A report on Southern Ocean

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.

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

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Western Australia

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State occupying the western percent of the land area of Australia excluding external territories.

State occupying the western percent of the land area of Australia excluding external territories.

Map first drawn in 1618 by Hessel Gerritsz showing the charted coast of Australia. Chartings after 1618, for example by François Thijssen in 1627, were added to the engraved plate between 1628 and 1632.
Melchisédech Thévenot's Hollandia Nova—Terre Australe in his travel anthology (Relations de divers voyages curieux) published in 1664, and which seems to be a copy of Archipelagus Orientalis sive Asiaticus by Joan Blaeu in the Atlas of the Great Elector (Atlas des Großen Kurfürsten) from 1659. The latitude staff depicted by Thévenot falls along the Zaragoza antimeridian from the Treaty of Zaragoza of 1529 between Castile and Portugal, and which complemented the Tordesillas meridian from the Treaty of Tordesillas of 1494.
John Forrest was the first Premier of Western Australia.
Western Australian cities, towns, settlements and road network.
Köppen climate types in Western Australia
A quokka on Rottnest Island
The black swan is the state bird of Western Australia
Ngaanyatjarra children, from the desert regions of Western Australia
Western Australia's capital and largest city, Perth. Its metropolitan area is home to 75% of the state's population.
WA population growth 1829–2010
Distribution of the Western Australian population (as density of SA1 census districts)
Brockman 4, an iron ore mine in the Pilbara
Western Australia's resource commodity mix, 2007
Major commodity mix, 2008–2009
Camel rides are a popular tourist activity at Cable Beach in Broome
Parliament House
A 1933 meeting of the Dominion League in support of secession.
University of Western Australia
Seven West Media's Newspaper House, where The West Australian newspaper is produced
ABC studios in East Perth
WA Museum Boola Bardip
Art Gallery of Western Australia
Matches between the two Western Australian teams, the West Coast Eagles and the Fremantle Dockers, are known as the Western Derby
"West Australia" on a 1902 stamp

It is bounded by the Indian Ocean to the north and west, and the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east.

Monument commemorating the first flight across the Bass Strait, by Arthur Leonard Long in 1919. Note the spelling "".

Bass Strait

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Strait separating the island state of Tasmania from the Australian mainland .

Strait separating the island state of Tasmania from the Australian mainland .

Monument commemorating the first flight across the Bass Strait, by Arthur Leonard Long in 1919. Note the spelling "".
The shoreline of Tasmania and Victoria about 14,000 years ago as sea levels were rising, showing some of the human archaeological sites – see Prehistory of Australia
Shortest distance between the coasts of Bass Strait: South West Point on Wilsons Promontory to the northern tip of the Stanley peninsula
Map of Bass Strait including major island groups
Major infrastructure connections between Tasmania and Victoria.
Amphitrite on 1936 stamp commemorating completion of cable

The Australian Hydrographic Service does not consider it to be part of its expanded definition of the Southern Ocean, but rather states that it lies with the Tasman Sea.

World map of the five-ocean model with approximate boundaries

Ocean

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

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

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.
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Separate names are used to identify five different areas of the ocean: Pacific (the largest), Atlantic, Indian, Southern (Antarctic), and Arctic (the smallest).

The Antarctic region and its boundary, the Antarctic Convergence

Subantarctic

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Region in the Southern Hemisphere, located immediately north of the Antarctic region.

Region in the Southern Hemisphere, located immediately north of the Antarctic region.

The Antarctic region and its boundary, the Antarctic Convergence
Diagram of the major ocean currents, showing the Antarctic Circumpolar Current (ACC). In addition to the global thermohaline circulation, the ACC strongly influences regional and global climate.
Global thermohaline circulation strongly influences regional and global climate. Blue paths represent deep-water currents, while red paths represent surface currents.
Diagram showing different water masses in the Southern Ocean.
Antarctica and surrounding islands in relation to the Antarctic Convergence and the 60th parallel south
Trees growing along the north shore of the Beagle Channel, 55°S.
Satellite image of the southern tip of Heard Island. Cape Arkona is seen on the left side of the image, with Lied Glacier just above and Gotley Glacier just below. Big Ben Volcano and Mawson Peak are seen at the lower right side of the image.
Satellite image of central South Georgia: Harker Glacier, Cumberland Bay, Thatcher Peninsula, Allardyce Range, Mount Paget.
Neumayer Glacier, Cumberland West Bay, South Georgia, circa 1882–1883.
Neumayer Glacier, Cumberland West Bay, South Georgia, circa 1882–1883.
Nordenskjold Glacier, Cumberland Bay, South Georgia.
Air-sea exchange of CO2
Retreat of San Rafael Glacier from 1990 to 2000. San Quintín Glacier is shown in the background

The ACC is the most important ocean current in the Southern Ocean, and the only current that flows completely around the Earth.

