What is the Dead Zone
- The Dead Zone is an area of water where the oxygen levels in the water are too low to support marine life, commonly known as hypoxia. This has now become an annual event and is beginning to be a serious issue in the gulf.
- The Dead Zone is located in the northern part of the Gulf of Mexico, where the Mississippi River runs into the Gulf. It stretches on westward beyond the border of Texas.
What causes hypoxia?
Hypoxia is caused by pollution in the form of excess nutrients,
mainly phosphates and nitrates, that flow into the Gulf of Mexico from the Mississippi River which feeds the
algae population and it eventually becomes overwhelming.
- The algae eventually dies out and falls to the ocean floor where it then begins decomposing, depleting the oxygen from the ocean floor, and forcing the marine life to flee the area or die out.
When does this usually occur
- Hypoxia tends to reappear in the spring and summer months, usually May through September, because the river tends to carry more nutrients, because there is more run-off.
- Hypoxia tends to diminish during the fall and winter because hurricanes and tropical storms break the algae up and oxygen begins to appear in the water again.
- In 1993 the dead zone grew to double its size because of the big flood of the Mississippi River. In 1998, there was a severe drought, therefore, there was little runoff, and the Dead Zone was nearly absent.