We explain what the desert is and the different climates that predominate in this biome. In addition, the flora and fauna that it houses.
What is the desert?
Desert is understood to be a bioclimatic landscape (or biome) characterized by its very low precipitation rates (rains) and therefore very narrow humidity margins, which translates into dry climates, extreme temperatures and arid soils.
Traditionally they have been thought of as places devoid of lifeAlthough this is not necessarily the case: there is a flora (xerophilous) and a fauna (and also human populations) that have known how to adapt to these harsh living conditions.
Currently deserts occupy almost a third of the surface of our planet, which represents a total area of more or less 50 million km2, of which 53% correspond to hot deserts (such as the Sahara) and the rest to frozen deserts (such as Antarctica).
They are distributed throughout the five continents, with the best known regions being those of North Africa, North Mexico, the Russian tundra, the frozen plains of Greenland and Alaska, as well as the North of Chile and the southern Argentina.
In deserts, wind erosion (wind) and solar radiation are usually very intense, so the soil is usually sandy, stony or rocky; and in the case of the polar deserts of the Antarctic, it is made up of a dense layer of frozen soil (permafrost). Many characteristics of the desert will depend on the degree of intensity of these factors, such as the type of sand formed or the climatic dynamics that it presents.
Desert climate
It is possible to recognize three different climatic types in deserts, taking into account their average annual rainfall, which in any case is usually lower than in the rest of the regions of the planet. Can we talk about:
- Semi-arid climates (steppe). They have an average of 250 to 500 mm of rain per year and constitute 15% of the Earth’s surface. They are usually found only on the outer edges of deserts proper.
- Arid climates. With annual rainfall between 25 and 250 mm (maximum), they cover 16% of the planet’s surface and are found in the bulk of known deserts.
- Hyper-arid climates. The drought in these regions is such that it does not usually rain for years. Fortunately, they constitute only 4% of the planetary surface, and are limited to the polar deserts (too icy for liquid water) or to the very heart of the great hot deserts.
Temperatures in deserts are often extreme, with enormous temperature variation between day and night. In hot deserts you can record a maximum of more than 40 degrees Celsius during the day and at night falling below zero.
If we refer to the polar deserts, the temperature is always very low (around -40 ° C) and depending on the stationary cycle it can rise during the summer to almost 0 ° C.
Desert plants
The flora of deserts is very particular, and in principle scarce, due to the very low humidity levels: without water it is impossible to carry out photosynthesis.
However, life has adapted to such adverse conditions: xerophilous vegetation has a predominance of thorny, fleshy and resistant plants, similar to the cactus (cactus), with a large storage capacity of the received water. The rest are dominated by weeds and, in the best of cases, short shrubs.
In the occasional oases, on the other hand, the standing water allows a greater proliferation of plant life, and it is possible to observe palm trees and taller shrubs, even fruit trees such as dates or coconut.
Desert animals
Contrary to what used to be thought, there are animals in the desert, adapted to the environment and focused on preserving their body moisture.
In hot deserts, reptiles (snakes, lizards), insects (ants, beetles) and arachnids (scorpions, spiders) abound. Too there are numerous desert rodents, which take refuge in burrows to get away from the daytime sun, of which emerge only at night when everything cools down. Birds of prey and scavengers feed on them. Finally, it is possible to find camelids (camels, dromedaries) with very high resistance to drought.
Frozen deserts, on the other hand, are less generous with life, and apart from mosses and bacterial life, there are usually not too many animals. In the outermost regions of the same, on the other hand, it is possible to find polar fauna: bears, seals and other mammals with insulating skin and lots of stored fat, killer whales and whales, and fish, plankton and penguins that feed them.