Atlantic Ocean

Atlantic Ocean
CIA · Public domain · source
Name	Atlantic Ocean
Area km2	106460000
Avg depth m	3646
Max depth m	8486
Volume km3	353700000

Atlantic Ocean The Atlantic Ocean is the second-largest oceanic division on Earth, bordered by the Arctic Ocean, Southern Ocean, North America, South America, Europe, and Africa and connecting to the Pacific Ocean via the Drake Passage and to marginal seas such as the Mediterranean Sea and the Caribbean Sea. It has played central roles in the age of Age of Discovery, the Transatlantic slave trade, the Industrial Revolution, and twentieth-century conflicts including the World War I and World War II. The ocean’s physical structure and ecosystems shape climate patterns that affect nations from the United States and Brazil to the United Kingdom, Spain, Morocco, and South Africa.

Etymology

The name "Atlantic" derives from the Atlas (mythology) of classical Greek language and Homeric epics, reflecting ancient contacts among societies such as the Phoenicia, Carthage, and Ancient Greece during the era of Classical antiquity. Medieval cartographers influenced by Ptolemy and later scholars like Gerardus Mercator propagated the name through works that circulated in the courts of Spain and Portugal during the Reconquista and the early Spanish Empire. Renaissance navigators from Portugal and Castile who participated in the Age of Discovery popularized the term in European maritime charts used by Christopher Columbus and Ferdinand Magellan era explorers.

Geography

The basin extends from the Arctic Ocean to the Southern Ocean and spans temperate, tropical, subtropical, and polar regions affecting coastlines of Canada, United States, Mexico, Cuba, Haiti, Dominican Republic, Venezuela, Colombia, Peru, Chile, United Kingdom, Ireland, France, Portugal, Spain, Iceland, Norway, Sweden, Morocco, Algeria, Tunisia, Libya, Egypt, Senegal, Ghana, Nigeria, Cameroon, Gabon, Angola, Namibia, South Africa, Namibia, Argentina, and Uruguay. Prominent marginal seas include the Baltic Sea, North Sea, Gulf of Mexico, Labrador Sea, Sargasso Sea, and Lusitanian Basin areas mapped by agencies like the United States Geological Survey and the British Geological Survey.

Boundaries and Margins

The ocean is bounded by continental shelves and abrupt margins such as the Mid-Atlantic Ridge dividing western and eastern sectors, the steep slopes off the Scotia Sea near the South Sandwich Islands, and the passive margins along Brazilian Highlands and the West African Craton. Political maritime limits are governed by instruments like the United Nations Convention on the Law of the Sea and delimitation cases adjudicated at the International Court of Justice and the International Tribunal for the Law of the Sea, influencing claims by states such as United Kingdom in the Falkland Islands and France in overseas departments.

Geology and Origin

Formation of the basin is a consequence of plate tectonics driven by the breakup of Pangaea during the Mesozoic with seafloor spreading along the Mid-Atlantic Ridge and hotspot activity linked to features like the Iceland plume and the Azores hotspot. Continental rifting that separated the Laurentia and Gondwana fragments produced transform faults and fracture zones named in studies by institutions like the Geological Society of America and the American Geophysical Union. Magnetic anomaly patterns first interpreted after work by scientists at the Woods Hole Oceanographic Institution and Scripps Institution of Oceanography underpin the chronology of ocean opening through the Cretaceous and Paleogene.

Bathymetry and Major Features

Major bathymetric features include the Mid-Atlantic Ridge, abyssal plains such as the Hatteras Abyssal Plain, trenches like the Puerto Rico Trench containing the ocean’s deepest point outside subduction zones, fracture zones including the Romanche Fracture Zone, and seamounts of the Azores and Bermuda chains. Submarine canyon systems cut continental shelves off New England and West Africa, while large sedimentary provinces such as the Amazon Fan and Niger Fan host hydrocarbon-bearing strata explored by firms headquartered in Houston and London.

