Antarctic realm

Last updated

90°00′S0°00′W / 90.000°S -0.000°E / -90.000; -0.000

Contents

The Antarctic realm (in green) LocationAntarctica.png
The Antarctic realm (in green)

The Antarctic realm is one of eight terrestrial biogeographic realms. The ecosystem includes Antarctica and several island groups in the southern Atlantic 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 lichens, 100 mosses, 25–30 liverworts, and around 700 terrestrial and aquatic algal 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 ) and Antarctic pearlwort ( Colobanthus quitensis ), are found on the northern and western parts of the Antarctic Peninsula. Antarctica is also home to a diversity of animal life, including penguins, seals, and whales.

Several Antarctic and sub-Antarctic island groups are considered part of the Antarctic realm, including Bouvet Island, the Crozet Islands, Heard Island, the Kerguelen Islands, the McDonald Islands, the Prince Edward Islands, the South Georgia Group, the South Orkney Islands, the South Sandwich Islands, and the South Shetland Islands. These islands have a somewhat milder climate than Antarctica proper, and support a greater diversity of tundra plants, although they are all too windy and cold to support trees.

Antarctic krill is the keystone species of the ecosystem of the Southern Ocean, and is an important food organism for whales, seals, leopard seals, fur seals, crabeater seals, squid, icefish, penguins, albatrosses and many other birds. The ocean there is so full of phytoplankton because water rises from the depths to the light-flooded surface, bringing nutrients from all oceans back to the photic zone.

On August 20, 2014, scientists confirmed the existence of microorganisms living 800 metres (2,600 feet) below the ice of Antarctica. [1] [2]

History

Millions of years ago, Antarctica was warmer and wetter, and supported the Antarctic flora, including forests of podocarps and southern beech. Antarctica was also part of the ancient supercontinent of Gondwanaland, which gradually broke up by continental drift starting 110 million years ago. The separation of South America 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 (Latin America and the Caribbean) and Australasian realms, which were also former parts of Gondwana.

Some botanists recognize an Antarctic Floristic Kingdom that includes Antarctica, New Zealand, and parts of Temperate South America where the Antarctic Flora is still a major component.

Ecoregions

The Antarctic realm is divided into 17 tundra ecoregions: [3]

Adelie Land tundra Adélie Land
Central South Antarctic Peninsula tundra Antarctic Peninsula
Dronning Maud Land tundra Queen Maud Land
East Antarctic tundra Eastern Antarctica
Ellsworth Land tundra Ellsworth Land
Ellsworth Mountains tundra Ellsworth Mountains
Enderby Land tundra Enderby Land
Marie Byrd Land tundra Marie Byrd Land
North Victoria Land tundra Victoria Land
Northeast Antarctic Peninsula tundra Antarctic Peninsula
Northwest Antarctic Peninsula tundra Antarctic Peninsula
Prince Charles Mountains tundra Prince Charles Mountains
Scotia Sea Islands tundra South Georgia and the South Sandwich Islands, South Shetland Islands, Bouvet Island
South Antarctic Peninsula tundra Antarctic Peninsula
South Orkney Islands tundra South Orkney Islands
South Victoria Land tundra Victoria Land
Southern Indian Ocean Islands tundra Crozet Islands, Prince Edward Islands, Heard Island, Kerguelen Islands, McDonald Islands
Transantarctic Mountains tundra Transantarctic Mountains

Related Research Articles

<span class="mw-page-title-main">Antarctic</span> Polar region around Earths South Pole

The Antarctic is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole.

<span class="mw-page-title-main">Tundra</span> Biome where plant growth is hindered by frigid temperatures

In physical geography, 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 tundra, alpine tundra, and Antarctic tundra.

