THE ATLANTIC OCEAN

With a total area of about 106,400,000 square kilometers (41,100,000 sq mi), it covers approximately 20 percent of the Earth's surface and about 29 percent of its water surface area.

The oldest known mention of "Atlantic" is in The Histories of Herodotus around 450 BC: Atlantis thalassa. The term Ethiopic Ocean, derived from Ethiopia, was applied to the southern Atlantic as late as the mid- 19th century. Before Europeans discovered other oceans, their term "ocean" was synonymous with the waters beyond the Strait of Gibraltar that are now known as the Atlantic. The early Greeks believed this ocean to be a gigantic river encircling the world.

The principal feature of the bathymetry (bottom topography) is a submarine mountain range called the Mid-Atlantic Ridge. It extends from Iceland in the north to approximately 58° South latitude, reaching a maximum width of about 860 nautical miles (1,590 km; 990 mi).

Puerto Rico Trench, in the North Atlantic, is the deepest trench at 8,605 metres

On average, the Atlantic is the saltiest major ocean; Surface water salinity in the open ocean ranges from 33 to 37 parts per thousand (3.3 – 3.7%) by mass and varies with latitude and season

Water temperatures, which vary with latitude, current systems, and season and reflect the latitudinal distribution of solar energy, range from below 2 to over 30 °C.

From October to June the surface is usually covered with sea ice in the Labrador Sea, Denmark Strait, and Baltic Sea.