The ring-shaped coral islands known as atolls, like this one in the Maldives Islands in the Indian Ocean, may trace their formation to sea levels repeatedly rising and falling over hundreds of ...

PHYSICAL OCEANOGRAPHY: The collecting of data -- Composition and properties of sea water -- Ice in the sea -- Movements of sea water -- THE SEA BASINS: The shapes of sea basins -- The evolution of sea ...

This striking astronaut photo shows a unique chain of three atolls lined up side-by-side off the coast of Australia. The oval islands were once part of a colossal coral system that rivaled the Great ...