Every summer a dead zone of oxygen-depleted water the size of Massachusetts forms in the Gulf of Mexico; others have been found off Oregon and in the Chesapeake Bay, Lake Erie and the Baltic and Black seas. Some studies indicate that North Pole seawater could turn caustic in 10 years, and that the Southern Ocean already may be saturated with carbon dioxide.

A recent bird kill off the coast of Washington state came without warning, said Jane Lubchenco, the administrator of the National Oceanic and Atmospheric Administration (NOAA). "There will be more surprises than that," she said.

The danger signals are everywhere, some related to climate change and greenhouse gases and others not:

-- Every eight months, 11 million gallons of oil run off the nation's roads and driveways into waters that eventually reach the sea, the Pew Oceans Commission said in 2003. That's the equivalent of an Exxon Valdez-size oil spill.