The polar deserts They are considered among the most extreme environments, as they include some of the coldest and driest habitats on the planet. They are defined as the areas of the northern polar caps (Arctic area) and southern (Antarctic area) of the Earth.
These areas have annual rainfall less than 250 mm and maximum temperatures below 10 °C. Desert is defined as a biome -bioclimatic zone- in which there is very little rainfall and few forms of life.
These elements include mosses, lichens, algae, microscopic invertebrates such as nematode worms, tardigrades and microarthropods (all smaller than 1mm in size), fish, birds and mammals, with little diversity but significant populations..
Article index
Although very similar, the climate of the Antarctic polar helmet is more extreme than that of the Arctic. Antarctica has an average summer temperature of -10 ° C; in winter the minimum drops to -83 ° C, and even at lower temperatures.
In the Arctic region the winter temperature reaches up to -45 ° C or -68 ° C. During the summer the average temperature is 0 ° C.
Both in Antarctica and in the Arctic there is a low rate of precipitation in the form of snow, in a range of 3 mm per year of liquid water equivalent in the inner continental areas and about 50 mm per year of liquid water equivalent in areas close to the coasts.
Most of the time, water in a liquid state is not biologically available and the conditions of low humidity in the air favor the evaporation of any rainwater and sublimation (passage from solid to gas) of the snow..
Other climatic characteristics are strong winds of up to 97 km / h and very low relative humidity..
Solar radiation strikes obliquely, steeply with respect to the surface and uninterruptedly for six months (spring and summer) of "polar day". The other six months of the year (autumn and winter) are of total darkness and originate the so-called "polar night".
The soils are usually infertile, formed by granites, sandstones, dolerites or black granite. These soils present alternation of freezing and thawing, are of high salinity, pH between neutral and alkaline and with very little organic matter. The ground may be frozen, which is often called permafrost.
It is dominated by glaciers, rocks, boulders, rock fragments, snow dunes, lakes covered in a perennial way by ice and very low flow, scarce and ephemeral streams of water..
Vegetation is sparse and generally dominated by cryptogams (plants that do not reproduce using seeds, such as mosses, liverworts, and lichens).
Coverage is poor (2%). This type of vegetation is particularly developed in Antarctica.
The diversity of flowering plants in the Arctic is much higher than in Antarctica, where there are only 2 species of phanerogams.
In the Arctic region there are extensive and dense covers, which in some areas are enriched with nutrients - such as the parts that are under cliffs and rocks where birds nest. This vegetation has no equivalent in Antarctica.
In the Arctic region there is a tundra zone and includes habitats dominated by small vascular plants, without significant growth of trees or grasses, except for the prostrate dwarf forms, such as the Arctic willow (Salix arctica), which is supported by permafrost.
In Antarctica there are herbs up to 2 m and mega herbs such as Stilbocarpa polaris Y Pringlea antiscorbutica.
In the Arctic region there are creeping dwarf shrubs such as the polar willow (Salix polaris), one of the smallest willows in the world that only reaches 2 to 9 cm in height. The arctic willow (Salix arctica), the miniature willow (Salix herbacea, grass 1 to 6 cm tall) and shrub Salix lanata.
Also described are dwarf birch plants (Betula nana), a bush 1 m tall; the little bush Dryas octopetala; Micranthes hieracifolia, small flowering plant 10-20 cm high; and the dwarf species Polemonium boreale.
Likewise, it presents the following herbs: Astragalus norvergicus, 40 cm tall; Draba lactea, that grows between 6 and 15 cm; Oxyria digyna, from 10 to 20 cm in size; arctic poppy Papaver radicatum; the sweet coltsfoot of the arctic Petasites frigidus, from 10 to 20 cm in height; and the Potentilla chamissonis, that reaches between 10 to 25 cm in size, among others.
In Antarctica, the scene of more extreme conditions, the vegetation is much smaller, due to the very low temperatures and the long periods without light, of total darkness..
Among the approximately 100 species of mosses reported, the endemic mosses stand out. Schistidium antarctici, Grimmia antarctici Y Sarconeurum glaciale.
75 species of fungi have been reported to develop in Antarctica; of these there are 10 macroscopic species that grow sporadically alongside mosses in the summer. There are also 25 species of liverworts, such as alga Prasolia crispa, among 700 other green and blue-green algae.
Among the woody plants, a few conifers belonging to the Podocarpaceae and Araucariaceae families develop; these are species of the Cunoniaceae and Atherospermataceae families. The southern beech trees also stand out (Nothofagus antarctica).
There are two endemic or native Antarctic vascular phanerogamic species: a grass, Antarctic grass, Antarctic hair grass, or Antarctic hair grass (Antarctic deschampsia); and the Antarctic pearl, Antarctic carnation or pearl grass (Colobanthus quitensis), with small white flowers. These are small and grow among the mosses.
