This measure was signed into law as P.L. 105-383, wherein Title VI authorizes appropriations through NOAA to conduct research, monitoring, education, and management activities for the prevention, reduction, and control of hypoxia. As the scientific community has become more concerned about possible impacts of hypoxia, congressional interest in monitoring and addressing the problem has grown. This report presents an overview of the causes of hypoxia, the U.S. areas of most concern, relevant federal research programs, and legislation in the 105th Congress to authorize and fund additional research. Contents Introduction and Background Hypoxic Areas Gulf of Mexico Dead Zone Impacts of the Gulf of Mexico Dead Zone on Fishing Policy and Management Efforts References Introduction and Background Hypoxia refers to a depressed concentration of dissolved oxygen in water. In extremely low oxygen environments, less tolerant marine animals cannot survive and either leave the area or die.
Mortality is especially likely for sedentary species.
In addition, spawning areas and other essential habitat can be destroyed by the lack of oxygen. The recovery of marine ecosystems following an hypoxic event has not been extensively studied. Eutrophication occurs naturally when offshore winds or surface currents cause cold, nutrient-rich, deep marine waters to rise near coasts, resulting in algal blooms and natural hypoxic events. Many of the hypoxic events along the Pacific and Atlantic coasts are caused by this natural upwelling. Nutrient-rich fresh water is less dense than saltwater and typically flows across the top of the sea water.