Deserts are among the most arid and biodiversity-poor ecosystems on the planet. There are numerous types of deserts, and much about them is often talked about lightly. However, many people don't know... what is a desert and what the unique characteristics of these ecosystems are. Furthermore, it's important to highlight that deserts are threatened by climate change, which affects their biodiversity and ecosystems.
For this reason, we are going to dedicate this article to telling you what a desert is, its characteristics and types.
what is a desert
A desert is a bioclimatic landscape (or biome), hot or cold, characterized by low precipitation rates, dry climates, extreme temperatures, and dry soils. In the desert, few plants and animals (and humans) are able to adapt to these harsh living conditions.
Deserts cover about a quarter of the Earth's surface, 53% of which correspond to hot deserts (such as the Sahara) and the rest to icy deserts (such as Antarctica)Deserts are found on five continents: the frozen plains of North Africa, northern Mexico, the Russian tundra, Antarctica, Greenland, and Alaska, as well as northern and southern Chile. An example of how these ecosystems can be affected by climate is the Atacama Desert, which can occasionally appear in bloom. You can also read about the desert turning green due to climate change.
In hot deserts, wind erosion and solar radiation are very intense, temperatures are high, and soils are often sandy, stony, or rocky. On the other hand, in the polar deserts, the temperature is usually below 0°C, the climate is dry and there is little flora and fauna.
desert features
Some of the main characteristics of deserts are:
- Little rainfall and dry weather. Deserts are areas that receive very little rain because they are areas where clouds do not form. For an area to be a desert, it must receive less than 250 mm of rainfall per year, and a lack of rainfall can lead to soil drought and biological scarcity. The rainfall that deserts can receive is usually sporadic and abundant, which causes erosion of the land due to the lack of vegetation that absorbs water.
- Dry ground. The lack of precipitation produces dry and parched soils. These soils are poor in nutrients and generally consist of sand or stones. In the case of polar deserts, the ground is covered by a large layer of ice.
- Extreme temperaturesIn the desert, temperatures are extreme, both hot and cold (as the case may be). In polar deserts, temperatures are typically below 0°C, while in hot deserts, temperatures are often above 40°C, and solar radiation is very strong. In most deserts, there is a large temperature difference between day and night. The fact that temperatures change so drastically between day and night is critical to understanding desert climate.
- The number of plants and animals is lowLack of rainfall and soil nutrients are some of the reasons that make it difficult for organisms to grow and develop in deserts. Most desert-dwelling species use mechanisms to store water or escape extreme temperatures. This makes desert fauna and flora very unique and adapted to extreme conditions, leading some animals to develop unique methods for survival.
- Erosion and low nutrient soilsWinds in desert areas are often strong and persistent, causing soil erosion due to the lack of vegetation. Furthermore, erosion, along with low rainfall, can lead to a reduction in soil nutrients, preventing the continued or altered growth of plant organisms. This results in an environment that is often difficult to inhabit.
types of deserts
The main types of deserts are:
- tropical desert: They are deserts located near the equator or the tropics. They are characterized by high temperatures, large thermal amplitudes during the day and night, and low precipitation and humidity. An example of such a desert is the Sahara desert in North Africa.
- polar desert: They are those deserts with very intense low temperatures, very dry, low solar radiation and little annual precipitation. Due to its harsh climate, there are few species of organisms that inhabit this biome. The Arctic Circle and Antarctica are regions of the planet's polar deserts.
- coastal desertThese are deserts located near the coast and the Tropic of Cancer and Capricorn. Despite being close to water, they are arid areas with very little rainfall, as the wind causes the rain to fall into the sea and the moisture never reaches the coast. An example of such a desert is the Atacama Desert in Chile, which sometimes appears in bloom.
- Semi-arid desert. They are those deserts with very little humidity, but more precipitation than tropical deserts. They are characterized by hot, dry summers and cold winters with little rainfall. An example of such a desert is the forest desert in Russia.
Desert climate
Temperatures in deserts are often extreme, with large temperature differences between day and night. In the hot desert temperatures exceed 40°C during the day and drop below freezing at night.
For its part, in the polar deserts, temperatures are always very low (about -40°C) and can exceed 0°C in summer. There are three types of desert climates based on mean annual precipitation:
- Semi-arid climate (steppe). They receive an average of 250 to 500 mm of rain per year, covering 15% of the earth's surface. They are usually found on the outer edge of the desert.
- Dry weather. Its annual rainfall ranges between 25 and 250 mm (maximum), covering 16% of the Earth's surface. This makes it one of the harshest climates.
- Super arid climate. They have very low rainfall rates, often experiencing years without rain in these areas. This climate exists in the heart of polar deserts and hot deserts. The most extreme deserts, such as the Atacama Desert, exemplify this category.
Flora and fauna
The desert flora is very specific and often scarce, due to low humidity, and many plants are unable to carry out photosynthesis. The flora of the deserts varies according to the type of climate.
In hot deserts, life has adapted to unfavorable conditions, which is why there is usually xerophytic vegetation: thorny, succulent, resistant plants with a great capacity for storing water. Some examples of desert heat flora are: cacti, agave, acacia, roses of Jericho, cacti and succulents. The adaptation of these plants is key to their survival and the stability of the ecosystem.
In hot deserts, there are areas with water (called oases) and humid conditions that encourage plants to bloom. An oasis is home to palm trees and taller shrubs, including fruit trees such as dates or coconut palms.
In the polar deserts, on the other hand, there is very little vegetation due to the lack of precipitation and the cold and permafrost. The flora of the arctic deserts is more abundant than that of Antarctica (only Antarctic grasses, Antarctic carnations and moss), inhabited by plants such as mosses, herbs, meadows and shrubs.
Living animals that are adapted to their desert environment and have mechanisms to keep their bodies hydrated. Some individuals hide in burrows to avoid the sun during the day, and some have water reserves in their bodies or physical characteristics that can help them cope with extreme temperatures and dehydration. In this sense, there are many animals of the sahara desert who have developed unique survival strategies, as well as you can learn about the Arabian Desert.
The frozen deserts, on the other hand, they do not have so many living beings, and the life of algae and bacteria stand out. However, the polar deserts of the Arctic have more animal species than Antarctica, and in the outermost areas of the desert it is possible to find bears, reindeer, foxes, hares and other mammals, which have insulating fur and store a lot of fat. Seals, killer whales, whales, fish, and plankton live in coastal areas and oceans.
In Antarctica, birds such as penguins, gulls, albatrosses, terns, and Antarctic petrels stand out, although most live near the coast (seals and marine animals can also be seen).
