Earlier this year scientists forecast this summer’s dead zone — an area of oxygen-deficient water in the northern Gulf of Mexico — would be larger than ever.
Now that researchers have cruised the Gulf they’ve found that it wasn’t, although it was pretty large.
This year’s dead zone is 17,520 square kilometers, or 6,765 square miles. That is well below the forecast size of 9,400 sq. miles.
The chief scientist, Nancy Rabalais, said the winds and waves Tropical Storm Don mixed up the water column and helped disperse the waters with low oxygen.
Forecasters had predicted a large area of low-oxygen waters because of record-breaking floods from the Mississippi River, which delivered excess nutrients, particularly nitrogen and phosphorus, into the Gulf. These nutrients create large algae blooms which, upon decomposition, suck oxygen out of the water.
Dead zones are areas of this hypoxic water in which fish, shrimp and crabs are stressed and can sometimes die due to oxygen starvation.
Scientists also noted that discharge from the Mississippi River also fell off dramatically in July, which also may have led to a smaller-than-expected dead zone.
Another group of researchers, led by Steve DiMarco of Texas A&M University, will go back into the Gulf in August to again measure its extent. The cruise will help scientists understand how the dead zone evolves during the summer months.