Hot Deserts Flashcards
(34 cards)
What are hot deserts like?
A desert is an area that receives less than 250mm of rainfall per year. The soils are infertile, and the biggest hot desert is the Sahara, covering 11 countries, including Egypt and Mauritania.
Where are hot deserts found?
Hot deserts are found in the Tropic of Cancer and the Tropic of Capricorn, 20 - 30 ° north and south of the Equator. There are a few anomalies, however, such as the Gobi Desert.
What is the climate of the Sahara like?
Hot and dry. The temperatures range from 12 ° C in January to 35 ° C in July, however, during the day temperatures can reach 40 ° C, and during the night they can drop to 0 ° C. The maximum amount of rainfall is in December, with 4mm, and the lowest is shared between June, July and September, each with 0mm.
Why is the climate of the Sahara like it is?
The climate is due to the desert’s location in the Tropics. At these latitudes, air that has risen at the Equator descends, and this forms a persistent belt of high pressure, which means that there is no precipitation or cloud cover. The temperatures can be boiling during the day because of a lack of clouds to block the heat, and during the night, the temperature drops because there are no clouds to hold the heat in.
How have camels adapted to living in the hot desert?
They have large, flat feet to spread their weight on the sand. They have thick fur on top of their body for shade, and thin fur elsewhere for easy heat loss. They have a large surface area to volume ratio to maximise heat loss. They can go without water for a long time due to the fat stored in their humps. They can tolerate body temperatures of up to 42 ° C and have slit like nostrils and thick eyelashes to keep sand out.
How have kangaroos adapted to living in the hot desert?
The kangaroo has a strong tail, so it can keep its balance while running through the desert. It has efficient organs because its intestine reabsorbs water, ensuring none is wasted. They also have a wrist cooling system, where they spit on their wrists. The spit evaporates, which leads to heat leaving the blood, cooling the body. They also have long, thin feet, meaning they can hop across large distances efficiently.
How have cacti adapted to living in the hot desert?
They have spines instead of leaves, and this helps them because they act as protection for the cactus, and they are good at retaining water. These spines have a small surface are compared to leaves, meaning they lose less water through transpiration. They also have wide roots, meaning they can collect water from a wider area quickly.
How has the guanacos adapted to living in a hot desert?
The guanacos are South American camels. They have dust baths to cool them down. Moist air rolls over the ocean in the Atacama, and it lets a blanket of fog roll over the desert. Droplets catch on cactus spines, and the guanacos drink from there.
What role does the saguaro cactus play in a hot desert?
Its long body stores water, and there are many creatures which live in the shadows of the cactus for protection. These cacti store water, and slowly shrink as water is being used up. Animals drink the droplets caught on its spines.
How have other plants adapted to living in the hot desert?
The ocotillo has adapted by shedding its leaves during dry spells, and can grow them back for up to five days after receiving water. Phreatophytes have long taproot systems which reach down 7 - 10m. Xerophytes have seeds which can stay dormant for years, but grow quickly after receiving water.
What is the interdependence between the abiotic factors and non abiotic factors in a hot desert?
Water is very scarce (less than 4mm of rainfall each month), and this makes the soil very infertile. It also means that animals and plants don’t have enough to survive and grow. The climate is extremely hot (up to 40 ° C), and this means that the water dries up fast, and the soil cracks up also. The animals and plants also have to adapt to living in a harsh environment. The plants affect the animals because they are their food, and they affect the water by trying to absorb as much of it as they can through long taproot systems that can stretch 7 - 10m underground. The animals affect the plants because many form symbiotic relationships, and they have also specially adapted to help them cope with body temperatures of 42 ° C.
What is the soil like in a hot desert?
The soil is shallow, and is coarse and gravelly. There is no leaf litter because there are not many plants, and it is very infertile. It is also very salty where water that has been there has evaporated. It is washed and blown away easily, and plants struggle to grow here. The O - Horizon is very thin, and there are not many nutrients, like calcium in the soil.
What is the biodiversity like in a hot desert?
Around 1,500 species live in hot deserts. Deserts cover around 25% of the Earth’s surface. Animals that have adapted to living in the desert are xerocoles, and they include camels, scorpions, beetles, roadrunners, hawks, tortoises, rodents, rabbits, coyotes and reptiles.
What are the challenges facing people in a hot desert?
There is not much water, or food in a desert. The sand is hot because of the weather, meaning it is hard to move across without burning their feet. A sandstorm can be 1,000 miles across, and there would be no way for a human to survive. There is also a lack of shelter, as materials are scarce.
How have humans adapted to cope with living in the hot desert?
300 million people survive in the desert. They have a nomadic lifestyle, which means they move around to find food and water. They have knowledge of where water will be and know what to do when they come across wild animals. They take risks to get water. Tribes in the Atacama use nets made out of cloth to catch and condense the water that comes from the Atlantic Ocean, and can get up to 500 litres of water a day from this. They also use underground aquifers to get water.
Why is oil and gas a development opportunity in the Sahara Desert?
There are believed to be large oil and gas reserves underneath the Sahara. For Algeria, oil is important, as it makes up 50% of the country’s economy. However, drilling for oil isn’t easy. Transport is limited, and the 40,000 workers at the Hassi Messaoud plant have to be flown in, and have their water pumped from underground.
Why is tourism a development opportunity in the Sahara Desert?
Many people are fascinated by remote and exotic desert locations. Marrakech had 10 million visitors in 2013, and activities include camel treks. However, due to climate change, water availability in Morocco has dropped from 1,000 metres cubed in 2000, and will drop to 490 metres cubed in 2020. This is below the UN’s “Absolute Water Scarcity Level”. Also, the temperatures of above 40° C mean that jobs are seasonal and people can get heatstroke.
Why is solar power a development opportunity in the Sahara Desert?
12 or more hours of bright sunshine and skies everyday are ideal for generating solar power. Tunisia plans to supply more than 2 million homes in Western Europe with electricity by 2018. However, high voltage electricity lines can cost millions of dollars per mile. Solar power plants also need a water source to cool the equipment, and there is not much water as it is in the desert. Dust is also a big problem, as mirrors have to be cleaned daily. One speck of dust isn’t transparent and reduces efficiency greatly.
Why is irrigation a development opportunity in the Sahara Desert?
The Egyptian government has been working on the Toshka Project, a $70 billion development which aims to increase Egypt’s irrigated land area by 30%. However, the project will have to completely rely on piped water as rainfall is unpredictable and rivers only flow for part of the year. The water used for irrigation contains a lot of mineral salts, and when this evaporates, salt is left behind. This can kill crops.
Why is mining for metallic minerals a development opportunity in the Sahara Desert?
Metallic minerals are of considerable economic importance. Algeria possesses several major deposits of iron ore, and the reserves in Mauritiana are substantial. However, access is a major issue. The Mauritiana Railway is 704km long and transports materials from the mining town of Zouerate to the coastal port of Nouadhibou. Also, leachate (water which has trickled through mining waste) can contaminate the water available.
What is desertification?
Desertification is the process by which fertile land becomes a desert, typically as a result of drought, deforestation, or inappropriate agriculture.
Why is removal of trees for fuelwood a cause of desertification?
When the trees are removed, large areas are left open to soil erosion, especially during periods of strong winds and rainstorms.
Why is overgrazing a cause of desertification?
Overgrazing is where too many animals are farmed in too small an area, which leads to the soil becoming compacted by the hooves of cattle. This means that the soil eventually becomes unable to sustain plant life.
Why is overcultivation a cause of desertification?
This is where more people demand food, and too many crops are grown. This leads to deterioration of the soil quality.
