Study: annual oxygen-starved Gulf of Mexico dead zone, caused by farm fertilizer runoff, will persist for decades

According to a study published in the journal Science, the annual "dead zone" in the Gulf of Mexico will persist for decades, which could hurt fishing industries and the communities that rely on them.

The 2017 Gulf of Mexico dead zone (NOAA map)

A dead zone is an oxygen-deprived area at the bottom of a body of water that appears after fertilizer runoff spurs the growth of algae. After the algae die, their decay uses oxygen faster than it can be brought down from the surface, possibly suffocating marine life. Last year's Gulf dead zone was a record 8,776 square miles, the size of New Jersey. It has appeared in the Gulf every summer since the National Oceanic and Atmospheric Administration began measuring it in 1985, and a similar one also forms in Chesapeake Bay.

"The study said that even if the runoff was completely eliminated, which isn't likely, it would still take at least 30 years for the area to fully recover. According to the study, nitrogen can move very slowly through soil and groundwater systems, meaning runoff from agriculture can take decades to eventually reach the ocean," Doyle Rice reports for USA Today.