Dead Zone (IMAGE) Penn State Caption Last year, the dead zone in the Gulf of Mexico, one of the globe's most productive fisheries, was about the size of Connecticut. It results, primarily from the runoff of excess nutrients such as phosphorus and nitrogen from agriculture. Credit NOAA Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.