<span class="mw-page-title-main">Antarctic flora</span> Distinct community of plants which evolved on the supercontinent of Gondwana

Antarctic flora are a distinct community of vascular plants which evolved millions of years ago on the supercontinent of Gondwana. Presently, species of Antarctica flora reside on several now separated areas of the Southern Hemisphere, including southern South America, southernmost Africa, New Zealand, Australia, and New Caledonia. Joseph Dalton Hooker was the first to notice similarities in the flora and speculated that Antarctica had served as either a source or a transitional point, and that land masses now separated might formerly have been adjacent.

<span class="mw-page-title-main">Magellanic subpolar forests</span> Ecoregion of southernmost South America

The Magellanic subpolar forests are a terrestrial ecoregion of southernmost South America, covering parts of southern Chile and Argentina, and are part of the Neotropical realm. It is a temperate broadleaf and mixed forests ecoregion, and contains the world's southernmost forests.

<span class="mw-page-title-main">Elephant Island</span> Island off the coast of Antarctica

Elephant Island is an ice-covered, mountainous island off the coast of Antarctica in the outer reaches of the South Shetland Islands, in the Southern Ocean. The island is situated 245 kilometres north-northeast of the tip of the Antarctic Peninsula, 1,253 kilometres west-southwest of South Georgia, 935 kilometres south of the Falkland Islands, and 885 kilometres southeast of Cape Horn. It is within the Antarctic claims of Argentina, Chile and the United Kingdom.

<span class="mw-page-title-main">Antarctic Peninsula</span> Peninsula located in northern Antarctica

The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín 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.

<span class="mw-page-title-main">South Orkney Islands</span> Group of islands in the Southern Ocean north-east of the Antarctic Peninsula

The South Orkney Islands are a group of islands in the Southern Ocean, about 604 km (375 mi) north-east of the tip of the Antarctic Peninsula and 844 km (524 mi) south-west of South Georgia Island. They have a total area of about 620 km2 (240 sq mi). The islands are claimed both by Britain, and by Argentina as part of Argentine Antarctica. Under the 1959 Antarctic Treaty, sovereignty claims are held in abeyance.

<span class="mw-page-title-main">Scotia Sea</span> Sea in the Southern Ocean

The Scotia Sea is a sea located at the northern edge of the Southern Ocean at its boundary with the South Atlantic Ocean. It is bounded on the west by the Drake Passage and on the north, east, and south by the Scotia Arc, an undersea ridge and island arc system supporting various islands. The sea sits atop the Scotia Plate. It is named after the expedition ship Scotia. Many icebergs melt there.

<span class="mw-page-title-main">Antipodes Subantarctic Islands tundra</span> Ecoregion

The Antipodes Subantarctic Islands tundra ecoregion, within the tundra biome, includes five remote island groups in the Pacific Ocean south of New Zealand: the Bounty Islands, Auckland Islands, Antipodes Islands and Campbell Island groups of New Zealand, and Macquarie Island of Australia.

Polar ecology is the relationship between plants and animals in a polar environment. Polar environments are in the Arctic and Antarctic regions. Arctic regions are in the Northern Hemisphere, and it contains land and the islands that surrounds it. Antarctica is in the Southern Hemisphere and it also contains the land mass, surrounding islands and the ocean. Polar regions also contain the subantarctic and subarctic zone which separate the polar regions from the temperate regions. Antarctica and the Arctic lie in the polar circles. The polar circles are imaginary lines shown on maps to be the areas that receives less sunlight due to less radiation. These areas either receive sunlight or shade 24 hours a day because of the earth's tilt. Plants and animals in the polar regions are able to withstand living in harsh weather conditions but are facing environmental threats that limit their survival.

<span class="mw-page-title-main">East Antarctica</span> Part of Antarctica that lies within the Eastern Hemisphere

East Antarctica, also called Greater Antarctica, constitutes the majority (two-thirds) of the Antarctic continent, lying primarily in the Eastern Hemisphere south of the Indian Ocean, and separated from West Antarctica by the Transantarctic Mountains. It is generally greater in elevation than West Antarctica, and includes the Gamburtsev Mountain Range in the center. The geographic South Pole is located within East Antarctica.

