Worry Underwater: Oxygen Levels Drop as Oil Continues to Flow

Marine biologists say the sea animals flee the spill zone the way others would flee a forest fire. With thousands of gallons of oil contaminating their natural habitats, marine creatures press into oil-free waters.

"Their habitat is shrinking, tens of thousands of square miles are affected, and animals moving away from them," said Mobi Salangi, director of the Institute for Marine Mammal Studies. "There are changes in food, the food they eat and their prey."

Plumes of dense oil in shallow waters, up to 50 feet below the surface, have sucked up oxygen. Tests by the Dauphin Island Sea Lab usually show oxygen levels in the shallow waters at nearly eight parts per million. They're now down to two parts per million -- four times lower than normal.