A report on Ocean

World map of the five-ocean model with approximate boundaries
The Atlantic, one component of the system, makes up 23% of the "global ocean".
Surface view of the Atlantic Ocean
World distribution of mid-oceanic ridges; USGS
Map of large underwater features (1995, NOAA)
Ocean chlorophyll concentration is a proxy for phytoplankton biomass. In this map, blue colors represent lower chlorophyll and reds represent higher chlorophyll. Satellite-measured chlorophyll is estimated based on ocean color by how green the color of the water appears from space.
The major oceanic zones, based on depth and biophysical conditions
Ocean surface currents
A map of the global thermohaline circulation; blue represents deep-water currents, whereas red represents surface currents.
Map of the Gulf Stream, a major ocean current that transports heat from the equator to northern latitudes and moderates the climate of Europe.
High tide and low tide in the Bay of Fundy, Canada.
The ocean is a major driver of Earth's water cycle.
Annual mean sea surface salinity in practical salinity units (psu) from the World Ocean Atlas.
Sea surface oxygen concentration in moles per cubic meter from the World Ocean Atlas.
Diagram of the ocean carbon cycle showing the relative size of stocks (storage) and fluxes.
Residence time of elements in the ocean depends on supply by processes like rock weathering and rivers vs. removal by processes like evaporation and sedimentation.

Body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water.

- Ocean
World map of the five-ocean model with approximate boundaries

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Coastal sea waves at Paracas National Reserve, Ica, Peru


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Coastal sea waves at Paracas National Reserve, Ica, Peru
Animated map exhibiting the world's oceanic waters. A continuous body of water encircling Earth, the World Ocean is divided into a number of principal areas with relatively uninhibited interchange among them. Five oceanic divisions are usually defined: Pacific, Atlantic, Indian, Arctic, and Southern; the last two listed are sometimes consolidated into the first three.
Marginal seas as defined by the International Maritime Organization
Composite images of the Earth created by NASA in 2001
Salinity map taken from the Aquarius Spacecraft. The rainbow colours represent salinity levels: red = 40 ‰, purple = 30 ‰
When the wave enters shallow water, it slows down and its amplitude (height) increases.
The 2004 tsunami in Thailand
Surface currents: red–warm, blue–cold
The global conveyor belt shown in blue with warmer surface currents in red
High tides (blue) at the nearest and furthest points of the Earth from the Moon
Three types of plate boundary
Praia da Marinha in Algarve, Portugal
The Baltic Sea in the archipelago of Turku, Finland
Coral reefs are among the most biodiverse habitats in the world.
A thornback cowfish
Map showing the seaborne migration and expansion of the Austronesians beginning at around 3000 BC
Gerardus Mercator's 1569 world map. The coastline of the old world is quite accurately depicted, unlike that of the Americas. Regions in high latitudes (Arctic, Antarctic) are greatly enlarged on this projection.
Naval warfare: The explosion of the Spanish flagship during the Battle of Gibraltar, 25 April 1607 by Cornelis Claesz van Wieringen, formerly attributed to Hendrik Cornelisz Vroom
Shipping routes, showing relative density of commercial shipping around the world
German factory ship, 92 m long
Fishing boat in Sri Lanka
Scuba diver with face mask, fins and underwater breathing apparatus
Tidal power: the 1 km Rance Tidal Power Station in Brittany generates 0.5 GW.
Minerals precipitated near a hydrothermal vent
Reverse osmosis desalination plant
Great wave off the coast of Kanagawa by Katsushika Hokusai, c. 1830
Dutch Golden Age painting: The Y at Amsterdam, seen from the Mosselsteiger (mussel pier) by Ludolf Bakhuizen, 1673
The Oceanids (The Naiads of the Sea), a painting by Gustave Doré (c. 1860)

The sea, connected as the world ocean or simply the ocean, is the body of salty water that covers approximately 71 percent of the Earth's surface.