The invertebrate fauna of the soil of the two terrestrial polar zones is distributed in patches. Includes protozoa, tardigrades, rotifers, nematodes, worms, mites, and collembola.
The Antarctic is home to a much lower diversity of insects than just two species of flies, while the Arctic has a variety of flies and beetles. Spiders also exist in the Arctic.
Most polar insects are not herbivores; feed on microorganisms and detritus (decomposing organic matter).
The presence of herbivorous vertebrates in the Arctic is a very important distinguishing factor between the two polar regions..
In the Arctic there are herbivores such as the small rodent lemino or arctic lemming (Dicrostonix torquatus) and the arctic hare (Lepus arctica), as well as larger species such as reindeer (Rangifer tarandus) and the musk oxenOvibus moschatus).
Large populations of migratory birds -like snow geeseChen caerulescens), the ptarmigan (Lagopus muta), the snow bunting (Plectrophenax nivalis) and the arctic gullsSterna paradisaea)- use the high arctic areas during the hot season to feed.
On the other hand, a particular factor in coastal Antarctic ecosystems is the concentration of seabirds and mammals in the reproductive, rearing or resting stages. The transfer of nutrients from these animal concentrations can fertilize and accelerate the development of vegetation and associated arthropod communities..
The fauna of the polar regions has adaptation mechanisms like those of mammals that develop dense coats and accumulate fat in the subcutaneous zone. Others live sheltered from the cold in underground tunnels and galleries, and some migrate during the months of lower temperatures..
Polar bears (Ursus maritimus), arctic wolves (Canis lupus arctos), arctic foxes (Vulpes lagopus), the musk ox (Ovibos moschatus), the caribou or reindeer (Rangifer tarandus), the arctic hare (Lepus articus) and the arctic lemming (Dicrostonix torquatus).
Among the Arctic marine fauna there are fish, mollusks and mammals such as baleen whales (Mysticeti spp.), belugasDelphinapterus leucas), seals (Phocidae family) and walruses (Odobenus rosmarus).
The primary herbivorous consumers are the arctic hare, musk ox, and caribou. The secondary consumers that prey on these herbivores are the arctic wolf and the fox. The polar bear is a predator of seals and fish.
In the Arctic there are few birds, and these are migratory, such as the Arctic tern or Arctic tern (Sterna paradisaea) -which migrates between the Arctic and Antarctica- and the snowy owl (Bubo candiacus).
The fauna of Antarctica is characterized by the low number of species (little diversity), but by a great richness in individuals. There are no terrestrial mammals or walruses like in the Arctic, nor amphibians or reptiles, but the marine fauna is the most abundant and varied on the continent.
Antarctic penguins of 5 species live in Antarctica. These include the emperor penguin (Aptenodytes forsteri) and the Adelie penguin (Pygoscelis adeliae). Both permanently inhabit this area.
There are also three migratory species: the gentoo penguin (Pygoscelis papua), king penguin (Aptenodytes patagonicus), and the chinstrap penguinPygoscelis antartica), which travel to less adverse climates during the winter.
The other birds of Antarctica are flying, such as the traveling or wandering albatross (Diomedea exulans), the polar skua (Catharacta maccormiki), the antarctic cormorant (Phalacrocorax bransfieldensis), the Dominican gull or cook (Larus dominicanus) and the brown gull or skúa (Catharacta skua).
There are also petrels such as the checkerboard or cape pigeon (Daption capense), which has black and white plumage; and the Antarctic giant petrelMacronectes giganteus). The Antarctic pigeon (Chionis alba) lives permanently in Antarctica.
The marine aquatic fauna is made up of some fish such as Antarctic cod (Notothenia corliceps Y Dissostichus mawsoni) and toothfish (Dissostichus eleginoides), crustaceans krill (Euphasia superba), seals and whales.
In Antarctica there are several species of seals: the Ross seal (Ommatophoca rossi), Weddell seal (Leptonychotes weddellii), the southern elephant seal (Mirounga leonina), the crabeater seal (Lobodon carcinophagus), the Antarctic fur seal (Arctocephalus gazella) and the sea leopard or leopard seal (Hydrurga leptonyx).
Among the species of whales that live in Antarctica are the blue whale (Balaenoptera musculus), fin whale or fin whale (Balaenoptera physalus), the Antarctic fin whaleBalaenoptera borealis) and the minke whale (Balaenoptera bonaerensis).
The humpback whale also stands out (Megaptera novaeangliae), the southern whale (Eubalaena glacialis) and toothed whales: sperm whale (Physeter macrocephalus, Physeter catodon), the orca (Orcinus orca) and the bottlenose whale or southern pilot whale (Hyperodon planifrons).
Yet No Comments