Tristan da Cunha is an

archipelago An archipelago ( ), sometimes called an island group or island chain, is a chain, cluster, or collection of islands, or sometimes a sea containing a small number of scattered islands. Examples of archipelagos include: the Indonesian Archi ...

of five islands in the southern

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

, the largest of which is the island of

Tristan da Cunha Tristan da Cunha (), colloquially Tristan, is a remote group of volcanic islands in the South Atlantic Ocean. It is the most remote inhabited archipelago in the world, lying approximately from Cape Town in South Africa, from Saint Helena ...

itself and the second-largest, the remote bird haven,

Gough Island upright=1.3, Map of Gough island Gough Island ( ), also known historically as Gonçalo Álvares, is a rugged volcanic island in the South Atlantic Ocean. It is a dependency of Tristan da Cunha and part of the British overseas territory of Sain ...

. It forms part of a wider territory called

Saint Helena, Ascension and Tristan da Cunha Saint Helena, Ascension and Tristan da Cunha is a British Overseas Territory located in the South Atlantic and consisting of the island of Saint Helena, Ascension Island and the archipelago of Tristan da Cunha including Gough Island. Its name wa ...

which includes

Saint Helena Saint Helena () is a British overseas territory located in the South Atlantic Ocean. It is a remote volcanic tropical island west of the coast of south-western Africa, and east of Rio de Janeiro in South America. It is one of three constitu ...

and

Ascension Island Ascension Island is an isolated volcanic island, 7°56′ south of the Equator in the South Atlantic Ocean. It is about from the coast of Africa and from the coast of South America. It is governed as part of the British Overseas Territory o ...

Location and description

This archipelago, 1500 miles (2500 km) from the continents of Africa and South America, is one of the most remote inhabited places on earth. It consists of the following islands: * the main island Tristan da Cunha and its surrounding islands **

, the main island and largest () area: **

Inaccessible Island Inaccessible Island is a volcanic island located in the South Atlantic Ocean, south-west of Tristan da Cunha. Its highest point, Cairn Peak, reaches , and the island is in area. The volcano was last active six million years ago and is curren ...

area: **

Nightingale Islands The Nightingale Islands are a group of three islands in the South Atlantic Ocean, part of the Tristan da Cunha territory. They consist of Nightingale Island, Middle Island and Stoltenhoff Island. The islands are administered by the United King ...

area: ***

Nightingale Island Nightingale Island is an active volcanic island in the South Atlantic Ocean, in area, part of the Tristan da Cunha group of islands. They are administered by the United Kingdom as part of the British overseas territory, overseas territory of Sai ...

area: *** Middle Island area: ***

Stoltenhoff Island Stoltenhoff Island is a small uninhabited island in the South Atlantic Ocean, part of the Nightingale Islands. It is the smallest of the Nightingale Islands, and is to the north west of Nightingale Island itself. They are governed as part of Tr ...

area: *

(''Diego Alvarez'') area: important as the largest undisturbed cool-temperate island habitat in the South Atlantic Ocean. The main island is quite mountainous; the only flat area is the location of the capital,

Edinburgh of the Seven Seas Edinburgh of the Seven Seas is the main settlement of the island of Tristan da Cunha, in Saint Helena, Ascension and Tristan da Cunha, an overseas territory of the United Kingdom, in the South Atlantic Ocean. Locally, it is referred to as The Se ...

, on the northwest coast, and of the agricultural area named

Potato Patches Potato Patches, also known as Patches Plain or, colloquially, ''The Patches'', is an agricultural area and uninhabited rural settlement in Tristan da Cunha, in Saint Helena, Ascension and Tristan da Cunha, an overseas territory of the United Kingd ...

. The highest point is a volcano called

Queen Mary's Peak Queen Mary's Peak is the summit of the island of Tristan da Cunha, in the South Atlantic Ocean. It has an elevation of 2,062 metres (6,765 ft) above sea level. It is named after Mary of Teck, the Queen consort of King George V. It is the hi ...

reaching ; it is covered by

snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout ...

in winter and is listed as an

ultra prominent peak An ultra-prominent peak, or Ultra for short, is a mountain summit with a topographic prominence of or more; it is also called a P1500. The prominence of a peak is the minimum height of climb to the summit on any route from a higher peak, or fro ...

. Tristan da Cunha is thought to have been formed by a long-lived centre of upwelling

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

called the

Tristan hotspot The Tristan hotspot is a volcanic hotspot which is responsible for the volcanic activity which forms the volcanoes in the southern Atlantic Ocean. It is thought to have formed the island of Tristan da Cunha and the Walvis Ridge on the African Plat ...

. The climate is marine cool-temperate with small temperature differences between summer and winter () and between day and night. Sandy Point on the east coast is reputed to be the warmest and driest place on the island, being in the lee of the

prevailing wind In meteorology, prevailing wind in a region of the Earth's surface is a surface wind that blows predominantly from a particular direction. The dominant winds are the trends in direction of wind with the highest speed over a particular point on ...

