Deserts and semi-deserts: soil, climate, fauna

Deserts of the semi-desert are dry, dry regions of the planet, where no more than 25 cm of precipitation a year falls. The most important factor in their formation is the wind. However, not all deserts are experiencing hot weather, some of them, on the contrary, are considered the coldest regions of the Earth. Representatives of flora and fauna have differently adapted to the harsh conditions of these areas.

How do deserts and semi-deserts arise?

The reasons for creating deserts are many. For example, in the Atacama Desert, there is little rainfall because it is located at the foot of the mountains, which cover it from the rain with its crests.

Ice deserts formed for other reasons. In Antarctica and the Arctic, the main snow mass falls on the coast, to the interior regions, snow clouds barely reach. The level of precipitation mostly varies greatly, for one snowfall, for example, an annual rate may fall. Such snow drifts are formed over hundreds of years.

Hot deserts are very diverse relief. Only some of them are completely covered with sand. The surface of the majority is strewn with pebbles, stones and other different breeds. Deserts are almost completely open to weathering. Strong gusts of wind pick up fragments of small stones and strike them against the rocks.

In sand deserts, the wind carries sand through the territory, creating undulating deposits called dunes. The most common type of dunes is dunes. Sometimes their height can reach 30 meters. The crest dunes can have a height of 100 meters and extend for 100 km.

Temperature conditions

The climate of deserts and semi-deserts is quite diverse. In some regions, daytime temperatures can reach up to 52 ° C. This phenomenon is due to the absence of clouds in the atmosphere, thus, nothing saves the surface from direct sunlight. At night, the temperature is greatly reduced, which again is explained by the absence of clouds, which are capable of delaying the heat radiated by the surface.

In hot deserts, rain is a rare phenomenon, but sometimes there are strong showers here. After the rain, the water does not soak into the ground, but quickly flows from the surface, washing away particles of soil and pebbles in the dry canals, which are called wadi.

Location of deserts and semi-deserts

On the continents, which are located in the northern latitudes, there are deserts and semi-deserts of the subtropical and temperate zones. Sometimes also there are tropical ones - in the Indo-Gangetic lowland, in Arabia, in Mexico, in the south-west of the USA. In Eurasia, extratropical desert regions are located in the Caspian lowland, in the Central Asian and South Kazakh plains, in the basin of Central Asia and in the Upper Asian highlands. Central Asian desert formations are characterized by sharply continental climate.

In the southern hemisphere, deserts and semi-deserts occur less frequently. Such desert and semi-desert formations as Namib, Atacama, desert formations on the coast of Peru and Venezuela, Victoria, Kalahari, Gibson Desert, Simpson, Gran Chaco, Patagonia, the Great Sand Desert and the Carrh semi-desert in south-west Africa are located here.

The polar deserts are located on the continental islands of the preglacial regions of Eurasia, on the islands of the Canadian archipelago, in the north of Greenland.

Animals

Animals of deserts and semi-deserts for many years of existence in such localities have managed to adapt to severe climatic conditions. From the cold and heat, they hide in underground burrows and feed, mainly, underground parts of plants. Among the representatives of the fauna there are many species of carnivores: fox fox, reed cats, cougars, coyotes and even tigers. The climate of deserts and semi-deserts contributed to the fact that many animals developed thermoregulation system perfectly. Some inhabitants of deserts can withstand the loss of fluid to a third of their weight (for example, geckos, camels), and among invertebrates there are species that are able to lose water to two thirds of their weight.

In North America and Asia, there are a lot of reptiles, especially many lizards. Quite common are snakes: ephi, various poisonous snakes, boa-worms. From large animals there are saigas, kulans, camels, hornhorn, just recently the horse of Przhevalsky disappeared (in captivity it can still be found).

Animals of the desert and semi-deserts of Russia are a great variety of unique fauna. In the desert regions of the country there live hares-sandstones, hedgehogs, kulan, jayman, poisonous snakes. In the deserts that are on the territory of Russia, you can also meet 2 types of spiders - karakurt and tarantula.

Polar deserts are inhabited by a polar bear, a musk ox, an arctic fox and some species of birds.

Vegetation

If we talk about vegetation, then in the deserts and semi-deserts, there are various cactus, hard-leaved grasses, psammophytes, ephedra, acacia, saxaul, soap , date palm, edible lichen and others.

Deserts and semi-deserts: soil

Soil, as a rule, is poorly developed, water-soluble salts predominate in its composition. Old-alluvial and loess-like deposits predominate among the soil-forming rocks, which are processed by winds. Gray-brown soil is inherent in the elevated plains. Deserts are also characterized by solonchaks, that is, soils that contain about 1% of readily soluble salts. In addition to deserts, solonchaks are also found in steppes and semi-deserts. Groundwater, which contains salts, when deposited on the soil surface is deposited in its upper layer, resulting in salinization of the soil.

Absolutely other types of soils are characteristic of such climatic zones as subtropical deserts and semi-deserts. The soil in these regions has a specific orange and brick-red color. Noble to its shades, it received the appropriate name - krasnozem and yellow. In the subtropical belt in northern Africa and in the South and North America there are deserts where gray soils were formed. In some tropical desert formations, red-yellow soils were formed.

The natural zones of deserts and semi-deserts are a huge variety of landscapes, climatic conditions, flora and fauna. Despite the harsh and cruel temper of the deserts, these regions have become a home for many species of plants and animals.