Oceanography and Circulation

Circulation is dominated by the Atlantic Meridional Overturning Circulation (often abbreviated AMOC), which interlinks western boundary currents like the Gulf Stream with eastern gyres and the North Atlantic Drift, transferring heat between the Caribbean Sea, temperate Europe, and polar regions. Wind-driven systems such as the North Atlantic Oscillation modulate surface currents and interact with the El Niño–Southern Oscillation teleconnections studied by National Oceanic and Atmospheric Administration and European Centre for Medium-Range Weather Forecasts researchers. Deep-water formation in the Labrador Sea and Greenland Sea feeds abyssal flows cataloged by programs like Argo and the Global Ocean Observing System.

Climate and Weather Influence

The ocean moderates climate through heat transport that warms climates of Western Europe relative to similar latitudes in Canada and the United States; links to the North Atlantic Oscillation influence winter storms and precipitation patterns studied by the Intergovernmental Panel on Climate Change and national meteorological services like Met Éireann and the National Weather Service (United States). Tropical cyclone genesis in the Saffir–Simpson scale realm affects nations across the Caribbean, Gulf of Mexico, and West Africa, interacting with Saharan dust transport and sea surface temperature anomalies monitored by the National Hurricane Center and European Space Agency.

Marine Biodiversity and Ecosystems

Biological communities range from productive upwelling zones off the Canary Islands and Cape Verde to oligotrophic gyres like the Sargasso Sea supporting unique assemblages such as Sargassum rafts and species studied by the Smithsonian Institution and the Natural History Museum, London. Continental shelf ecosystems support kelp forests along Norway and Iceland, coral reefs in the Bahamas and Belize Barrier Reef Reserve System, and deep-sea communities on hydrothermal vents near the Mid-Atlantic Ridge examined by expeditions from the Monterey Bay Aquarium Research Institute and Rosenstiel School of Marine and Atmospheric Science.

Fisheries and Marine Resources

The ocean sustains major fisheries for species like Atlantic cod, haddock, herring, mackerel, sardine, and tuna, with historic collapses such as the Collapse of the Atlantic northwest cod fishery prompting management reforms by the North Atlantic Fisheries Organization and national agencies like Fisheries and Oceans Canada. Offshore oil and gas basins in the Gulf of Mexico, North Sea, and offshore Brazil are exploited by companies such as Shell plc, BP, and Petrobras, while mineral prospects for cobalt crusts and manganese nodules are the focus of research funded by the International Seabed Authority.

Ocean Chemistry and Biogeochemical Cycles

The ocean’s carbon uptake and buffering capacity influence global carbon budgets considered in Kyoto Protocol and Paris Agreement negotiations, with processes including the biological pump, carbonate compensation, and ocean alkalinity modulated by inputs from river systems such as the Amazon River and Congo River. Nutrient dynamics drive productivity in upwelling zones off Morocco and Portugal, while hypoxia zones linked to eutrophication occur in semi-enclosed basins like the Gulf of Mexico and the Baltic Sea, subject to mitigation efforts coordinated by the European Union and the United States Environmental Protection Agency.

Sea Ice and Polar Interfaces

At high latitudes, interactions with Arctic sea ice and seasonal ice cover in the Greenland Sea influence albedo and freshwater fluxes that affect thermohaline circulation studied by polar programs at the British Antarctic Survey and the Norwegian Polar Institute. Antarctic interfaces in the Weddell Sea and Scotia Sea link to southern circumpolar processes involving the Southern Ocean and research platforms like RRS James Clark Ross and RV Polarstern.

Human History and Exploration

Human engagement includes prehistoric coastal migrations, Norse voyages to Vinland led by figures like Leif Erikson, the era of Age of Discovery with voyages by Christopher Columbus and Vasco da Gama that connected Europe, Africa, and the Americas, and subsequent colonial empires such as the Spanish Empire and Portuguese Empire. Transoceanic trade, the Transatlantic slave trade, and naval conflicts including the Battle of the Atlantic shaped geopolitics involving navies from the Royal Navy, United States Navy, and others, while scientific voyages by HMS Challenger and research cruises by NOAA vessels expanded knowledge of oceanography.

Major shipping routes traverse choke points like the Strait of Gibraltar, the English Channel, and the Panama Canal connecting the ocean to the Pacific Ocean; ports of significance include New York City, Rotterdam, Shanghai (via transshipment), Lisbon, Cape Town, Rio de Janeiro, and Hamburg. Navigation relies on technologies and organizations such as the International Maritime Organization, satellite systems like Global Positioning System, and traffic monitoring by Automatic Identification System networks managed by port authorities and institutions including the Port of Rotterdam Authority.

