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Atlantic Ocean: the story on HearLore | HearLore
Atlantic Ocean
The Atlantic Ocean is the second largest of the world's five oceanic divisions, yet its true significance lies not in its size but in the human drama it has hosted for five centuries. Covering approximately 17% of Earth's surface and 24% of its water, this vast, S-shaped basin has served as the primary stage for the collision of civilizations, the movement of billions of tons of goods, and the tragic displacement of millions of people. Before the Age of Discovery, the Atlantic was a mythological boundary known to the Greeks as the sea beyond the pillars of Hercules, a place where the known world ended and the great Oceanus began. It was not until the 15th century that this barrier became a bridge, transforming from a terrifying expanse into the central artery of global history. The ocean's role in separating the New World of the Americas from the Old World of Afro-Eurasia created a dynamic that would define the modern era, turning the Atlantic into the center of globalization, colonization, and the histories of nations that still shape our world today.
The Mid-Atlantic Ridge and the Birth of Continents
Beneath the waves, the Atlantic Ocean is being born and dying in a slow, geological dance that has been unfolding for hundreds of millions of years. The bathymetry of the ocean is dominated by the Mid-Atlantic Ridge, a submarine mountain range that runs from south of the North Pole to the subantarctic Bouvet Island, effectively dividing the Atlantic longitudinally into two halves. This ridge is not merely a geological feature but a divergent boundary where the North American and Eurasian plates separate in the north, and the South American and African plates separate in the south. The ridge rises more than 2,000 meters above the surrounding ocean floor, and its rift valley is the site of constant volcanic activity, producing basaltic volcanoes like Eyjafjallajökull in Iceland and pillow lava on the deep ocean floor. The discovery of this ridge in the 1870s by the Challenger expedition and its subsequent mapping by the German Meteor expedition in the 1920s led to the general acceptance of seafloor spreading and plate tectonics, revolutionizing our understanding of Earth's history. The oldest oceanic crust in the Atlantic is up to 145 million years old, situated off the west coast of Africa and the east coast of North America, marking the beginning of the breakup of the supercontinent Pangaea.
The Currents That Shaped Civilizations
The Atlantic Ocean is not a static body of water but a dynamic system of currents that has dictated the climate of continents and the fate of explorers. The Gulf Stream, flowing north-east from the North American coast at Cape Hatteras, and its northern extension, the North Atlantic Drift, transport warm water into the North Atlantic, preventing the British Isles and northwestern Europe from experiencing the severe winters that other locations at the same high latitude endure. Without this system, temperatures in the North Atlantic and Europe would plunge dramatically, altering the course of human history. The Coriolis effect circulates North Atlantic water in a clockwise direction, while South Atlantic water circulates counter-clockwise, creating distinct gyres that trap marine life and debris. The Sargasso Sea, an area defined by the floating of two species of Sargassum seaweed, serves as the spawning ground for European and American eels, which migrate thousands of kilometers to reach their foraging areas. These currents also transport moisture and air over land areas, influencing precipitation and climate patterns across the globe, making the Atlantic a critical component of the Earth's thermohaline circulation.
What percentage of Earth's surface does the Atlantic Ocean cover?
The Atlantic Ocean covers approximately 17% of Earth's surface and 24% of its water. This vast, S-shaped basin serves as the primary stage for the collision of civilizations and the movement of billions of tons of goods.
When was the Mid-Atlantic Ridge discovered and by which expedition?
The Mid-Atlantic Ridge was discovered in the 1870s by the Challenger expedition. Subsequent mapping by the German Meteor expedition in the 1920s led to the general acceptance of seafloor spreading and plate tectonics.
How many enslaved Africans were shipped into the New World during the Atlantic slave trade?
An estimated 9.5 million enslaved Africans were shipped into the New World between the 15th century and 1888. Brazil became the last part of the Americas to end the trade in 1888.
What is the age of the oldest oceanic crust in the Atlantic Ocean?
The oldest oceanic crust in the Atlantic is up to 145 million years old. This crust is situated off the west coast of Africa and the east coast of North America.
When did the Atlantic northwest cod fishery collapse?
The Atlantic northwest cod fishery collapsed in the early 1990s. This collapse followed the introduction of European and Asian distant-water fleets from the 1950s to the 1970s.
