More corn for meat and ethanol, less habitat for Gulf fish
by Tom Philpott.
Deep in the Gulf of Mexico, plumes of dispersed oil linger, wreaking unknown damage on one of the globe’s most productive ecosystems.
But
BP’s oil isn’t the only destructive substance that gushed into the Gulf
this year. This summer—and every summer since the early 1970s—a
large amount of fertilizer leached out of Midwestern corn fields and
into streams that drain into the Mississippi, eventually
making its way to the Gulf. Once there, it feeds gigantic algae blooms
that, as they decompose, suck up oxygen and squeeze out sea life.
Scientists call this process “hypoxia.”
Researchers
from Louisiana Universities Marine Consortium have been measuring the
Gulf’s hypoxic zone since 1985. Every year, they gauge the size of the
“dead zone” by heading out on a research ship called the Pelican to measure oxygen levels near the Mississippi’s mouth. The team has just filed its report [PDF] for this year. Their verdict: “one f the largest ever.”
The
team concluded that this year’s dead zone covers 7,722 square miles—
an area roughly equal to the landmass of Massachusetts, and the sixth-largest
area since the group started measuring. As the chart at the bottom of this post shows, this year’s dead zone fits in with a disturbing upward trend
since 2006, when government-mandated ethanol production began diverting
ever-greater amounts of corn into car-fuel production.
What
does ethanol have to do with the dead zone? Responding to higher corn
prices, farmers have been moved to shift more land into corn production
and use more chemical fertilizers to boost yields. Corn plants typically
only take up 40 percent of the synthetic nitrogen applied by farmers,
leaving the rest to wash out into streams and down to the
Gulf.
Last
year, the Gulf got merciful respite. Tropical storms came at just the
right time to diffuse fertilizer pollution, resulting in the smallest
dead zone since 2000. This year, recent storms have just broken the
hypoxic areas into clusters. As the report puts it:
Instead
of the usual continuous band of low oxygen along the coast, this
summer’s distribution was a patchwork of several areas. The scientists
think that this result is because of recent tropical storm activity.
And
this summer’s dead zone may actually be the largest ever—bad weather
stopped the Louisiana Universities Marine Consortium’s ship from fully
measuring the affected area. “The total area probably would have been
the largest if we had had enough time to completely map the western
part,” the consortium’s executive director, Nancy Rabalais, said.
The
researchers directly tie the size of the dead zone to industrial corn
production in the Midwest. “The size of the hypoxic zone and nitrogen
loading from the river is an unambiguous relationship,” one researcher
remarked. “We need to act on that information.”
Of
course, we’re doing the exact opposite. For the health of the Gulf ecosystem, researchers hope to see the size of the dead zone drop significantly by 2015. But ethanol mandates and surging demand from China all
but guarantee higher corn prices for years to come. And that means ever
more chemical fertilizers will be dumped on Midwestern corn fields—
and ever larger dead zones will bloom going forward. To supply the world with cheap
low-quality meat and and ourselves with highly subsidized, low-quality
fuel, we seem content to kill off ever larger swaths of a vital natural asset. We’re behaving not unlike a rich kid who blows his trust fund on Scotch, cocaine, and casino chips.
It also bears noting that nitrogen-fed dead zones like the one in the Gulf—the largest one of 400 worldwide—don’t just devastate local fish habitats. They also contribute to climate change. According to a study published this spring in Science, oxygen-starved areas of the ocean emit significantly more nitrous oxide into the atmosphere than healthy waters. Nitrous oxide is a greenhouse gas some 300 times more potent than carbon.
Related Links:
The Gulf’s invisible villain: natural gas
Philly chef gets his hands dirty for his farm-to-table restaurant [SLIDESHOW]
Looming storm delays BP battle to plug Gulf well
View full post on Grist – the latest from Grist