The Black Sea is a historically important one when it comes to deadzones. At its worse during the 1970’s-80’s the black sea ecosystem collapsed. The collapse was due to several factors, the most major being massive amounts of nitrogen (in the form of fertilizer) being injected into the system, leading to the collapse. From that collapse an estimated 60millon tons of organisms were lost, 5 million of which were fish. Resulting economic impacts were huge, losses in the fishing and tourism industries totaling near 2.5 billon.
Then came the collapse of the Soviet Union, and with it huge reduction in fertilizers. Recently because of the complete turnaround in environmental strains the black sea deadzone is almost nonexistent.
The Black Sea’s history is a poignant one, highlighting the direct relation between farming practices, environmental degradation, and subsequent recovery. Hopefully, with this historical example, places like the Gulf of Mexico, or the Mediterranean Sea, history will not repeat itself, and the environments/people will not have to go through such wrenching calamity.