Atlantic Ocean

The Atlantic Ocean is the second largest of the world's five oceanic divisions. It covers about 85 million square kilometers. It makes up around 17% of Earth's surface and about 24% of its water area. This big body of water separates the New World of the Americas, including North America and South America, from the Old World of Afro-Eurasia. Afro-Eurasia includes Africa, Asia, and Europe.

Because of its place between these big lands, the Atlantic Ocean has been very important in history. During the Age of Discovery, trips across the Atlantic made new links between continents. The expedition of Christopher Columbus in 1492 was very important. It started an age of exploration and later the colonization of the Americas by European powers such as Portugal, Spain, France, and the United Kingdom.

The Atlantic Ocean’s weather changes in different places. The South Atlantic stays warm all year because it touches tropical lands. The North Atlantic has milder temperatures with clear seasons. As part of the connected World Ocean, the Atlantic connects to the Arctic Ocean to the north, the Pacific Ocean to the southwest, the Indian Ocean to the southeast, and the Southern Ocean to the south. Some ideas say it reaches all the way to Antarctica. The ocean is split into northern and southern parts by the Equator.

Names

The name "Atlantic" comes from very old times. Around 450 BC, a writer named Herodotus called it the "Sea of Atlas." This was because of the sea near the Strait of Gibraltar and the Atlas Mountains. People in ancient Greece thought the Atlantic was part of a big sea called the Oceanus. They thought this sea surrounded all the land.

During the Age of Discovery, the Atlantic was sometimes called the Great Western Ocean by English mapmakers. Today, some people, especially in Britain and America, call the northern Atlantic "the pond." This is a friendly way to talk about the ocean that connects their countries.

Extent and data

The International Hydrographic Organization has set the borders of the Atlantic Ocean. Some countries may have different ideas about these borders. The Atlantic is next to North America and South America on the west. On the east, it touches Europe and Africa. It links to the Arctic Ocean through places like the Labrador Sea, Denmark Strait, and Norwegian Sea.

In the southeast, the Atlantic meets the Indian Ocean. It also has many bays, gulfs, and seas along its coasts, such as the Caribbean Sea, Gulf of Mexico, and Mediterranean Sea. With these smaller seas, the Atlantic covers a big part of Earth’s surface.

Bathymetry

The bathymetry of the Atlantic Ocean is shaped by a huge underwater mountain range called the Mid-Atlantic Ridge. This ridge stretches from near the North Pole to close to Bouvet Island. It divides the ocean into two parts. The ridge rises over two kilometers above the ocean floor. It creates valleys and volcanoes, including those in Iceland.

The ocean floor has wide areas called continental shelves near Newfoundland, southern South America, and north-eastern Europe. Deep trenches, like the Puerto Rico Trench, mark places where the floor drops very deep. The deepest part of the Atlantic is more than eight thousand meters below the surface.

Water characteristics

Surface water in the Atlantic Ocean can be very cold or very warm, depending on where you are and the time of year. Temperatures can range from below −2 °C (28 °F) to over 30 °C (86 °F). Warmer water is found north of the equator, while colder water is in polar regions.

From October to June, the surface of the Labrador Sea, Denmark Strait, and Baltic Sea is often covered with sea ice. The Coriolis effect makes water in the North Atlantic move in a circle, while water in the South Atlantic moves in the opposite direction. The Atlantic also has tides, with two high tides every day. In areas north of 40° North, there is a special pattern of wind and water called the North Atlantic oscillation.

The Atlantic is the saltiest of the world's major oceans. Surface water salinity ranges from 33 to 37 parts per thousand (3.3–3.7%) by weight. Salinity changes because of evaporation, rain, rivers, and sea ice melting. The lowest salinity is near the equator because of lots of rain, while the highest salinity is around 25° north and south, where there is little rain and lots of evaporation.

The Atlantic Ocean has four main types of surface water, each with different temperature and salinity. These waters mix and flow, affecting the ocean's features. The North Atlantic deep water forms in the northern parts and helps move warm water north, influencing the world's climate. Currents like the warm-water North Atlantic Gyre and South Atlantic Gyre help move heat around the planet.

The Gulf Stream is a big current that flows northeast from North America, bringing warm water to the North Atlantic. This warm water helps keep Europe's temperatures milder. The North Atlantic Subpolar Gyre, north of the North Atlantic Gyre, is important for climate changes and is affected by currents and local features.

