Study: 'Legacy' nitrogen also feeds Gulf of Mexico dead zone
NEW ORLEANS (AP) - Canadian scientists say the Gulf of Mexico's annual "dead zone " will likely persist for decades.
They say the oxygen-starved patch would linger even if farmers could immediately end all fertilizer runoff. A zone with too little oxygen to support marine life forms every summer, fed largely by nitrogen fertilizer.
A study in Thursday's Science journal says it's not just the current year's fertilizer adding nitrogen to the Mississippi River, but nitrogen that has built up underground and in groundwater. Researcher Kim Van Meter says reducing the dead zone will take work, and planners need to realize how long it will take.
Dead zone researchers not involved with Van Meter's work say it's a well-done study. They also note that the zone responds quickly to changes in nitrogen in the river.