It would cost $2.7 billion a year to reduce by two-thirds the size of the “dead zone” in the Gulf of Mexico through reductions in nutrient runoff, says a study published in the journal Proceedings of the National Academy of Sciences. The dead zone, blamed on nutrient runoff from the Mississippi River basin, is the second-largest in the world and lately has covered 15,000 square kilometers. A national task force has set a goal of limiting the hypoxic zone to 5,000 square kilometers.
According to an Iowa State University think tank that had a role in the study, scientists examined 550 agricultural subwatersheds to determine where it would be possible to get the greatest result per dollar of conservation investment. One of the ISU researchers, Catherine Kling said in a news release, “I was first struck by how small actions in thousands of agricultural fields could collectively contribute to such a large problem area.” The study did not suggest a source of funds for the work.