The numbers are in. The 2020 Gulf of Mexico Hypoxic Zone, or Dead Zone, an area of low oxygen that can kill fish and marine life near the bottom of the sea, measures 2,116 square miles. This is the 3rd smallest dead zone in the Gulf since mapping of the zone began in 1985.
It begins innocently enough. Farmers use fertilizers to increase the output of their crops so that we can have more food on our tables and more food to sell to the rest of the world. But it is this agricultural runoff combined with urban runoff that brings excessive amounts of nutrients into waterways that feed the Mississippi River and starts a chain of events in the Gulf that turns deadly.
These nutrients fuel large algal blooms that then sink, decompose, and deplete the water of oxygen.
This is hypoxia - when oxygen in the water is so low it can no longer sustain marine life in bottom or near bottom waters - literally a dead zone.
When the water reaches this hypoxic state, fish and shrimp leave the area and anything that can't escape like crabs, worms, and clams die. So, the very fertilizers that are helping our crops are disrupting the food chain and devastating our food sources in the ocean when applied in excess. If the amount of fertilizer, sewage, and urban runoff dumping into the Gulf isn't reduced, the dead zone will continue to wreak havoc on the ecosystem and threaten some of the most productive fisheries in the world.