What causes the Dead Zone?
The Dead Zone in the Gulf of Mexico is caused by human activities in the upstream Mississippi River watershed, and enhanced by natural changes in the environment and climate or weather. Contributors include nitrogen fertilizer, animal manure, atmospheric deposition as a result of automobiles and fossil-fueled power plants, and waste. Farmers spray their land with pesticides and other types of fertilizers, in order to protect their crops. When it rains, soil is washed off the farms and into nearby rivers and bodies of water. The farm runoff includes animal manure, fertilizers, and heavy metals. Downstream, in this case, the Mississippi River Delta and the Gulf of Mexico, the pollutants cause eutrophication the presence of an excess amount of nutrients (ie., nitrogen and phosphorous). Algal blooms result from this process. Eventually, the blooms die and fall to the sea floor, where they then decompose. During decomposition, oxygen is consumed. In the summer, the oxygen is so depleted tha
