Gulf 'Dead Zone' forecast to cover area 3 times Delaware's size

This summer's Gulf of America "dead zone" is forecast to span 5,574 square miles — about three times the size of Delaware, per National Oceanic and Atmospheric Administration.

Why it matters: Large dead zones destroy habitat for species vital to both the Gulf ecosystem and the U.S. seafood and tourism industries.

Context: The recurring low-oxygen area, fueled by nutrient pollution from farms and cities in the Mississippi-Atchafalaya watershed, appears each summer and threatens marine life and coastal economies.

• This year's size is about average.