The Antarctic realm is one of eight terrestrial

biogeographic realm A biogeographic realm is the broadest biogeography, biogeographic division of Earth's land surface, based on distributional patterns of terrestrial animal, terrestrial organisms. They are subdivided into bioregions, which are further subdivid ...

s. The ecosystem includes

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

and several island groups in the southern

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

and Indian oceans. The continent of Antarctica is so cold that it has supported only 2 vascular plants for millions of years, and its flora presently consists of around 250

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

s, 100

moss Mosses are small, non-vascular plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Wilhelm Philippe Schimper, Schimp. 1879) may also refer to the parent group bryo ...

es, 25–30

liverworts Liverworts are a group of non-vascular plant, non-vascular embryophyte, land plants forming the division Marchantiophyta (). They may also be referred to as hepatics. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in wh ...

, and around 700 terrestrial and aquatic

alga Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular microalgae, suc ...

l species, which live on the areas of exposed rock and soil around the shore of the continent. Antarctica's two flowering plant species, the Antarctic hair grass (''

Deschampsia antarctica ''Deschampsia antarctica'', the Antarctic hair grass, is one of two flowering plants native to Antarctica, the other being '' Colobanthus quitensis'' (Antarctic pearlwort). Ecology ''Deschampsia antarctica'' mainly occurs on the South Orkney ...

'') and Antarctic pearlwort (''

Colobanthus quitensis ''Colobanthus quitensis'', also known as the Antarctic pearlwort, is one of two native flowering plants found in the Antarctic region, the other being Antarctic hair grass. It has yellow flowers and grows about tall, giving it a moss-like appea ...

''), are found on the northern and western parts of the

Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martin in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctica. ...

. Antarctica is also home to a diversity of animal life, including

penguin Penguins are a group of aquatic flightless birds from the family Spheniscidae () of the order Sphenisciformes (). They live almost exclusively in the Southern Hemisphere. Only one species, the Galápagos penguin, is equatorial, with a sm ...

seals Seals may refer to: * Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly: ** Earless seal, or "true seal" ** Fur seal * Seal (emblem), a device to impress an emblem, used as a means of a ...

, and

whale Whales are a widely distributed and diverse group of fully Aquatic animal, aquatic placental mammal, placental marine mammals. As an informal and Colloquialism, colloquial grouping, they correspond to large members of the infraorder Cetacea ...

s. Several Antarctic and sub-Antarctic island groups are considered part of the Antarctic realm, including

Bouvet Island Bouvet Island ( ; ) is an uninhabited subantarctic volcanic island and dependency of Norway. It is a protected nature reserve, and situated in the South Atlantic Ocean at the southern end of the Mid-Atlantic Ridge, it is the world's most extre ...

, the

Crozet Islands The Crozet Islands (; or, officially, ''Archipel Crozet'') are a sub-Antarctic archipelago of small islands in the southern Indian Ocean. They form one of the five administrative districts of the French Southern and Antarctic Lands. History ...

Heard Island The Territory of Heard Island and McDonald Islands (HIMI) is an Australian external territory comprising a volcanic group of mostly barren Antarctic islands, about two-thirds of the way from Madagascar to Antarctica. The group's overall land ...

, the

Kerguelen Islands The Kerguelen Islands ( or ; in French commonly ' but officially ', ), also known as the Desolation Islands (' in French), are a group of islands in the subantarctic, sub-Antarctic region. They are among the Extremes on Earth#Remoteness, most i ...

, the

McDonald Islands The McDonald Islands () are an uninhabited archipelago in the southern Indian Ocean in the vicinity of Heard Island (). Together with Heard Island, they make up the Australian external territory of Heard Island and McDonald Islands. The ...

, the

Prince Edward Islands The Prince Edward Islands are two small uninhabited subantarctic volcanic islands in the southern Indian Ocean that are administered by South Africa. They are named Marion Island (named after Marc-Joseph Marion du Fresne, 1724–1772) and P ...

, the South Georgia Group, the

South Orkney Islands The South Orkney Islands are a group of List of Antarctic and sub-Antarctic islands, islands in the Southern Ocean, about north-east of the tip of the Antarctic Peninsula South Sandwich Islands The South Sandwich Islands () are a chain of uninhabited volcanic islands in the South Atlantic Ocean. They are administered as part of the British Overseas Territory of South Georgia and the South Sandwich Islands. The chain lies in the sub-A ...

, and the

South Shetland Islands The South Shetland Islands are a group of List of Antarctic and subantarctic islands, Antarctic islands located in the Drake Passage with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the n ...

. These islands have a somewhat milder climate than Antarctica proper, and support a greater diversity of

tundra In physical geography, a tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. There are three regions and associated types of tundra: #Arctic, Arctic, Alpine tundra, Alpine, and #Antarctic ...

plants, although they are all too windy and cold to support trees.

Antarctic krill Antarctic krill (''Euphausia superba'') is a species of krill found in the Antarctica, Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000� ...

is the

keystone species A keystone species is a species that has a disproportionately large effect on its natural environment relative to its abundance. The concept was introduced in 1969 by the zoologist Robert T. Paine. Keystone species play a critical role in main ...

of the ecosystem of the

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the world ocean, generally taken to be south of 60th parallel south, 60° S latitude and encircling Antarctica. With a size of , it is the seco ...

