The Atlantic Ocean
The Atlantic is the second-biggest ocean on Earth. It sits between Europe and Africa on one side, and the Americas on the other. It is named after Atlas from Greek mythology. The Atlantic has played a bigger role in human history than any other ocean: it was the first ocean to be regularly crossed by ship, and the first to be flown across by plane.
- Surface area85.1 million km²Second biggest, after the Pacific
- Average depth3,646 mAbout 3.6 km from surface to bottom
- Deepest pointPuerto Rico Trenchapprox. 8,376 m, off Puerto Rico
- Lengthapprox. 16,000 km north-southFrom the Arctic to Antarctica
- Famous currentThe Gulf StreamKeeps Britain mild for its latitude
- First crossedColumbus, 1492Modern era. Vikings had done it 500 years earlier
How big is the Atlantic compared to the others?
Surface area in millions of km².
The Atlantic is the second biggest ocean. It is growing wider by a few centimetres every year as the Mid-Atlantic Ridge slowly pushes the Americas and Europe further apart.
What is the Atlantic Ocean?
The Atlantic is a long S-shaped ocean running from the Arctic in the north to the Southern Ocean around Antarctica. It is split into two parts at the Equator: the North Atlantic and the South Atlantic. The Atlantic touches over 50 countries and borders almost all of the major civilisations of human history.
The Mid-Atlantic Ridge
Running right down the middle of the Atlantic from the Arctic to the Southern Ocean is a giant chain of underwater mountains called the Mid-Atlantic Ridge. It is the longest mountain range on Earth, approx. 16,000 km long. The ridge marks the boundary between two tectonic plates that are slowly moving apart. New seafloor is created here as hot magma rises up to fill the gap, which is why the Atlantic gets a few centimetres wider every year.
The Mid-Atlantic Ridge breaks the ocean surface in only a few places. The most famous is Iceland, which is actually sitting astride the ridge. That is why Iceland has so many volcanoes and hot springs.
The Gulf Stream
The Atlantic is home to the most famous ocean current of all: the Gulf Stream. It is a warm, fast-flowing river of water that starts in the Gulf of Mexico, flows up the eastern coast of the United States, and then heads across to Europe. By the time it reaches western Europe it has lost some of its heat, but it still keeps places like Britain and Norway much milder than they would otherwise be. London is the same distance from the Equator as Calgary in Canada, but London has much warmer winters thanks to the Gulf Stream.
Atlantic explorers
The Atlantic was the first ocean to be regularly crossed by ship. The Vikings reached the coast of North America around 1000 AD, around 500 years before Christopher Columbus made his voyage from Spain in 1492. Columbus's voyage opened up regular trade and conquest between Europe and the Americas, with all the good and terrible consequences that followed.
The Atlantic was also the first ocean to be flown across by plane. Charles Lindbergh made the first solo non-stop flight from New York to Paris in 1927.
Deeper dive: thermohaline circulation, hurricanes and the Sargasso Sea
The Atlantic plays a critical role in the global thermohaline circulation, sometimes called the "ocean conveyor belt". Warm surface water moves from the tropics northwards via the Gulf Stream and its continuation, the North Atlantic Drift. When it reaches the cold waters around Greenland and Iceland, it cools, becomes denser and sinks to the deep ocean floor. This deep water then flows slowly southwards, through the South Atlantic, around Africa and into the Indian and Pacific Oceans, where it eventually rises back to the surface over thousands of years. The whole cycle keeps the climate of western Europe far milder than it would otherwise be at its latitude. There is concern that melting Greenland ice could weaken this circulation as the cold meltwater dilutes the dense salty water that drives the sinking.
The Atlantic is the birthplace of hurricanes that strike the Caribbean, the US Gulf Coast and the eastern seaboard. Atlantic hurricane season runs from June to November, when ocean surface temperatures are warmest. Storms typically form near the west coast of Africa from disturbances rolling off the Sahara, then strengthen as they cross the warm tropical Atlantic. Devastating examples include Hurricane Katrina (2005, New Orleans), Hurricane Maria (2017, Puerto Rico), and Hurricane Sandy (2012, north-eastern US). Climate change is making the most powerful hurricanes more common.
The Sargasso Sea, in the middle of the North Atlantic, is the only sea in the world with no land boundaries. It is bounded by ocean currents (the Gulf Stream to the west, the North Atlantic Current to the north, the Canary Current to the east, the North Atlantic Equatorial Current to the south) and named after the floating mats of Sargassum seaweed that drift on its surface. The seaweed provides a vital habitat for many species, including eels, sea turtles and the rare slender sargassum fish, which has even evolved camouflage to match the weed.
The biggest ocean is the Pacific. The warmest is the Indian. The icy one at the top of the world is the Arctic Ocean.