How much did the Atlantic meridional overturning circulation slow down between 1957 and 2004?
A 2005 report indicated that the Atlantic meridional overturning circulation slowed down by 30% between 1957 and 2004. Research in 2024 highlighted a significant weakening of the AMOC by approximately 12% over the past two decades.
The Atlantic Ocean became the center of human history when Christopher Columbus reached the Americas in 1492, sailing under the Spanish flag. Six years later, Vasco da Gama reached India under the Portuguese flag, proving that the Atlantic and Indian Oceans are connected, and in 1500, Pedro Álvares Cabral reached Brazil, taken by the currents of the South Atlantic Gyre. These explorations led to the rapid conquest and colonization of large territories in the New World by Spain and Portugal, who forced the Amerindian population into slavery to exploit the vast quantities of silver and gold they found. The Atlantic slave trade, which became the norm and an integral part of the colonization, saw an estimated 9.5 million enslaved Africans shipped into the New World between the 15th century and 1888, when Brazil became the last part of the Americas to end the trade. The trade was officially abolished in the British Empire and the United States in 1808, and slavery itself was abolished in the British Empire in 1838 and in the United States in 1865 after the Civil War. From Columbus to the Industrial Revolution, trans-Atlantic trade, including colonialism and slavery, became crucial for Western Europe, leading to sustained growth and urbanization in countries with direct access to the Atlantic.
The Silent War of the Deep
The Atlantic Ocean has been the site of some of the most significant naval battles and conflicts in human history, from the Age of Discovery to the Cold War. During the 16th to 19th centuries, the Atlantic was the center of both an eponymous slave trade and the Columbian exchange, while occasionally hosting naval battles that shaped the balance of power between European nations. The ocean remained a core component of trade around the world, and after World War II, major military operations became rarer, though notable postwar conflicts include the Cuban Missile Crisis and the Falklands War. The ocean's strategic importance was highlighted during the 20th century, when naval battles and growing trade from regional American powers like the United States and Brazil both increased in degree. The Atlantic has also been the site of environmental disasters, such as the USAF C-124 aircraft from Dover Air Force Base, Delaware, which was carrying three nuclear bombs over the Atlantic Ocean when it experienced a loss of power, resulting in the jettisoning of two nuclear bombs that were never recovered.
The Fish That Fed the World
The shelves of the Atlantic Ocean host one of the world's richest fishing resources, with the most productive areas including the Grand Banks of Newfoundland, the Scotian Shelf, Georges Bank off Cape Cod, and the waters around Iceland. In 1497, John Cabot became the first Western European since the Vikings to explore mainland North America, and one of his major discoveries was the abundant resources of Atlantic cod off Newfoundland, referred to as "Newfoundland Currency," which yielded some 200 million tons of fish over five centuries. However, from the 1950s to the 1970s, the introduction of European and Asian distant-water fleets in the area dramatically increased the fishing capacity and the number of exploited species, leading to the collapse of the Atlantic northwest cod fishery in the early 1990s. The population of a number of deep-sea fishes also collapsed in the process, including American plaice, redfish, and Greenland halibut, together with flounder and grenadier. Fisheries have undergone significant changes since the 1950s, and global catches can now be divided into three groups, with the Atlantic experiencing overall decline following historical peaks.
The Ocean's Hidden Dangers
The Atlantic Ocean is not only a source of life but also a repository of human-made waste and environmental threats. Marine pollution, a generic term for the entry into the ocean of potentially hazardous chemicals or particles, is caused by rivers carrying agriculture fertilizer chemicals, livestock and human waste, leading to hypoxia and the creation of dead zones. Marine debris, which is also known as marine litter, describes human-created waste floating in a body of water, with the North Atlantic garbage patch estimated to be hundreds of kilometers across in size. The ocean's climate is changing, with North Atlantic hurricane activity increasing over past decades because of increased sea surface temperature, changes that can be attributed to either the natural Atlantic Multidecadal Oscillation or to anthropogenic climate change. A 2005 report indicated that the Atlantic meridional overturning circulation slowed down by 30% between 1957 and 2004, and in 2024, research highlighted a significant weakening of the AMOC by approximately 12% over the past two decades, threatening the global climate system.