The us demand for corn-based ethanol could cause nutrient-pollution in the Gulf of Mexico, expanding its dead zone, say scientists.

The dead zone forms in the Gulf of Mexico every summer when oxygen levels in the water become too low to support marine life. The condition arises when the Mississippi and Atchafalaya rivers empty nutrient-rich waters into the Gulf.

Researchers from Canada and the us used computer simulation to show the effect of biofuel production on nutrient pollution in aquatic system. Meeting the biofuel goals of the us for 2022 would increase nitrogen pollution in the rivers by 10-34 per cent. Nitrogen-based fertilizers are heavily used in corn fields. This will increase the size of the Gulf's dead zone, they said.