Extent of the Atlantic Ocean according to the 2002 IHO definition, excluding Arctic and Antarctic regions

Atlantic Ocean

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Extent of the Atlantic Ocean according to the 2002 IHO definition, excluding Arctic and Antarctic regions
The Aethiopian Ocean in a 1710 French map of Africa
False color map of ocean depth in the Atlantic basin
As the Gulf Stream meanders across the North Atlantic from the North American east coast to Western Europe its temperature drops by 20 C-change.
Path of the thermohaline circulation. Purple paths represent deep-water currents, while blue paths represent surface currents.
In the subpolar gyre of the North Atlantic warm subtropical waters are transformed into colder subpolar and polar waters. In the Labrador Sea this water flows back to the subtropical gyre.
Approximate extent of the Sargasso Sea
Sargassum fish (Histrio histrio)
Waves in the trade winds in the Atlantic Ocean—areas of converging winds that move along the same track as the prevailing wind—create instabilities in the atmosphere that may lead to the formation of hurricanes.
Tropical wet and dry climate in San Andrés Island Caribbean, Colombia
Iceberg A22A in the South Atlantic Ocean
Excavation of the Ertebølle middens in 1880
Based on the medieval Íslendingasögur sagas, including the Grœnlendinga saga, this interpretative map of the "Norse World" shows that Norse knowledge of the Americas and the Atlantic remained limited.
The Atlantic Gyres influenced the Portuguese discoveries and trading port routes, here shown in the India Run ("Carreira da Índia"), which would be developed in subsequent years.
Embarked and disembarked slaves in the Atlantic slave trade 1525–1863 (first and last slave voyages)
Cod fishery in Norway
Banks of the North-East Atlantic
Banks of the North-West Atlantic
Capture of Atlantic north-west cod in million tons
Bahama Banks
Agulhas Bank
Marine debris strewn over the beaches of the South Atlantic Inaccessible Island

The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about 106460000 km2.

Pacific Ocean

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Largest and deepest of Earth's five oceanic divisions.

Largest and deepest of Earth's five oceanic divisions.

Partial picture of the Pacific Ocean from space, by the Apollo 11 crew
Model of a Fijian drua, an example of an Austronesian vessel with a double-canoe (catamaran) hull and a crab claw sail
Map showing the migration of the Austronesian peoples, the first seaborne human migration in history (c.3000-1500 BCE)
Map showing a large number of Spanish expeditions across the Pacific Ocean from the 16th to 18th centuries including the Manila galleon route between Acapulco and Manila, the first transpacific trade route in history.
Universalis Cosmographia, the Waldseemüller map dated 1507, from a time when the nature of the Americas was ambiguous, particularly North America, as a possible part of Asia, was the first map to show the Americas separating two distinct oceans. South America was generally considered a "new world" and shows the name "America" for the first time, after Amerigo Vespucci
The bathyscaphe Trieste, before her record dive to the bottom of the Mariana Trench, 23 January 1960
Abel Aubert du Petit-Thouars taking over Tahiti on 9 September 1842
Sunset over the Pacific Ocean as seen from the International Space Station. tops of thunderclouds are also visible.
The island geography of the Pacific Ocean Basin
Regions, island nations and territories of Oceania
Tarawa Atoll in the Republic of Kiribati
Sunset in Monterey County, California, U.S.
Impact of El Niño and La Niña on North America
Typhoon Tip at global peak intensity on 12 October 1979
Ring of Fire. The Pacific is ringed by many volcanoes and oceanic trenches.
Ulawun stratovolcano situated on the island of New Britain, Papua New Guinea
Mount Saint Helens in 2020
Pacific Ocean currents have created 3 "islands" of debris.
Marine debris on a Hawaiian coast
Prime Minister Suga declined to drink the bottle of Fukushima's treated radioactive water that he was holding, which would otherwise be discharged to the Pacific. 2020.
Made in 1529, the Diogo Ribeiro map was the first to show the Pacific at about its proper size
Map of the Pacific Ocean during European Exploration, circa 1754.
Maris Pacifici by Ortelius (1589). One of the first printed maps to show the Pacific Ocean<ref>{{cite web|url=https://www.loc.gov/item/prn-01-093/|title=Library Acquires Copy of 1507 Waldseemüller World Map – News Releases (Library of Congress)|publisher=Loc.gov|access-date=April 20, 2013}}</ref>
Map of the Pacific Ocean during European Exploration, circa 1702–1707
Ladrilleros Beach in Colombia on the coast of Chocó natural region
Tahuna maru islet, French Polynesia
Los Molinos on the coast of Southern Chile

At 165250000 km2 in area (as defined with a southern Antarctic border), this largest division of the World Ocean—and, in turn, the hydrosphere—covers about 46% of Earth's water surface and about 32% of its total surface area, larger than Earth's entire land area combined 148,000,000 sqkm.

