Gulf of Mexico’s dead zone expands

July 12, 2008–Science News

RESTON, Va., July 12 (UPI) — U.S. researchers said heavy streamflows are sending record amounts of nitrogen and phosphorus into the Gulf of Mexico.
The U.S. Geological Survey said spring nutrient delivery from the Mississippi-Atchafalaya River Basin to the northern Gulf of Mexico was among the highest in the last three decades. Nutrient delivery is one of the primary factors controlling the size of the hypoxic zone in the northern Gulf of Mexico. Oxygen levels in the zone are too low to support most life.
Researchers said the amount of phosphorus going into the Gulf of Mexico is up 60 percent and the amount of dissolved orthophosphate going into the Gulf is up 85 percent. Nitrogen is estimated to be 40 percent higher.