90°00′S0°00′W / 90.000°S -0.000°E /-90.000; -0.000
TheAntarctic realm is one of eight terrestrialbiogeographic realms. The ecosystem includesAntarctica and several island groups in the southernAtlantic andIndian 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 250lichens, 100mosses, 25–30liverworts, and around 700 terrestrial and aquaticalgal 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 theAntarctic Peninsula. Antarctica is also home to a diversity of animal life, includingpenguins,seals, andwhales.
Several Antarctic and sub-Antarctic island groups are considered part of the Antarctic realm, includingBouvet Island, theCrozet Islands,Heard Island, theKerguelen Islands, theMcDonald Islands, thePrince Edward Islands, theSouth Georgia Group, theSouth Orkney Islands, theSouth Sandwich Islands, and theSouth Shetland Islands. These islands have a somewhat milder climate than Antarctica proper, and support a greater diversity oftundra plants, although they are all too windy and cold to support trees.
Antarctic krill is thekeystone species of the ecosystem of theSouthern Ocean, and is an important food organism forwhales,seals,leopard seals,fur seals,crabeater seals,squid,icefish,penguins,albatrosses and many otherbirds. The ocean there is so full ofphytoplankton because water rises from the depths to the light-flooded surface, bringingnutrients from all oceans back to thephotic zone.
On August 20, 2014, scientists confirmed the existence ofmicroorganisms living 800 metres (2,600 feet) below the ice ofAntarctica.[1][2]
Millions of years ago, Antarctica was warmer and wetter, and supported theAntarctic flora, including forests ofpodocarps andsouthern beech. Antarctica was also part of the ancient supercontinent ofGondwanaland, which gradually broke up bycontinental drift starting 110 million years ago. The separation ofSouth America from Antarctica 30–35 million years ago allowed theAntarctic 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 southernNeotropical (Latin America and the Caribbean) andAustralasian realms, which were also former parts of Gondwana.
Some botanists recognize anAntarctic Floristic Kingdom that includes Antarctica,New Zealand, and parts of Temperate South America where the Antarctic Flora is still a major component.
The Antarctic realm is divided into 17tundraecoregions:[3]
