Bouvetøya is located at 54° 25′ S, 3° 21′ E, 2200 kilometres south of South Africa, 1600 kilometres from Gough Island and 1700 kilometres north of the coast of Queen Maud Land. The island is not part of Antarctica, which is defined as the area south of 60 °S.

The island measures only 49 square kilometres, and is almost entirely covered by ice. Steep cliffs on all sides of the island make it extremely difficult to go ashore there. Olavtoppen, 780 metres above sea level, is the highest peak on the island.

  • 1739

     

    Bouvetøya oppdaga

  • 1927

     

    Norsk anneksjon

  • 1928

     

    Status som norsk biland

  • 1935

     

    Alle selartane freda

  • 1971

     

    Status som naturreservat

Climate

Bouvetøya has a maritime Antarctic climate. Westerly winds dominate the area, but the wind strength is not particularly great. The average temperature at sea level is around -1 °C, and the monthly average is about 1 °C in January and -3 °C in September. The island is usually shrouded by cloud or dense fog. By a fluke, a Norwegian expedition in 1985 experienced completely clear skies long enough to photograph the entire island with a view to making a map.

Wildlife and vegetation

Vegetation

Mosses and lichens dominate the modest vegetation on Bouvetøya; fungi and algae are also present

Wildlife

The animal life on the island is dominated by seals, penguins and other seabirds that breed in colonies. There are large colonies of Antarctic fur seals on the island and some elephant seals. Twelve species of birds breed on the island.

Hunting of fur seals was banned in 1929, and in 1935 all the seal species in the area were protected. Bouvetøya and its territorial waters were designated a nature reserve in 1971, thus ensuring the rich and characteristic plant and animal life on the island full protection.

Three seals

One of the fur seal families on Bouvetøya. Photo: Martin Biuw / Norwegian Polar Institute

The fur seal colony in the monitoring area at Nyrøysa increased from 7900 individuals to as many as 65 000 individuals between 1990 and 1997. The population seems to have stabilised since then, probably due to a lack of suitable areas.

In the same period, there was a considerable decline in the penguin colonies, especially involving the chinstrap penguins. In 1990, 2700 and 5900 chinstrap and macaroni penguins, respectively, were recorded, but in 1997 these numbers were reduced to 422 and 4700. Here, too, only small changes seem to have occurred since 2000.

The changes in the penguin populations are probably linked to the big increase in the fur seal population, the seals having taken over penguin territory. Fur seals are growing in numbers throughout Antarctica, and the population seems to have recovered after the species ceased to be hunted.

Several of the Red Listed species covered by the ACAP-agreement (Agreement on the Conservation of Albatrosses and Petrels) are found around Bouvetøya. Only one of these, the southern giant petrel (Macronectes giganteus), has been recorded breeding on the island.

 

History

Bouvetøya was discovered by a Frenchman, Jean-Baptiste Lozier Bouvet, as early as 1739, but many years passed before it was rediscovered. The first of a series of Norwegian expeditions to Antarctica took place in 1927-28. It was funded by Lars Christensen. The expedition vessel was named “Norvegia”, so the expeditions have since been known as the “Norvegia” expeditions. They went ashore on 1 December 1927, hoisted the Norwegian flag and claimed Bouvet Island as Norwegian territory. The United Kingdom disagreed since it had claimed sovereignty as early as 1825. Following some diplomatic activity, Britain waived its claim in 1929.

Geologi

Bouvetøya er en vulkanøy, ca. 10 km lang og 7,5 km bred, og med en 2 × 3 km stor kaldera (vulkansk krater) i den nordvestlige delen av øya. Høyeste punkt er Olavtoppen med 780 moh. Det meste av øya, ca. 95 %, er dekket av is.

Blotninger av fast fjell finnes langs kysten og i fjellveggene rett over brenningssonen. I nord og vest er de blottede veggene opp til 500 m høye. Det er her det meste av brenningserosjonen foregår pga. de permanente vestlige vindene. Dette er også grunnen for vulkanøyas asymmetriske form; vulkankjeglen er bare bevart i syd og øst.

Vulkanøya ligger på den sørligste delen av den midtatlantiske ryggen og er lokalisert like øst for Bouvet-treriftspunktet (triple junction) – et punkt hvor tre oseaniske riftsystemer møter hverandre. Øya utgjør toppen av en undersjøisk vulkan. De eldste undersjøiske bergartene er omlag 4,5–5 millioner år gammel, mens de eldste bergartene over havnivå er datert til omkring 1,4 million år gamle.

Bouvetøya har en todelt stratigrafi. Den eldste og nedre formasjon består hovedsakelig av ulike typer pyroklastiske bergarter som mest sannsynlig er dannet som submarin hyaloklastitt. Den yngste og øvre formasjonen består av lava, samt mindre mengder vulkanoklastiske avsetninger. De vulkanske bergartene har i hovedsak basaltisk sammensetning, de yngste lavastrømmene har imidlertid rhyolittisk sammensetning. Kapp Valdivia består av en yngre rhyolittisk lava dome.

I dag er den vulkanske aktiviteten er begrenset til fumaroler som opptrer mange steder på nord- og nordvestkysten som ligger nærmest kalderaen. Det finnes ingen historiske beretninger om vulkanutbrudd. Nyrøysa, en kystslette nordvest på øya, ble til mellom 1955 og 1958. Bergartene som danner Nyrøysa er 0,4–0,5 millioner år gamle, og man antar at plattformen er dannet som et resultat av ras. Det finnes historiske observasjoner av andre øyer i nærheten av Bouvetøya, som Lindsay- og Thompsonøya. Den siste antas å være ødelagt av en vulkansk eksplosjon i 1895.

kart over Bouvetøya

Bouvetøya in the Southern Ocea
Map: Norwegian Polar Institute

  • 1739

     

    Bouvetøya discovered

  • 1927

     

    Norwegian annexation

  • 1928

     

    Status as Norwegian dependency

  • 1935

     

    Seals are protected by law

  • 1971

     

    Status as a nature reserve