Gulf of Mexico ‘dead zone’ to be larger than average, but not near record

High rivers and high levels of nitrogen and phosphorus from farm and urban run-off mean a larger than average oxygen-starved “dead zone” is likely this year in the Gulf of Mexico, researchers said Wednesday.

But the predicted area for an area with too little oxygen for marine life is nowhere near a record, the National Oceanic and Atmospheric Administration said in a news release.

“Each year, the forecasts are reported to be bigger or smaller than some long-term average, when in fact the long-term average is not acceptable,” Don Scavia, professor emeritus at the University of Michigan School for Environment and Sustainability and one of the scientists who works on the forecast, said in a news release.

“We can’t control the weather; keeping nutrients out of streams and rivers should be our focus,” Nancy Rabalais of the Louisiana Universities Marine Consortium, who has been mapping the dead zone since 1985, said in an email.

The area forms every summer off Louisiana and stretches into Texas waters, starting at the sea floor and extending upward. It’s created as calm weather lets fresh river water form a layer above the denser salt water in the Gulf of Mexico. Fertilizer and other nutrients in the fresh water feed algae, which die and then decompose on the sea floor, using up oxygen.

This year’s low-oxygen area is expected to cover about 17,350 square kilometres, NOAA said in a news release.