There's a 'dead zone' in the Gulf of Mexico the size of New Jersey

"The dead zone in the Gulf of Mexico has been growing since the 1950s and 1960s, when much more fertilizer was applied to agricultural land and started going downstream and into the Gulf of Mexico. For the past 20 years, it has been fluctuating up and down. Most of that is due to differences in precipitation and river runoffs," said Robert Magnien, director of the Center for Sponsored Coastal Ocean Research at NOAA.

But the amount of rain is only part of the equation, Magnien said.

“This is not a natural phenomenon, but it is affected by variations in climate or weather patterns.”

"We are at a much different place than is natural. This is not a natural phenomenon, but it is affected by variations in climate or weather patterns," he said.