Scientists Warn: Largest Ocean 'Dead Zone' in History

The largest ‘dead zone’ ever recorded is headed for the Gulf of Mexico this summer, as high levels of pollution runoff, elevated by Midwestern floods, seep into the ocean.

The dead area could grow to as much as 8,500 square miles of toxic deep ocean water—killing all marine life in its path—warn National Oceanographic and Atmospheric Administration scientists.

The findings signal a warning not only about the Gulf of Mexico, but about the many dead zones that develop each year across the world’s oceans.

Dead zones emerge deep beneath the marine surface when pollution runoff from farms seeps into the ocean, releasing nitrogen that feeds large algae growths.

When areas become over-grown with algae because of excess nitrogen, they become depleted of oxygen and thus toxic to marine life, choking and killing fish in a process scientists call ‘hypoxia.’

“Dead zones are becoming more common worldwide in areas where coastal waters are swamped with nutrients, particularly nitrogen, from sewage or fertilizer,” NOAA scientists explain.

This year’s runoff is especially bad, because heavy rains and floods this spring are flushing Midwestern farm pollutants into the ocean.

The Gulf of Mexico dead zone is expected to swell far beyond its usual 18,000 kilometers, alarming scientists.