Coastline of the Great Australian Bight

Great Australian Bight

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Large oceanic bight, or open bay, off the central and western portions of the southern coastline of mainland Australia.

Large oceanic bight, or open bay, off the central and western portions of the southern coastline of mainland Australia.

Coastline of the Great Australian Bight
The Great Australian Bight south of the Nullarbor. Credit Jacques Descloitres, Visible Earth, NASA.
Great Australian Bight Marine Park, 2007
Great Australian Bight 2015
Cliff overlooking Commonwealth Marine Reserve

The AHS considers it to be part of the Southern Ocean, using the expanded Australian definition used for this ocean.

Tabular iceberg in the Scotia Sea, 1996

Scotia Sea

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Tabular iceberg in the Scotia Sea, 1996
Approximate area of the sea in the Southern Hemisphere
Map of Scotia Sea. Toponyms: Undersea relief, maritime, nearby lands, countries and cities. Isobath interval: 2000 m

The Scotia Sea is a sea located at the northern edge of the Southern Ocean at its boundary with the South Atlantic Ocean.

Weddell seal

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Relatively large and abundant true seal with a circumpolar distribution surrounding Antarctica.

Relatively large and abundant true seal with a circumpolar distribution surrounding Antarctica.

A Weddell seal at a breathing hole
Baby Weddell seal, Adélie Land
Weddell seal pup with its grey natal coat, Deception Island
At the Neko Harbour, Antarctica

The Weddell seal was discovered and named in the 1820s during expeditions led by British sealing captain James Weddell to the area of the Southern Ocean now known as the Weddell Sea.

Location of the Cosmonauts Sea, proposed as a sea of the Southern Ocean

Cosmonauts Sea

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Location of the Cosmonauts Sea, proposed as a sea of the Southern Ocean

The Cosmonauts Sea (Море Космонавтов, More Kosmonavtov; sometimes misspelled Cosmonaut Sea) was a proposed sea name as part of the Southern Ocean, off the Prince Olav Coast and Enderby Land, Antarctica, between about 30°E and 50°E.

Orca

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Toothed whale belonging to the oceanic dolphin family, of which it is the largest member.

Toothed whale belonging to the oceanic dolphin family, of which it is the largest member.

Variations in Antarctic orcas
Different angle views of a typical killer whale's appearance (female)
Differences of dorsal fins between males (front) and females (background)
Orca attacking a strap-toothed beaked whale
Orca beaching to capture sea lion at Valdes Peninsula
Orcas swimming in close synchronization to create a wave to wash the seal off the ice floe
Orcas, like this one near Alaska, commonly breach, often lifting their entire bodies out of the water.
A pair of orcas in the Pacific Northwest
An orca plays with a ball of ice, soon after a researcher threw a snowball at the whale.
Mother orca with calf near South Georgia
The "type C" orca has two-toned grey colouring, including a dark "dorsal cape", in body areas where most orcas have solid black colouring. Research is ongoing into whether one or more orca types are distinct species in need of protection.
An adult female and her calf
Haida sculpture by Bill Reid
Male orca depicted in St Mary's in Greifswald, Germany, 1545
In 2002, the orphan Springer was successfully returned to her family.
The orca named Old Tom swims alongside a whaleboat, flanking a whale calf. The boat is being towed by a harpooned whale (not visible here), near Eden, Australia.
Lolita, at the Miami Seaquarium, is one of the oldest whales in captivity.

A cosmopolitan species, orcas can be found in all of the world's oceans in a variety of marine environments, from Arctic and Antarctic regions to tropical seas.

Krill

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Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans.

Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans.

