(The Center Square) − The Gulf of America's "dead zone" has shrunk significantly this summer, with scientists measuring a hypoxic area of just over 4,400 square miles — roughly a third smaller than last year and far less than the long-term average, federal officials announced Wednesday.

The dead zone, a stretch of oxygen-depleted water that forms annually off the Louisiana and Texas coasts, is caused primarily by excess nutrients washing into the Gulf from the Mississippi-Atchafalaya River Basin.