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A closer look at Gulf ‘Dead Zone’

NOAA’s offices in Mississippi have formed a partnership to provide data about dissolved oxygen from the seasonal hypoxic area, or “Dead Zone,” in the Gulf of Mexico.

Hypoxia occurs when the amount of dissolved oxygen in the water becomes too low to support most marine life, including shrimp, crabs and fish. Mostly a summertime phenomenon, this low dissolved oxygen, or “dead zone” begins to form in June and extends from the mouth of the Mississippi River westward to Texas. Though hypoxia in the Gulf of Mexico has appeared naturally for thousands of years, its geographic area has increased significantly since NOAA began measuring it in the early 1980s.

NOAA scientists believe this increase, attributed in part to the growing use of nitrogen fertilizers in the Mississippi River watershed, has led to a demand for more information about the causes and effects of hypoxia.