The Antarctic Ocean, as delineated by the draft 4th edition of the International Hydrographic Organization's Limits of Oceans and Seas (2002)

Southern Ocean

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The Antarctic Ocean, as delineated by the draft 4th edition of the International Hydrographic Organization's Limits of Oceans and Seas (2002)
A general delineation of the Antarctic Convergence, sometimes used by scientists as the demarcation of the Southern Ocean
The International Hydrographic Organization's delineation of the "Southern Ocean" has moved steadily southwards since the original 1928 edition of its Limits of Oceans and Seas.
"Southern Ocean" as alternative to the Aethiopian Ocean, 18th century
1928 delineation
1937 delineation
Area inside the black line indicates the area constituting the Pacific Ocean prior to 2002; darker blue areas are its informal current borders following the recreation of the Southern Ocean and the reinclusion of marginal seas
Continents and islands of the Southern Ocean
A map of Australia's official interpretation of the names and limits of oceans and seas around Australia
1564 Typus Orbis Terrarum, a map by Abraham Ortelius showed the imagined link between the proposed continent of Antarctica and South America.
Portrait of Edmund Halley by Godfrey Kneller (before 1721)
"Terres Australes" (sic) label without any charted landmass
James Weddell's second expedition in 1823, depicting the brig and the cutter Beaufroy
Famous official portrait of Captain James Cook who proved that waters encompassed the southern latitudes of the globe. "He holds his own chart of the Southern Ocean on the table and his right hand points to the east coast of Australia on it."
Admiral von Bellingshausen
USS Vincennes at Disappointment Bay, Antarctica in early 1840.
1911 South Polar Regions exploration map
Frank Hurley, As time wore on it became more and more evident that the ship was doomed ( trapped in pack ice), National Library of Australia.
MS Explorer in Antarctica in January 1999. She sank on 23 November 2007 after hitting an iceberg.
Seas that are parts of the Southern Ocean
Manganese nodule
An iceberg being pushed out of a shipping lane by (L to R) USS Burton Island (AGB-1), USS Atka (AGB-3), and USS Glacier (AGB-4) near McMurdo Station, Antarctica, 1965
The Antarctic Circumpolar Current (ACC) is the strongest current system in the world oceans, linking the Atlantic, Indian and Pacific basins.
Location of the Southern Ocean gyres.
Regional Working Group zones for SOOS
Orca (Orcinus orca) hunting a Weddell seal in the Southern Ocean
A wandering albatross (Diomedea exulans) on South Georgia
Fish of the Notothenioidei suborder, such as this young icefish, are mostly restricted to the Antarctic and Subantarctic
Weddell seals (Leptonychotes weddellii) are the most southerly of Antarctic mammals.
Antarctic krill (Euphausia superba) are a keystone species of the food web.
A female warty squid (Moroteuthis ingens)
An adult and sub-adult Minke whale are dragged aboard the Japanese whaling vessel
Severe cracks in an ice pier in use for four seasons at McMurdo Station slowed cargo operations in 1983 and proved a safety hazard.

The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica.

The Arctic Ocean, with borders as delineated by the International Hydrographic Organization (IHO), including Hudson Bay (some of which is south of 57°N latitude, off the map).

Arctic Ocean

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The Arctic Ocean, with borders as delineated by the International Hydrographic Organization (IHO), including Hudson Bay (some of which is south of 57°N latitude, off the map).
Decrease of old Arctic Sea ice 1982–2007
Thule archaeological site
Emanuel Bowen's 1780s map of the Arctic features a "Northern Ocean".
The Arctic region showing the Northeast Passage, the Northern Sea Route within it, and the Northwest Passage.
A bathymetric/topographic map of the Arctic Ocean and the surrounding lands.
The Arctic region; of note, the region's southerly border on this map is depicted by a red isotherm, with all territory to the north having an average temperature of less than 10 C in July.
Distribution of the major water mass in the Arctic Ocean. The section sketches the different water masses along a vertical section from Bering Strait over the geographic North Pole to Fram Strait. As the stratification is stable, deeper water masses are denser than the layers above.
Density structure of the upper 1200 m in the Arctic Ocean. Profiles of temperature and salinity for the Amundsen Basin, the Canadian Basin and the Greenland Sea are sketched.
A copepod
The Kennedy Channel.
Sea cover in the Arctic Ocean, showing the median, 2005 and 2007 coverage
Three polar bears approach USS Honolulu near the North Pole.
Minke whale
Walruses on Arctic ice floe

The Arctic Ocean is the smallest and shallowest of the world's five major oceans.