Krill anatomy explained, using Euphausia superba as a model
The gills of krill are externally visible
Phytoplankton convert CO2, which has dissolved from the atmosphere into the surface oceans (90 Gt yr−1) into particulate organic carbon (POC) during primary production (~ 50 Gt C yr−1). Phytoplankton are then consumed by krill and small zooplankton grazers, which in turn are preyed upon by higher trophic levels. Any unconsumed phytoplankton form aggregates, and along with zooplankton faecal pellets, sink rapidly and are exported out of the mixed layer (< 12 Gt C yr−1 14). Krill, zooplankton and microbes intercept phytoplankton in the surface ocean and sinking detrital particles at depth, consuming and respiring this POC to CO2 (dissolved inorganic carbon, DIC), such that only a small proportion of surface-produced carbon sinks to the deep ocean (i.e., depths > 1000 m). As krill and smaller zooplankton feed, they also physically fragment particles into small, slower- or non-sinking pieces (via sloppy feeding, coprorhexy if fragmenting faeces), retarding POC export. This releases dissolved organic carbon (DOC) either directly from cells or indirectly via bacterial solubilisation (yellow circle around DOC). Bacteria can then remineralise the DOC to DIC (CO2, microbial gardening). Diel vertically migrating krill, smaller zooplankton and fish can actively transport carbon to depth by consuming POC in the surface layer at night, and metabolising it at their daytime, mesopelagic residence depths. Depending on species life history, active transport may occur on a seasonal basis as well. Numbers given are carbon fluxes (Gt C yr−1) in white boxes and carbon masses (Gt C) in dark boxes.
A nauplius of Euphausia pacifica hatching, emerging backwards from the egg
The head of a female krill of the sac-spawning species Nematoscelis difficilis with her brood sac. The eggs have a diameter of 0.3 –
A krill swarm
Beating pleopods of a swimming Antarctic krill
Krill (as swarms and individuals) feed on phytoplankton at the surface (1) leaving only a proportion to sink as phytodetrital aggregates (2), which are broken up easily and may not sink below the permanent thermocline. Krill also release faecal pellets (3) whilst they feed, which can sink to the deep sea but can be consumed (coprophagy) and degraded as they descend (4) by krill, bacteria and zooplankton. In the marginal ice zone, faecal pellet flux can reach greater depths (5). Krill also release moults, which sink and contribute to the carbon flux (6). Nutrients are released by krill during sloppy feeding, excretion and egestion, such as iron and ammonium (7, see Fig. 2 for other nutrients released), and if they are released near the surface can stimulate phytoplankton production and further atmospheric CO2 drawdown. Some adult krill permanently reside deeper in the water column, consuming organic material at depth (8). Any carbon (as organic matter or as CO2) that sinks below the permanent thermocline is removed from subjection to seasonal mixing and will remain stored in the deep ocean for at least a year (9). The swimming motions of migrating adult krill that migrate can mix nutrient-rich water from the deep (10), further stimulating primary production. Other adult krill forage on the seafloor, releasing respired CO2 at depth and may be consumed by demersal predators (11). Larval krill, which in the Southern Ocean reside under the sea ice, undergo extensive diurnal vertical migration (12), potentially transferring CO2 below the permanent thermocline. Krill are consumed by many predators including baleen whales (13), leading to storage of some of the krill carbon as biomass for decades before the whale dies, sinks to the seafloor and is consumed by deep sea organisms.
When krill moult they release dissolved calcium, fluoride and phosphorus from the exoskeleton (1). The chitin (organic material) that forms the exoskeleton contributes to organic particle flux sinking to the deep ocean. Krill respire a portion of the energy derived from consuming phytoplankton or other animals as carbon dioxide (2), when swimming from mid/deep waters to the surface in large swarms krill mix water, which potentially brings nutrients to nutrient-poor surface waters (3), ammonium and phosphate is released from the gills and when excreting, along with dissolved organic carbon, nitrogen (e.g., urea) and phosphorus (DOC, DON and DOP, 2 & 4). Krill release fast-sinking faecal pellets containing particulate organic carbon, nitrogen and phosphorus (POC, PON and POP) and iron, the latter of which is bioavailable when leached into surrounding waters along with DOC, DON and DOP (5).
Deep frozen plates of Antarctic krill for use as animal feed and raw material for cooking
Dried fermented krill, used to make Bagoong alamang, a type of shrimp paste from the Philippines

In the Southern Ocean, one species, the Antarctic krill, Euphausia superba, makes up an estimated biomass of around 379,000,000 tonnes, making it among the species with the largest total biomass.