The Sargasso Sea, in the western North Atlantic, is surrounded by the Gulf Stream, North Atlantic Drift, and North Equatorial Current. It is famous for its floating seaweed, Sargassum, which gives a home to many sea creatures, including the sargassum fish. The Sargasso Sea is where both European eels and American eels lay their eggs. They travel thousands of kilometers to reach their adult homes in North America, Europe, and northern Africa.

Climate

The climate of the Atlantic Ocean is shaped by the temperatures of its surface waters, water currents, and winds. Because the ocean can store and release a lot of heat, areas near it have milder climates with smaller changes between seasons compared to areas far inland. The ocean provides much of the moisture in the air through evaporation, and its currents move warm and cold water to different parts of the world, affecting nearby lands.

The Gulf Stream and the North Atlantic Drift help keep temperatures milder in places like southeastern North America and northwestern Europe. Cold currents can create fog near eastern Canada and northwestern Africa. Every winter, the Icelandic Low brings storms, and icebergs can be found near the Grand Banks of Newfoundland. Hurricanes sometimes occur in the western North Atlantic during summer and autumn.

Geology and plate tectonics

The Atlantic Ocean sits on dense rock made of materials like basalt and gabbro. Near the edges, where it meets the land, the ocean floor is covered with fine clay, silt, and other small particles. The oldest parts of the ocean floor in the Atlantic are far from the shorelines, near Africa and North America.

The Atlantic Ocean formed when the huge ancient landmass called Pangaea broke apart. This happened mainly in the middle of the ocean, between what is now North America and Africa. As the continents moved apart, new ocean floor formed in between them.

Future of the Atlantic

Scientists are studying how the Atlantic Ocean might change in the very far future. One idea is that a new system could form near the Gibraltar Arc. This might cause the Atlantic Ocean to close up one day.

Another idea is that the Atlantic might keep getting wider while the Pacific Ocean closes first. If this happens, the continents might come together to form a new supercontinent called Amasia in about 200 to 300 million years.

History

Main category: History of the Atlantic Ocean

The Atlantic Ocean has a long history, shaped by people and discoveries over many years. Early humans moved from Africa to Europe, Asia, and Australia, leaving signs along Atlantic coasts. They settled and used the ocean's resources, creating large piles of shells called shell middens. These show how people lived long ago.

Later, during a cold time called the Last Glacial Maximum, ice covered much of North America. People lived in places like Beringia, connecting Siberia to Alaska. When the ice melted, people moved south. The Norse Vikings were among the first Europeans to reach places like the Faroe Islands, Iceland, and Greenland, though these settlements had many difficulties.

The Atlantic Ocean was very important during the Age of Discovery. Explorers like Christopher Columbus reached the Americas in 1492, and Vasco da Gama found a sea route to India around Africa. These trips led to European colonization of the Americas, bringing big changes to the world, including new trade routes and many people moving across the ocean.

Economy

The Atlantic Ocean is very important for the economies of countries around it. It helps with moving things and talking between continents. The ocean also has many natural resources, like fish and oil, that people use every day.

Fisheries are important along the Atlantic coasts. Places like the Grand Banks of Newfoundland and the waters near Iceland have lots of fish. Over time, some fish numbers have gone down because people caught too many. Scientists and governments work together to help the fish come back. Today, many people rely on these fisheries for food and jobs.

Environmental issues

The Atlantic Ocean has many environmental problems that can hurt animals and nature. Some sea animals like manatees, seals, sea lions, turtles, and whales are in danger. Some fishing methods, such as drift net fishing, can harm dolphins, albatrosses, and other birds, and also reduce the number of fish.

Pollution is also a big problem. Rivers carry chemicals from farms, animal waste, and human waste into the ocean. This can create areas with very little oxygen, called hypoxia, where many sea creatures cannot live. Human trash, called marine debris or marine litter, often ends up in parts of the ocean called gyres and can wash up on beaches. One famous polluted area is the North Atlantic garbage patch.

Climate change affects the Atlantic Ocean too. Warmer ocean temperatures can cause stronger hurricanes. The ocean takes in a lot of heat, which makes the water expand and helps cause sea level rise. Melting ice, like from Greenland, will also raise sea levels over time.