Extent of the Indian Ocean according to International Hydrographic Organization

Indian Ocean

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Extent of the Indian Ocean according to International Hydrographic Organization
The Indian Ocean, according to the CIA The World Factbook (blue area), and as defined by the IHO (black outline - excluding marginal waterbodies).
During summer, warm continental masses draw moist air from the Indian Ocean hence producing heavy rainfall. The process is reversed during winter, resulting in dry conditions.
Air pollution in South Asia spread over the Bay of Bengal and beyond.
Madagascar's Elephant bird, Mauritius's Dodo bird and ostrich (from left to right)
According to the Coastal hypothesis, modern humans spread from Africa along the northern rim of the Indian Ocean.
The Austronesian maritime trade network was the first trade routes in the Indian Ocean.
Greco-Roman trade with ancient India according to the Periplus Maris Erythraei 1st century CE
The economically important Silk Road was blocked from Europe by the Ottoman Empire in c. undefined 1453 with the fall of the Byzantine Empire. This spurred exploration, and a new sea route around Africa was found, triggering the Age of Discovery.
For most of the 16th century, the Portuguese dominated the Indian Ocean trade.
Malé's population has increased from 20,000 people in 1987 to more than 220,000 people in 2020.
An unnamed Chagossian on Diego Garcia in 1971 shortly before the British expelled the islanders when the island became a U.S. military base. The man spoke a French-based creole language and his ancestors were most likely brought to the uninhabited island as slaves in the 19th century.
Major ocean trade routes in the world includes the northern Indian Ocean.
Mombasa Port on Kenya's Indian Ocean coast

The Indian Ocean is the third-largest of the world's five oceanic divisions, covering 70560000 km2 or ~19.8% of the water on Earth's surface.

Seawater off San Andrés


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Seawater off San Andrés
Temperature-salinity diagram of changes in density of water
Ocean salinity at different latitudes in the Atlantic and Pacific
Annual mean sea surface salinity expressed in the Practical Salinity Scale for the World Ocean. Data from the World Ocean Atlas
Diagram showing concentrations of various salt ions in seawater. The composition of the total salt component is: 55%, 30.6%,  7.7%,  3.7%,  1.2%,  1.1%,
Other 0.7%. Note that the diagram is only correct when in units of wt/wt, not wt/vol or vol/vol.

Seawater, or salt water, is water from a sea or ocean.

Estimated change in seawater pH caused by human-created carbon dioxide between the 1700s and the 1990s, from the Global Ocean Data Analysis Project (GLODAP) and the World Ocean Atlas

Ocean acidification

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Estimated change in seawater pH caused by human-created carbon dioxide between the 1700s and the 1990s, from the Global Ocean Data Analysis Project (GLODAP) and the World Ocean Atlas
Here is a detailed image of the full carbon cycle
NOAA provides evidence for the upwelling of "acidified" water onto the Continental Shelf. In the figure above, note the vertical sections of (A) temperature, (B) aragonite saturation, (C) pH, (D) DIC, and (E) p on transect line 5 off Pt. St. George, California. The potential density surfaces are superimposed on the temperature section. The 26.2 potential density surface delineates the location of the first instance in which the undersaturated water is upwelled from depths of 150 to 200 m onto the shelf and outcropping at the surface near the coast. The red dots represent sample locations.
Ocean Acidification Infographic
The cycle between the atmosphere and the ocean
Distribution of (A) aragonite and (B) calcite saturation depth in the global oceans
This map shows changes in the aragonite saturation level of ocean surface waters between the 1880s and the most recent decade (2006–2015). Aragonite is a form of calcium carbonate that many marine animals use to build their skeletons and shells. The lower the saturation level, the more difficult it is for organisms to build and maintain their skeletons and shells. A negative change represents a decrease in saturation.
Here is detailed diagram of the carbon cycle within the ocean
Bjerrum plot: Change in carbonate system of seawater from ocean acidification.
Shells of pteropods dissolve in increasingly acidic conditions caused by increased amounts of atmospheric
A normally-protective shell made thin, fragile and transparent by acidification
Drivers of hypoxia and ocean acidification intensification in upwelling shelf systems. Equatorward winds drive the upwelling of low dissolved oxygen (DO), high nutrient, and high dissolved inorganic carbon (DIC) water from above the oxygen minimum zone. Cross-shelf gradients in productivity and bottom water residence times drive the strength of DO (DIC) decrease (increase) as water transits across a productive continental shelf.
Demonstrator calling for action against ocean acidification at the People's Climate March (2017).
Ocean acidification: mean seawater pH. Mean seawater pH is shown based on in-situ measurements of pH from the Aloha station.
"Present day" (1990s) sea surface pH
Present day alkalinity
"Present day" (1990s) sea surface anthropogenic {{chem|CO|2}}
Vertical inventory of "present day" (1990s) anthropogenic {{chem|CO|2}}
Change in surface {{chem|CO|3|2-}} ion from the 1700s to the 1990s
Present day DIC
Pre-Industrial DIC
A NOAA (AOML) in situ {{chem|CO|2}} concentration sensor (SAMI-CO2), attached to a Coral Reef Early Warning System station, utilized in conducting ocean acidification studies near coral reef areas
A NOAA (PMEL) moored autonomous {{chem|CO|2}} buoy used for measuring {{chem|CO|2}} concentration and ocean acidification studies

