Every summer, a “dead zone” forms in the Gulf of Mexico. Plumes of oxygen-robbing algae, fed by excess nitrogen coming in from the Mississippi River, kill off marine life and threaten the livelihoods of those who fish the Gulf. States bordering the Mississippi River are putting strategies in place to limit nitrogen from wastewater treatment plants, surface runoff, and agricultural fields. In a new study, University of Illinois scientists have estimated that a new conservation practice known as saturated buffers could reduce nitrogen from agricultural drainage by 5 to 10 percent.