Economic Importance and Trade

The ocean underpins transatlantic trade in commodities transported by carriers registered in flags such as Panama and Liberia, energy routes for liquefied natural gas and crude oil between producers like Venezuela and consumers in United States and Europe, and offshore investments attracting multinational corporations headquartered in London, New York City, and São Paulo. Financial centers including the New York Stock Exchange and London Stock Exchange list companies that exploit marine resources, while multinational agreements such as the North Atlantic Free Trade Agreement-era arrangements (and successor trade frameworks) affect goods flows.

Environmental Issues and Pollution

Pollution includes chronic oil spills such as the Deepwater Horizon oil spill in the Gulf of Mexico, plastic accumulation zones like the North Atlantic Garbage Patch within subtropical gyres, chemical contaminants traced to industrial centers including Pittsburgh and Manchester, and nutrient runoff from agricultural catchments in the Mississippi River and Ebro River driving coastal eutrophication. Climate-driven issues such as ocean warming and acidification influence coral bleaching in regions like the Caribbean and shifting species distributions documented by agencies like the Intergovernmental Panel on Climate Change.

Conservation and Management

Conservation initiatives include marine protected areas such as the Papahānaumokuākea Marine National Monument model applied in Atlantic regions, multinational governance through bodies like the Convention on Biological Diversity, regional fisheries management organizations including the International Commission for the Conservation of Atlantic Tunas, and NGO advocacy by groups such as World Wide Fund for Nature and Greenpeace. Scientific guidance from organizations like the IUCN underpins designation of Ramsar Convention wetland sites and other measures to protect habitats like mangroves in Florida and seagrass meadows in the Mediterranean Sea.

Political and Legal Status

Maritime jurisdiction follows the United Nations Convention on the Law of the Sea framework for territorial seas, exclusive economic zones, and continental shelf claims adjudicated in disputes involving states such as Spain and United Kingdom over enclaves and France and Brazil over offshore boundaries. Security concerns include cooperation through alliances like NATO, maritime interdiction operations against piracy in Atlantic approaches, and sanctions regimes affecting transit of goods enforced by actors like the United Nations Security Council.

Coastal Populations and Cities

Coastal population centers along the ocean include metropolises such as New York City, Miami, Boston, Lisbon, Barcelona, Marseille, Bordeaux, Dakar, Accra, Lagos, Abidjan, Cape Town, Durban, Rio de Janeiro, Buenos Aires, and Montevideo, all of which face challenges of sea-level rise and storm surge managed by municipal authorities and urban planners with inputs from institutions like the World Bank and United Nations Human Settlements Programme.

Islands and Archipelagos

Notable island groups include the Azores, Madeira, Canary Islands, Bermuda, Bahamas, Greater Antilles (including Cuba and Hispaniola), the Lesser Antilles, the Cape Verde archipelago, the Faroe Islands, and the Svalbard archipelago, many of which are territories of states such as Portugal, Spain, United Kingdom, and Denmark and are important for biodiversity, tourism, and strategic positioning.

Natural Hazards and Extreme Events

The basin is subject to hazards including tropical cyclones affecting the Caribbean and Gulf of Mexico, tsunamis generated by submarine earthquakes near the Azores–Gibraltar Transform Fault, storm surges impacting New Orleans and Galveston, Texas, and harmful algal blooms in semi-enclosed seas like the Baltic Sea and the Gulf of Mexico, with disaster responses coordinated by agencies such as the Federal Emergency Management Agency and regional civil protection services.

Scientific Research and Observation

Research is conducted by universities and institutes like Woods Hole Oceanographic Institution, Scripps Institution of Oceanography, Lamont–Doherty Earth Observatory, National Oceanography Centre (United Kingdom), and national programs such as NOAA and CNRS programs; observational networks include Argo floats, satellite missions by NASA and European Space Agency, and international projects like the Global Ocean Observing System and the Ocean Observatories Initiative, informing assessments by the Intergovernmental Panel on Climate Change and global policy fora.

Category:Oceans