Ocean acidification is the ongoing decrease in the pH value of the Earth's oceans, caused by the uptake of carbon dioxide from the atmosphere.

Map of the Mediterranean Sea

Mediterranean Sea

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Sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the east by the Levant.

Sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the east by the Levant.

Map of the Mediterranean Sea
Greek (red) and Phoenician (yellow) colonies in antiquity c. the 6th century BC
The Roman Empire at its farthest extent in AD 117
The Battle of Lepanto, 1571, ended in victory for the European Holy League against the Ottoman Turks.
The bombardment of Algiers by the Anglo-Dutch fleet in support of an ultimatum to release European slaves, August 1816
Borders of the Mediterranean Sea
Approximate extent of the Mediterranean drainage basin (dark green). Nile basin only partially shown
Map of the Mediterranean Sea from open Natural Earth data, 2020
Alexandria, the largest city on the Mediterranean
Barcelona, the second largest metropolitan area on the Mediterranean Sea (after Alexandria) and the headquarters of the Union for the Mediterranean
The Acropolis of Athens with the Mediterranean Sea in the background
The ancient port of Jaffa (now in Tel Aviv-Yafo), from which the biblical Jonah set sail before being swallowed by a whale
Catania, Sicily, Italy, with Mount Etna in the background
İzmir, the third metropolis of Turkey (after Istanbul and Ankara)
Africa (left, on horizon) and Europe (right), as seen from Gibraltar
Positano, Italy, Tyrrhenian Sea
View of the Saint George Bay, and snow-capped Mount Sannine from a tower in the Beirut Central District
The Port of Marseille seen from L'Estaque
Sarandë, Albania, stands on an open-sea gulf of the Ionian sea in the central Mediterranean.
The two biggest islands of the Mediterranean: Sicily and Sardinia (Italy)
Predominant surface currents for June
A submarine karst spring, called vrulja, near Omiš; observed through several ripplings of an otherwise calm sea surface.
Messinian salinity crisis before the Zanclean flood
The thermonuclear bomb that fell into the sea recovered off Palomares, Almería, 1966
Stromboli volcano in Italy
The reticulate whipray is one of the species that colonised the Eastern Mediterranean through the Suez Canal as part of the ongoing Lessepsian migration.
A cargo ship cruises towards the Strait of Messina
Port of Trieste
Kemer Beach in Antalya on the Turkish Riviera (Turquoise Coast). In 2019, Turkey ranked sixth in the world in terms of the number of international tourist arrivals, with 51.2 million foreign tourists visiting the country.
Coast of Alexandria, view From Bibliotheca Alexandrina, Egypt
Beach of Hammamet, Tunisia
The beach of la Courtade in the Îles d'Hyères, France
Sardinia's south coast, Italy
Pretty Bay, Malta
Panoramic view of Piran, Slovenia
Panoramic view of Cavtat, Croatia
View of Neum, Bosnia and Herzegovina
A view of Sveti Stefan, Montenegro
Ksamil Islands, Albania
Navagio, Greece
Ölüdeniz, Turquoise Coast, Turkey
Paphos, Cyprus
Burj Islam Beach, Latakia, Syria
A view of Raouché off the coast of Beirut, Lebanon
A view of Haifa, Israel
Old city of Ibiza Town, Spain
Les Aiguades near Béjaïa, Algeria
El Jebha, a port town in Morocco
Europa Point, Gibraltar
Panoramic view of La Condamine, Monaco
Sunset at the Deir al-Balah beach, Gaza Strip

The Mediterranean Sea covers an area of about 2500000 km2, representing 0.7% of the global ocean surface, but its connection to the Atlantic via the Strait of Gibraltar—the narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates the Iberian Peninsula in Europe from Morocco in Africa—is only 14 km wide.

Continental shelf

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Portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea.

Portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea.

Though the continental shelf is treated as a physiographic province of the ocean, it is not part of the deep ocean basin proper, but the flooded margins of the continent.