In this respect they are totally different from the original hard-rock volcanic islands that first formed Bermuda. This change is a result of the activities of marine organisms that colonized the original volcanic rock. This group of oceanic islands has always been far from any continental landmass. It arose about one hundred and ten million years ago due to volcanic activity along the Atlantic mid-oceanic ridge. It is the northern most coral reef system in the world and owes its subtropical climate to its position in the Sargasso Sea, east of the warm Gulf Stream current.
All ocean basins have massive surface currents moving in virtually constant clockwise patterns.
The current of greatest importance to Bermuda is the Gulf Stream. This current originates in the Atlantic in tropical seas just north of the equator. The tropical climate heats the water and the N.E. trade winds push the water to the west through the Caribbean, north along Central America, and around the Gulf of Mexico. The current is intensified by passage through the narrow Straits of Florida, between the USA and Cuba, where it becomes the Gulf Stream. This fast, warm current passes just to the west of Bermuda, and eddies from the Gulf Stream surround the island.