size of your dead zone, just increase agricultural runoff from nitrogen fertilizers. Corn farming for ethanol would be a great way to start.

The Gulf of Mexico is one of the United States’ most important fisheries, where 72% of U.S. harvested shrimp, 66% of harvested oysters, and 16% of commercial fish are harvested for U.S. markets. But in 1985, a “dead zone” largely devoid of seabed marine life like shrimp and oysters was discovered along the Louisiana coast. Scientists determined that the ultimate cause of the dead zone was algae blooms fed by human agricultural practices, especially fertilizer runoff from corn.

As I alluded to above, nitrogen and phosphorus run off fields and are deposited by air into the Mississippi River where they flow downstream into the Gulf of Mexico. There, nitrogen and phosphorus provide so many nutrients to algae that they reproduce prolifically (bloom) until the available nutrients are all exhausted. Then the algae all die, sink to the bottom, and begin to decay. And as the algae decays, its pulls dissolved oxygen out of the water around it, reducing the amount of oxygen available for other marine life to live on. And so the area under and around the algae bloom dies from suffocation.

Now, with misguided corn ethanol biofuel subsidies available from the federal government, more acreage of corn is being planted than has been planted since WWII. The problem is that corn is horribly inefficient at using nitrogen fertilizer, and commercial corn cultivation is the single largest source of nitrogen in the Mississippi River. In 1999, the USGS released a report on the Gulf of Mexico dead zone (“hypoxic region”, meaning oxygen-poor) using the latest science available at the time. The report’s Topic 3: “Flux and Sources of Nutrients in the Mississippi–Atchafalaya River Basin” was a detailed examination of the types and sources of nutrients, and it found that approximately 35% of the nitrogen flowing in the Mississippi River came from two states representing only 9% of the the entire Mississippi River basin – Iowa and Illinois.

According to the National Corn Growers of America 2007 World of Corn site (latest production data is for 2006), these two states account for almost 40% of the nation’s annual production of corn, and according to AgriView, corn production is estimated to be 25% higher this year than last, or 13.3 billion bushels in 2007-2008 vs. 10.5 billion in 2006-2007. In the period measured by the USGS, 1980-1996, the average nitrogen flux was 1.3 million metric tons of nitrogen, 35% of which came from Iowa and Illinois. Over the same period, the average amount of corn grown in the US was 7.6 billion bushels, or just less than half of the estimated number of bushels for this year. If we assume that about the same proportion of nitrogen will go into the Mississippi River this year as did back then (this is my attempt to roughly account for improvements in agriculture since 1996), then the total nitrogen released this year will be approximately 2.28 million metric tons, or 1.75x the average from 1980 to 1996. And the 1980-1996 nitrogen measurements were already 30% higher than measured historical values from 30 years previously – the new values are 228% higher than historical values.

The dead zone in the Gulf of Mexico is already about 7,000 square miles, and while that’s not the largest area on record, if we continue to dump multiple megatons of excess nutrients from our cornfields into the Mississippi River, we’ll eventually kill off one of our most valuable fisheries in the process. Unfortunately, it’s likely going to come down to a tradeoff between politically expedient corn ethanol subsidies for Iowa and Illinois and the economic benefits of a viable fishery for Louisiana and Mississippi.

Thanks to Mike “Ubertramp” Pecaut for forwarding this one on.

[Crossposted: The Daedalnexus

21 replies »

  1. Great post. We live on the Gulf and have noticed an increase in red tides, which some attribute to excess nitrates and phosphates that have seeped into our waters.

    Good take on the unnecessary bio fuel supbidies. That’s just the way that the government gets to subsidize Archer Daniels Midland(ADM). The long term ramifications of that subsidy and the increased corn acerage(at the expense of wheat and soybeans) has yet to be felt. People are going to be without bread next year, as wheat stocks are at all time lows. In fact, one would have to go back to 1879 to see a smaller world wide supply of wheat, expressed as bu/person. Even with reduced acerage in wheat, the media has ignored the fact that the world wide wheat crop has been dismal this year, and doesn’t look good for the spring crop either. Expect the price of a loaf of bread to go up in price pretty soon.


  2. Generally speaking I’m not a fan of biofuels these day, not because they can’t work, but because they only make sense in certain circumstances. Ethanol will work if you do it right (cellulosic), but turning food into fuel is just plain wrong on several different levels. There are better ways to wean the U.S. off oil imports that don’t require drilling in previously closed public lands and that doesn’t require turning food that could feed Africa into a gasoline substitute.

    And if you start talking a pure global heating calculation, it’s pretty likely that corn ethanol is worse for carbon dioxide emissions than gasoline is. We don’t have a weed grass that we can convert into ethanol like Brazil does (sugar cane), so we’ll have to wait for industrial-scale algae conversion or cellulosic conversion of hardy native grasses. If we want to subsidize agriculture in the US for oil replacement, both of those projects would be far better uses of our taxes.

  3. Brian said: “Turning food into fuel is just plain wrong on several different levels.” You’re so right on so many different levels. The area the government needs to subsidize is on an efficient conversion of cellulose to ethanol…all types of cellulose. Converting corn to ethanol, except for some good corn whiskey, is pretty lame and not an efficient process at all. Oh well, ADM is happy, and their shareholders are doing well as the price of that giant processor has tripled in the past couple of years.

    Florida, and the entire Gulf region is well suited to sugar cane production. The only problem with sugar cane is the low price of sugar, which goes for around $0.10/lb. Farmers don’t want to plant cane, as it’s very labor intensive and yields a poor return on investment. Sugar cane is also very polluting because they burn off the cane. We know when they’re burning off the cane fields because we smell it over here and there’s a real haze. The closest cane fields from my house are about 50 miles away, and their burning affects our air quality significantly.