Flora

Even the smaller islands have some plant cover, with the larger ones dominated by

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...

s and

moss Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta (''sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and hor ...

. Flora on the archiplego includes many

endemic species Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

and many that have a broad circumpolar distribution in the South Atlantic and South Pacific Oceans. Thus many of the species that occur in Tristan da Cunha occur as far away as

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. For example, the species '' Nertera depressa'' was first collected in Tristan da Cunha, but has since been recorded in occurrence as far distant as New Zealand.

Fauna

Tristan da Cunha is home to ocean-going species including

subantarctic fur seal The subantarctic fur seal (''Arctocephalus tropicalis'') is found in the southern parts of the Indian, Pacific, and Atlantic Oceans. It was first described by Gray in 1872 from a specimen recovered in northern Australia—hence the inappropri ...

, the

southern elephant seal The southern elephant seal (''Mirounga leonina'') is one of two species of elephant seals. It is the largest member of the clade Pinnipedia and the order Carnivora, as well as the largest extant marine mammal that is not a cetacean. It gets it ...

and birds such as

northern rockhopper penguin The northern rockhopper penguin, Moseley's rockhopper penguin, or Moseley's penguin (''Eudyptes moseleyi'') is a penguin species native to the southern Indian and Atlantic Oceans. It is described as distinct from the southern rockhopper penguin. ...

s and

macaroni penguin The macaroni penguin (''Eudyptes chrysolophus'') is a species of penguin found from the Subantarctic to the Antarctic Peninsula. One of six species of crested penguin, it is very closely related to the royal penguin, and some authorities conside ...

s. The islands are important for their bird life both those established on the islands and breeding seabirds, of which twenty species nest on Gough Island alone. Important species include

Tristan albatross The Tristan albatross (''Diomedea dabbenena'') is a large seabird from the albatross family. One of the great albatrosses of the genus ''Diomedea'', it was only widely recognised as a full species in 1998. Taxonomy Albatrosses belong to the fami ...

Tristan thrush The Tristan thrush (''Turdus eremita''), also known as the starchy,Hince (2000). is a species of bird in the thrush family that is endemic to the British overseas territories of the isolated Tristan da Cunha archipelago in the South Atlantic Oc ...

, Tristan bunting,

Gough bunting The Gough finch (''Rowettia goughensis'') or Gough bunting, is a critically endangered species of songbird. Taxonomy The Gough finch was formally described in 1904 by the British ornithologist William Eagle Clarke from a specimen collected on ...

Gough moorhen The Gough moorhen (''Gallinula comeri'') is a medium-sized, almost flightless bird that is similar to the common moorhen (''Gallinula chloropus''), but is smaller, stockier, and has shorter wings. The bird has a distinctive yellow-tipped red bil ...

Atlantic petrel The Atlantic petrel (''Pterodroma incerta'') is a gadfly petrel endemic to the South Atlantic Ocean. It breeds in enormous colonies on Tristan da Cunha and Gough Island, and ranges at sea from Brazil to Namibia, with most records at sea being to ...

, and the

Inaccessible Island rail The Inaccessible Island rail (''Laterallus rogersi'') is a small bird of the rail family, Rallidae. Endemic to Inaccessible Island in the Tristan Archipelago in the isolated south Atlantic, it is the smallest extant flightless bird in the worl ...

.The only native reptiles are Tristiidon Sol and Tristiidon lunata. There are no native amphibians, freshwater fish, or land mammals.

Human settlement

Apart from Tristan da Cunha, which was settled as a base for

whaling Whaling is the process of hunting of whales for their usable products such as meat and blubber, which can be turned into a type of oil that became increasingly important in the Industrial Revolution. It was practiced as an organized industry ...

and sealing in the 18th century, the islands of the group are uninhabited except for a weather station on Gough Island belonging to

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

. Fishing is still an important economic activity especially for

crayfish Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mu ...

and

octopus An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttle ...

but also the

Tristan rock lobster ''Jasus paulensis'', also commonly known as the St Paul rock lobster, is a species of spiny lobster found in the waters around Saint Paul Island in the southern Indian Ocean and around Tristan da Cunha in the southern Atlantic Ocean. At one time ...

''(Jasus tristani)''. Gough Island has also been used as base for whaling and sealing but only ever temporarily. The islands do receive a small number of tourists.

Threats and preservation

Sheep and cattle have been introduced on Tristan da Cunha and their grazing, along with other human activity, has caused damage to the island's ecosystems. Night fishing has caused the deaths of many seabirds as they crash into ships' lights.Ryan, P. G. 1991. The impact of the commercial lobster fishery on seabirds at the Tristan da Cunha Islands, South Atlantic Ocean. Biological Conservation 57:339-350.

References

External links

* {{DEFAULTSORT:Geography Of Tristan Da Cunha