It’s bad enough what marine “Dead Zones” do to the oceans; now it looks as if they’re drivers of global warming as well.

In a new report in the March 12 edition of the journal Science, Dr. Lou Codispoti of the University of Maryland Center for Environmental Science found that as Dead Zones expand, they release more nitrous oxide — a particularly potent greenhouse gas. As reported in US News and World Report:

“As the volume of hypoxic waters move towards the sea surface and expands along our coasts, their ability to produce the greenhouse gas nitrous oxide increases,” explains Dr. Codispoti of the UMCES Horn Point Laboratory. “With low-oxygen waters currently producing about half of the ocean’s net nitrous oxide, we could see an additional significant atmospheric increase if these ‘dead zones’ continue to expand.”

For more than 20 years, scientists have documented the appearance of a summertime Dead Zone that all but obliterates marine life in what is arguably the nation’s most important fishery, the Gulf of Mexico. Each year the Dead Zone grows to an area that is roughly the size of New Jersey – ranging from 5,000 to 8,000 square miles. The main culprit: an annual flood of excess fertilizer and animal waste from heavily farmed land running off into rivers and streams and finally into the Gulf, where it feeds the growth of massive algae blooms. The algae then die and decompose, robbing the water of oxygen and suffocating all life that cannot get out of the area.

The past decade has been especially bad for the Gulf Dead Zone, as federal mandates for ethanol fuel and robust commodity subsidies spurred the planting of millions more acres of fertilizer- and pesticide-intensive crops. Corn ethanol is an especially troubling contributor to the Dead Zone, and to the resulting nitrous oxide emissions, since we’re told that the subsidies and mandates for corn ethanol are there because of its potential to reduce greenhouse gases. Hmm. That’s not really working out too well, is it?

That raises two questions: Did the Environmental Protection Agency (EPA) factor in Dead Zone emissions from corn-ethanol runoff into its full life cycle analysis of ethanol in the RFS 2? If not, do they plan to?

Coupled with budget cuts that are dropping millions of protected acres from the Conservation Reserve Program, which helps mitigate agricultural runoff damage, the Gulf Dead Zone becomes the poster child for misguided government priorities: no money for conservation, but plenty of taxpayer cash to support the folks who cause the problem.

To make things worse, the most promising tool for shrinking the Dead Zone is the Environmental Quality Incentives Program (EQIP), which unfortunately has also been repeatedly targeted for cuts even as ethanol mandates and bloated commodity subsides remain unchanged.