Scientists Studying Gulf's 'Dead Zone'

Through mid-July, scientists from NOAA's National Coast Data Development Center and the agency's Fisheries Service at Stennis Space Center will look at data about dissolved oxygen from the ''dead zone'' areas in the Gulf of Mexico.

The scientists believe the zone forms in June and stretches 5,000-square-miles from the mouth of the Mississippi River toward the Texas coast.

The condition, known as hypoxia, occurs when the amount of dissolved oxygen in the water is too low to support most marine life. The scientists say the trend has increased dramatically since studies first began in the early 1980s.

Researchers believe the dead zone is caused by an influx of polluted freshwater from the Mississippi and Atchafalaya rivers. Freshwater floats over salt water and acts as a barrier to oxygen. Meanwhile, pollution flows from the rivers into the Gulf, creating algae plumes that further choke off the oxygen.

''The science community is determined to find the causes and impacts of hypoxia to marine life in the Gulf,'' said Gregory W. Withee, assistant administrator for NOAA Satellite and Information Service, NCDDC's lead agency.

The scientists, aboard the NOAA vessel, Oregon II, will study the Gulf waters from Brownsville, Texas, to the mouth of the Mississippi River. The team will measure seawater temperatures, salinity, chlorophyll and dissolved oxygen levels at more than 200 locations.

During its four-week study, the scientists will continually generate new maps and provide that data on the Internet. The first map will look at the continental shelf from Brownsville to Corpus Christi, Texas and the final maps will look at the Texas-Louisiana coast.