What is a desert?
The desert is an area of extremely dry land with little rainfall. It is one of the most important biomes on Earth given the variety of plants and animals adapted to living in such conditions.
Deserts cover about a fifth of the Earth's surface, and can be found on every continent on Earth. Therefore, it is possible to differentiate between hot deserts, cold deserts, mountainous deserts, coastal deserts and semi-arid deserts.
In deserts, flora and fauna are scarce due to little water and the high temperatures in which they develop.
These biomes receive about 25 cm of rain per year, which makes it difficult for living things to survive. However, many species have adapted to living under the extreme temperatures and aridity of the soils that characterize them, using techniques that allow them to overcome the aggressiveness of the environment.
Characteristics of the desert
Lack of water
The lack of water is due to the fact that rainfall is scarce and barely reaches 25 cm per year, it may even be a lower value. Low atmospheric humidity, high temperatures during the day and strong winds also lead to a lack of water.
In hot deserts during the day temperatures can reach as high as 50 ° C, and at night they can drop to 0 ° or -10 ° C. In polar deserts temperatures are usually below zero, and can reach - 50 ° C.
Deserts cover about a fifth of the planet. Hot deserts are located in the tropical and temperate latitudes of an area of the equator. However, there are also deserts in other areas such as Argentina, North Africa, Asia, Australia, Chile, the United States, Mexico, Russia, among others.
Cold deserts are located in the polar areas of the Arctic and Antarctic, for example, Greenland.
There are three areas that are:
- Semi-arid or steppe areas: they are located on the edges of deserts and have an average rainfall between 250 and 500 mm.
- Arid zone: annual rainfall is between 25 and 250 mm.
- Hyper-arid zone: these are those areas in which several years can pass without rain, such as in deserts located in polar areas or in the center of large hot deserts.
Flora and fauna
The flora and fauna of deserts is made up of plants and animals adapted to survive under extreme climatic conditions. They are species very vulnerable to climatic changes and other human activities that affect deserts and cause desertification processes.
The relief of the deserts is characterized by having:
- Dunes: mounds of sand that are formed by the wind when layers of sand that accumulate together. They can be found in coastal deserts and in the interior of great deserts.
- Plains: they are large extensions of flat land that can present undulations due to the dunes. They can be seen in both hot and cold deserts.
- Salinas: they are located in areas that in the past were lakes or ponds of salt water and that dried up leaving large deposits of salt at the bottom.
- Plateaus: these are elevations with flat tops and steep slopes in the middle of the desert.
Desert soils vary according to the erosion processes that affect a particular area. Therefore, it is possible to differentiate sandy soils composed mainly of sand, and rocky or stony deserts whose lands are composed of stones.
Various human activities contribute to the growth of desert spaces. For example, agricultural activities contribute to the desertification of soils due to grazing and the incorrect use of water resources in various areas.
However, millions of people live in desert areas adapted for the development of various social, economic and cultural activities.
An example of this are the United Arab Emirates, and other regions of America, Africa and Asia where even nomadic groups dedicated to grazing are still found in areas surrounding the oases.
The desert ecosystem is made up of various species of plants and animals adapted to living in areas of extreme drought and aridity.
The flora in deserts is scarce because plants can spend a long time, even years, receiving rain or fresh water. Therefore, the vegetation cover of these biomes is low or almost non-existent.
Plant formations are characterized by having short life cycles or being resistant to the extreme environmental conditions of deserts.
Xerophilic plants, for example, are adapted to the absence of water. These plants have adapted by having long roots that extend to extract, store and conserve underground water in their stems.
Some examples of desert flora are succulent plants like cacti that store water in their spines and stems. You can also see medium bushes, mesquite grass, among others. Even some desert plants can sprout and flourish in rainy seasons.
In cold deserts there are also few plants due to low temperatures, periods of low light and lack of rainfall. Among the plants that develop in these areas are dwarf shrubs such as the polar willow, various types of moss, among others.
The fauna of hot deserts is made up of animals adapted to living in extreme conditions. They have developed techniques that allow them to live with little water and stay cool. For example, camels can go weeks without drinking water because their eyelashes and nostrils form a barrier against sand.
Other animals spend much of their sunny hours underground or hiding among rocks, and hunt at night when temperatures drop.
The desert fauna is composed of snakes, lizards, beetles, ants, arachnids, birds, vultures, mice, foxes, camels, dromedaries, mice, among others.
In cold deserts, animals are adapted to living under very low temperatures and with little light in certain periods of the year.
Among the species of animals that live in these conditions are the polar bear, penguins, migratory birds, arctic foxes, arctic hare, reindeer, among others.
- What is a biome?
Types of desert
- Warm desert: it consists of little rainfall and high temperatures throughout the year that can reach 50º C. They are located near the equator and are characterized by having very hot soils. For example, the largest hot desert on Earth is the Sahara, in North Africa.
- Semi-arid desert: it is a type of moderately dry desert, with temperatures between 21 and 38º C during the day. Precipitation is scarce but higher than in hot deserts. For example, the desert of Montana in the United States.
- Coastal desert: characterized by the occurrence of fog, it is associated with cold sea currents that cause temperature inversion and condensation. Average temperatures are between 13 and 24º C. For example, the Atacama desert in Chile.
- Cold desert: they are snow-covered deserts, with annual rainfall of less than 250 mm. Average temperatures are between -2 and -26º C. For example, the Greenland desert and Antarctica. In these areas are the tundras, biomes that resemble cold deserts.
- Flowery desert: it occurs in the Atacama desert, in Chile, the most sterile on the planet. Its name is due to the appearance of various flowers between the months of September and November, in those years when rainfall is unusual.
What are the largest deserts on Earth?
- Sahara Desert: known as the hottest desert in the world. It is located throughout the northern strip of the African continent.
- Gobi Desert: It extends in the southern part of Mongolia and northern China. It has rich wildlife and an extreme climate.
- Sonoran Desert: It is located between the United States and Mexico, covering large parts of Arizona and California.
- Lençois Maranhenses Desert: it is a desert of white dunes, located in Brazil. The accumulations of water that form between June and September as a result of the rains are curious and spectacular.
- Atacama Desert: located in the north of Chile, it is considered the driest desert in the world.
- Polar deserts of the Arctic and Antarctic: They are located in the polar areas and are the largest of this type.
Oases are geographic points in deserts where water and vegetation can be found. For this reason, there may be settlements of people who live around them, such as nomads, since they can carry out the activities of herding and agriculture.
Oases can be found in the desert of Ica, Peru, Pica, Chile and in various areas of the Sahara in Africa.