The Kerguelen Islands are part of the Southern Indian Ocean Islands tundra ecoregion that includes several subantarctic islands. In this cold climate plant life is mainly limited to grasses, mosses and lichens, although the islands are also known for the indigenous edible Kerguelen cabbage. The islands are at the Antarctic Convergence, where cold water moving up from the Antarctic mixes with the warmer water of the Indian Ocean. As a consequence, marine mammals, especially seals, and seabirds and penguins are numerous.

<span class="mw-page-title-main">Southern Indian Ocean Islands tundra</span> Ecoregion of several subantarctic islands in the southern Indian Ocean

The Southern Indian Ocean Islands tundra is a tundra ecoregion that includes several subantarctic islands in the southern Indian Ocean.

<span class="mw-page-title-main">Scotia Sea Islands tundra</span> Tundra ecoregion

The Scotia Sea Islands tundra is a tundra ecoregion which includes several island groups – South Georgia and the South Sandwich Islands, South Shetland Islands, and Bouvet Island – in the Scotia Sea, where the South Atlantic Ocean meets the Southern Ocean. Most of the terrain is covered with snow and permanent ice, with tundra vegetation - moss, lichen, and algae - on the remainder. The islands support important rookeries for seals, seabirds, and penguins. The islands have no permanent human habitation, and the cold, harsh climate and ending of seal hunting and whaling has prevented settlement.

<span class="mw-page-title-main">Byers Peninsula</span> Peninsula in the South Shetland Islands of Antarctica

Byers Peninsula is a mainly ice-free peninsula forming the west end of Livingston Island in the South Shetland Islands of Antarctica. It occupies 60 km2 (23 sq mi), borders Ivanov Beach to the northeast and is separated from Rotch Dome on the east by the ridge of Urvich Wall. The peninsula features more than 60 meltwater streams and as many lakes, notably Midge Lake, Limnopolar Lake and Basalt Lake. Byers Peninsula has a regime of special environmental protection under the Antarctic Treaty System and requires a permit to enter.

<span class="mw-page-title-main">Southern Ocean</span> Ocean around Antarctica

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. With a size of 21,960,000 km2 (8,480,000 sq mi), it is the second-smallest of the five principal oceanic divisions, smaller than the Pacific, Atlantic and Indian oceans, and larger than the Arctic Ocean.

<span class="mw-page-title-main">Amsterdam and Saint-Paul Islands temperate grasslands</span> Ecological region in the southern Indian Ocean

The Amsterdam and Saint-Paul Islands temperate grasslands is a temperate grasslands, savannas, and shrublands ecoregion comprising Île Amsterdam and Île Saint-Paul, two volcanic islands in the southern Indian Ocean.

<span class="mw-page-title-main">Wildlife of Antarctica</span> Antarctic wildlife

The wildlife of Antarctica are extremophiles, having adapted to the dryness, low temperatures, and high exposure common in Antarctica. The extreme weather of the interior contrasts to the relatively mild conditions on the Antarctic Peninsula and the subantarctic islands, which have warmer temperatures and more liquid water. Much of the ocean around the mainland is covered by sea ice. The oceans themselves are a more stable environment for life, both in the water column and on the seabed.

The Biodiversity of South Africa is the variety of living organisms within the boundaries of South Africa and its exclusive economic zone. South Africa is a region of high biodiversity in the terrestrial and marine realms. The country is ranked sixth out of the world's seventeen megadiverse countries, and is rated among the top 10 for plant species diversity and third for marine endemism.

References

  1. Fox, Douglas (August 20, 2014). "Lakes under the ice: Antarctica's secret garden". Nature . 512 (7514): 244–246. Bibcode:2014Natur.512..244F. doi: 10.1038/512244a . PMID   25143097.
  2. Mack, Eric (August 20, 2014). "Life Confirmed Under Antarctic Ice; Is Space Next?". Forbes . Retrieved August 21, 2014.
  3. 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

Bibliography