, and is an important food organism for

leopard seal The leopard seal (''Hydrurga leptonyx''), also referred to as the sea leopard, is the second largest species of seal in the Antarctic (after the southern elephant seal). It is a top order predator, feeding on a wide range of prey including cep ...

fur seal Fur seals are any of nine species of pinnipeds belonging to the subfamily Arctocephalinae in the family Otariidae. They are much more closely related to sea lions than Earless seal, true seals, and share with them external ears (Pinna (anatomy ...

crabeater seal The crabeater seal (''Lobodon carcinophaga''), also known as the krill-eater seal, is a true seal with a circumpolar distribution around the coast of Antarctica. They are the only member of the genus ''Lobodon''. They are medium- to large-sized ( ...

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

, icefish,

albatross Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes (the tubenoses). They range widely in the Southern Ocean and the North Paci ...

es and many other

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s. The ocean there is so full of

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater Aquatic ecosystem, ecosystems. The name comes from the Greek language, Greek words (), meaning 'plant', and (), mea ...

because water rises from the depths to the light-flooded surface, bringing

nutrient A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

s from all oceans back to the

photic zone The photic zone (or euphotic zone, epipelagic zone, or sunlight zone) is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological ...

. On August 20, 2014, scientists confirmed the existence of

microorganism A microorganism, or microbe, is an organism of microscopic scale, microscopic size, which may exist in its unicellular organism, single-celled form or as a Colony (biology)#Microbial colonies, colony of cells. The possible existence of unseen ...

s living below the ice of

History

Millions of years ago, Antarctica was warmer and wetter, and supported the

Antarctic flora Antarctic flora are a distinct community of vascular plants which evolved millions of years ago on the supercontinent of Gondwana. In 2025, species of Antarctica flora reside on several now separated areas of the Southern Hemisphere, including ...

, including forests of

podocarps Podocarpaceae is a large family of mainly southern hemisphere conifers, known in English as podocarps, comprising about 156 species of evergreen trees and shrubs.James E. Eckenwalder. 2009. ''Conifers of the World''. Portland, Oregon: Timber Pres ...

and

southern beech ''Nothofagus'', also known as the southern beeches, is a genus of 43 species of trees and shrubs native to the Southern Hemisphere, found across southern South America (Chile, Argentina) and east and southeast Australia, New Zealand, New Guin ...

. Antarctica was also part of the ancient supercontinent of

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

land, which gradually broke up by

continental drift Continental drift is a highly supported scientific theory, originating in the early 20th century, that Earth's continents move or drift relative to each other over geologic time. The theory of continental drift has since been validated and inc ...

starting 110 million years ago. The separation of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

from Antarctica 30–35 million years ago allowed the Antarctic Circumpolar Current to form, which isolated Antarctica climatically and caused it to become much colder. The Antarctic flora subsequently died out in Antarctica, but is still an important component of the flora of southern

Neotropical The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In biogeogra ...

(

Latin America and the Caribbean The term Latin America and the Caribbean (LAC) is an English language, English-language acronym referring to the Latin American and the Caribbean region. The term LAC covers an extensive region, extending from The Bahamas and Mexico to Argentina ...

) and

Australasian realm The Australasian realm is one of eight biogeographic realms that is coincident with, but not (by some definitions) the same as, the geographical region of Australasia. The realm includes Australia, the island of New Guinea (comprising Papua Ne ...

s, which were also former parts of Gondwana. Some botanists recognize an Antarctic Floristic Kingdom that includes Antarctica,

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

, and parts of Temperate South America where the Antarctic Flora is still a major component.

Ecoregions

The Antarctic realm is divided into 17

ecoregion An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...

s:Eric Dinerstein, David Olson et al. (2017). An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm, BioScience, Volume 67, Issue 6, June 2017, Pages 534–545, https://doi.org/10.1093/biosci/bix014

References

Bibliography

* *

Life in the Freezer ''Life in the Freezer'' is a BBC nature documentary series written and presented by David Attenborough, first transmitted in the United Kingdom from 18 November 1993. A study of the seasonal cycle of Antarctica, it was the first of Attenborough ...

, a

BBC The British Broadcasting Corporation (BBC) is a British public service broadcaster headquartered at Broadcasting House in London, England. Originally established in 1922 as the British Broadcasting Company, it evolved into its current sta ...

television Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, ...

series on life on and around Antarctica
Biodiversity at Ardley Island, South Shetland archipelago, Antarctica

– Deep Sea Foraminifera from 4400m depth, Weddell Sea – an image gallery of hundreds of specimens and description
Aliens in Antarctica; Visitors carry unwelcome species into a once pristine environment
May 5, 2012 ''

Science News ''Science News'' (''SN'') is an American monthly magazine devoted to articles about new scientific and technical developments, typically gleaned from recent scientific and technical journals. The periodical has been described as having a scop ...

'' {{Biomes Biogeographic realms Biogeography Phytogeography