A biome is a large ecological area defined by its distinct climate, plants, and animal life. This region forms in response to its physical environment and climate. Antarctica is one of Earth’s most extreme environments, influencing the life that can inhabit its vast expanse.
Antarctica’s Biome Classification
Antarctica is predominantly classified as a polar desert. A desert is defined by the extremely low amount of annual precipitation it receives. The continent receives an average of 150 to 166 millimeters (6-6.5 inches) of water equivalent precipitation each year, primarily as snow or ice crystals. Areas receiving less than 250 millimeters annually are generally categorized as deserts.
The continent’s interior is exceptionally dry, often receiving less than 50 millimeters (2 inches) of precipitation per year, while coastal regions can receive slightly more. Roughly 98% of Antarctica’s landmass is covered by a thick ice sheet, but this frozen water is largely unavailable for biological processes. Conversely, limited ice-free areas, particularly along the Antarctic Peninsula and on sub-Antarctic islands, are polar tundra. Here, a milder climate supports low-growing plants like mosses and lichens.
Defining Characteristics of the Antarctic Biome
Antarctica is the coldest, driest, and windiest continent on Earth. Temperatures are exceptionally low, with the lowest recorded air temperature reaching -89.2 °C (-128.6 °F) at Vostok Station. The mean annual temperature in the interior typically hovers around -43.5 °C (-46.3 °F), while coastal areas average around -10 °C (14 °F). This cold contributes to the continent’s ice sheets, which hold approximately 90% of the world’s ice and over 70% of its freshwater, with an average thickness of 1.9 kilometers (1.2 miles).
The continent’s aridity is due to low precipitation rates, with rain rare and mostly confined to summer in coastal areas. The air is also dry due to frigid temperatures, limiting moisture. Powerful katabatic winds are another defining feature. These winds form when cold, dense air, chilled over ice sheets, flows downslope. Consistent winds can reach speeds exceeding 100 kilometers per hour (62 mph) for days, with gusts over 240 kilometers per hour (150 mph).
Life Thrives in the Antarctic Extreme
Antarctica supports life adapted to its extreme environment. Terrestrial life is largely confined to small ice-free zones. Here, resilient organisms like microscopic life forms, algae, mosses, and lichens are found. Only two flowering plant species, Antarctic hair grass and Antarctic pearlwort, grow in the milder Antarctic Peninsula. Small invertebrates such as mites, nematodes, springtails, tardigrades, and the flightless midge Belgica antarctica represent some of the largest land animals. These organisms exhibit adaptations like retaining moisture, tolerating frost, and producing antifreeze chemicals.
The marine environment surrounding Antarctica, the Southern Ocean, is richer in biodiversity than the land. Microscopic phytoplankton form the base of the food web, thriving in cold, nutrient-rich waters. These support vast populations of Antarctic krill, a keystone species, which serve as a primary food source for whales, seals, penguins, and fish. Marine life adapts to the cold with features like thick blubber in seals, penguins, and whales for insulation. Many Antarctic fish, including icefish, produce antifreeze proteins in their blood, while penguins have dense, water-repellent feathers and some species, like Emperor penguins, huddle for warmth.