I grew up in the riverport city of Memphis, Tennessee, and later lived further upstream in Northern Kentucky, a mile or two from the Ohio River. Whereas my wife (and other New England natives) are accustomed to having the ocean handy, I am used to having a giant river nearby that defines the early history of the towns along its banks. Rivers are the Appian Ways of the US.
MSNBC has a good article about the health of the Mississippi River, which is flushing an abundance of farmland topsoil and fertilizer and other fun stuff into the Gulf of Mexico.
The result is a giant “dead zone” of coastal water suffering from hypoxia, or oxygen depletion.
Algae, our little buddies, kinda like the nutrients in the runoff. As the algae grow and then die, they begin to decay – an oxygenation process that consumes the water’s oxygen faster than the water can absorbed more from the air. Then the fish can’t breathe. Hence “dead zone”.