This year’s flooding in the Corn Belt will lead to a larger dead zone in the Gulf of Mexico.
The National Oceanic and Atmospheric Administration says the abnormally high amount of spring rainfall in many parts of the Mississippi River watershed led to record high river flows and much larger nutrient loading to the Gulf of Mexico.
The Mississippi River watershed drains 1.2 million square miles, including all or parts of 31 U.S. states and two Canadian provinces.
The excessive amount of runoff, along with its contents, is slowly mixing fresh water with salt water, creating the uninhabitable space for marine life.
NOAA says the annually recurring Gulf of Mexico hypoxic zone is primarily caused by excess nutrient pollution from human activities, such as urbanization and agriculture.
Once the excess nutrients reach the Gulf, they stimulate an overgrowth of algae, which eventually die, then sink and decompose in the water.
The resulting low oxygen levels near the bottom are insufficient to support most marine life.