  4. Not only is corn an inefficient fuel crop, it is an inefficient crop in general. That we use corn to feed livestock is as bad, or worse, than using it for ethanol. Cows don’t eat corn, they can’t digest it; many of the evil things that are giving to cows (and to us) are so that the cows can digest corn. At least a few people may have noticed that we don’t digest corn very well either, but it is the building block of the entire food industry.

    What the post does not point out is that yield/acre is actually going down. Corn yield has gone up of late only because farmers have planted it instead of other crops. There is trouble brewing in our food supply. One poster commented about low supply for other agricultural commodities, this is true. The summer of ’09 may be a terrifying few months. Last year, beekeepers were spending millions to replenish hives just to get through the pollination season. If there is a further collapse of those populations in ’09, we can expect massive crop failures.

    I would suggest learning to garden, and doing it seriously this summer. The days of being able to count on the grocery store may well be numbered….

  5. The runoff matter and the algae blooms will fill up the Gulf of Mexico eventually, creating wonderful dry land, or mysterious marshes full of alligators. It will be so delightful and St. Louis won’t have to worry about sinking or being flooded. Don’t you want a larger contiguous land mass for the United States, you Gloomy Guses??

  6. I covered the food price story in my weekly newspaper column – and the food shortage is off the back of the largest ever food crop in recorded history. Around half the shortage is being attributed directly to ethanol-corn subsidies in the US.

    As I said in my column, using public money to raise the price of a commercial good and lead to inflation and shortages is piss-poor economic policy.

  7. Whythawk – no shit it’s piss-poor economic policy. But in a presidential election year, no-one wants to piss off Iowa (which alone grows something like 8% of the world’s entire corn harvest every year). Just look at the ongoing biofuel subsidies in the newest energy bill.

    I, on the other hand, have no such compunctions against pissing off Iowans.

  8. Whythawk said: “and the food shortage is off the back of the largest ever food crop in recorded history.” When was that? The wheat crop this year has been a near failure all over the world. Spring wheat doesn’t look too good either.

    The public money isn’t raising the prices of corn, it’s the demand side that’s raising the prices of all of the grains. The weak dollar is also driving our grain exports which continue at a brisk pace. I’ll agree that the subsidies are causing growers to switch to corn, but $11.00/bu wheat and $13.00/bu soybeans will bring back a lot of acerage to those crops. After all, we’re in a bull market for the entire grain complex, and all of the prices are going to rise, subsidies or not.


  9. Jeff, there is a set amount of agricultural land. Because of the nice corn subsidies many wheat farmers have changed crops. As such there is less wheat being farmed. Any crop failures (and there are always some places that are going to get it in the neck weather, or otherwise) is going to have a greater impact if there is less available. The OVERALL production of food has increased, it is just some crops that vary.

    Again, blame those subsidies.

  10. Yet another reason for nationwide electoral reform–the current system compels politicians to insert pork in legislation that favors powerful primary states, even at the long-term cost of food scarcity and environmental destruction.

    It’s all connected.

  11. Jackpine – According to the World of Corn 2007, the yield per acre peaked in 2004 but was higher in 2006 than in 2005. Estimates from Iowa State in August showed 180 bushels/acre, a huge jump. Of course, this is probably due to planting more corn plants per acre, but even by that account, yield per plant has been trending upward since 1992. I’m curious where you’re getting your data.

    Martin – To be fair to the feds, whole corn exports were a $7.1 billion business in 2006 (according to the 2007 World of Corn reports, and that doesn’t even include exports of corn syrup, corn starch, and other corn products. The total value of kernel corn in 2006 was about $33.7 billion. Corn is huge business for the U.S., so there are valid reasons to keep the industry healthy. The question is whether it needs the subsidies that it gets to keep it healthy. In my opinion, the answer to that one is a most emphatic “no”.

  12. What the US really needs to look into if it wants to subsidize biofuel production is bamboo which is one of the best producing crops in the world per acre and which we already have the technology to turn most of plant into fuel as apposed to a small portion of it as with corn.

  13. Whythehawk,

    According to the Minneapolis Grain Exchange research department (Full disclosure: I am a member of that exchange), our world wide grain stocks are at an all time low expressed as a percent. Our supply of wheat and corn is measured in weeks today instead of months or years in past seasons. Production has actually decreased per capita. The Ukraine had a poor wheat harvest, as did South America and Australia. The US crop came in late, and the yield wasn’t very good, and the protein content was below average. The Hard Winter wheat crop is pretty dismal, and Spring wheat doesn’t look much better and one look at the market prices will confirm this.


  14. Great post and very interesting calculations regarding the increased nitrogen fluxes. Please note though that while the 2007 nitrogen flux is estimated at 228% higher than historical averages, the size of the Gulf of Mexico hypoxic zone “is not the largest area on record”. If nitrogen flux was so important, it seems like this year would be the largest hypoxic zone recorded. Obviously, nitrogen is not the only factor in creating a hypoxic zone. Freshwater is less dense than sea water, so when a river empties into the sea, the freshwater “floats” on top of the seawater until it is mixed by waves and currents. This freshwater layer is kind-of like putting a lid on the underlying seawater, preventing atmospheric oxygen from penetrating. The “dead zone” is usually just a very small layer of water a few feet deep near the bottom. I think nitrogen influxes and the subsequent algae blooms and die off/decomposition is important, but naturally occuring processes are also extremely important in creating and sustaining Gulf hypoxia.