Ramping up ethanol production for alternative fuels will worsen the "dead zone" in the Gulf of Mexico, a stretch of water unable to support aquatic life, according to a report co-written by the University of British Columbia.
The U.S. Senate's recently announced plan to triple production of ethanol made from corn starch by 2022 will increase the zone by 10 to 19 per cent from the 20,000-square-kilometres — an area roughly the size of New Jersey — it has recently occupied, the report said.
"This rush to expand corn production is a disaster for the Gulf of Mexico," said Simon Donner, an assistant professor in UBC's geography department, in a statement. "The U.S. energy policy will make it virtually impossible to solve the problem of the dead zone."
The problem stems from the nitrogen and phosphorus found in agricultural fertilizer, which can cause excess growth of algae in bodies of water, the researchers said. When that algae decomposes, it can consume much of the oxygen in the water.
Fertilizer being used in much of the U.S. agricultural heartland, such as Illinois, Iowa, Nebraska and Wisconsin, is the primary source of pollution in the Mississippi River system, which drains into the Gulf of Mexico. Every summer, that nitrogen is deposited in the Gulf, where the dead zone forms.
Donner and Chris Kucharik of the University of Wisconsin came to their conclusions by combining agricultural land-use scenarios with models of terrestrial and aquatic nitrogen cycling. Their work appears in Monday's edition of the Proceedings of the National Journal of Sciences.
"The nitrogen levels in the Mississippi will be more than twice the recommendation for the Gulf," Donner said.
Boosting ethanol production without increasing the amount of nitrogen in the Mississippi will require "radical shifts in feed production, diet and agricultural land management," the report said.
Corn planting may have to be moved into other states or less of the crop would have to be used to feed cattle, which would also mean less meat consumption by people.