Rewarding Deserts Trivia Quiz

Answer: Antarctica

A desert is usually defined by the amount of rainfall falling annually. Generally deserts will receive less than 250 mm of annual precipitation. Antarctica makes the grade as precipitation around the coast is around 200 mm per annum, with much less falling in the interior.

The Sahara, second largest of the world's deserts, covers an area amounting to about two-thirds of Antarctica's 14 million square kilometres. The Gobi and Kalahari Deserts are fourth and fifth largest respectively, both less than a tenth of Antarctica's size.

Answer: Katabatic winds

Low amounts of snowfall and low humidity mean that there is little water in the area to begin with. If snow were to fall, it is evaporated by the katabatic winds. Dense cold air flows from the surrounding mountains into the valleys. Gravity-driven, the winds can reach speeds of up to 320 km/h and, in the process, heat up and evaporate any snow or ice.

Answer: Salinity

With a significantly higher salinity level than the Dead Sea, Don Juan Pond is believed to be the saltiest body of water in the world. The salinity level is over 40%. Discovered in 1961, it was recorded as being 62 acres in size in 1977. In recent times it has shrunk to a few puddles.

Answer: Wind

This has been observed where wind blows over the top of sand dunes causing sand avalanches. The mechanism is not completely understood however conditions required include round grains of sand of a certain size and humidity, and containing silica. A low, rumbling sound is typical with the conditions perhaps allowing resonance to amplify the sound. On some beaches people can generate squeaking sounds when walking on the sand.

Answer: Adding minerals

Strangely, most of the mineral nutrients in these rainforests actually come from the Sahara in Africa, blown over the Atlantic in sand storms. Iron-poor areas of the oceans can get iron supplements from such storms. Loess, wind-deposited dust accumulations, have helped make areas of northern China and the American mid-west more fertile. Unfortunately, poor agricultural practices in modern times can result in such fertile soils disappearing.

The frequency of dust storms has increased dramatically in the last fifty years. There are now ten times as many in the Sahara than in the 1950s. Minerals are not the only thing sometimes transported. Such storms have also been known as a disease vector, transporting virus spores into the atmosphere.

Answer: Fog catchers

A Canadian experiment with canvas sheets in the 1980s led eventually to a scheme to use collectors to provide irrigation for reforestation attempts on El Tofo Mountain in Chile. This in turn prompted the nearby village of Chungungo to ask for water from the collectors to be piped to them. This was done and, using nylon mesh collectors, an average of 15,000 litres a day was being collected in 1992.

Ten years later, things were not so rosy. Various reasons seem to have contributed to this. The population had tripled because of the water now available however maintenance funds proved hard to obtain. A scheme to collect your own water was not, it seems, prestigious and the village pushed for a million dollar pipeline to collect water from a river some twenty miles away. Instead water was delivered by truck.

Answer: Ice-supported stones moved by light winds

Attracting attention since 1900, it was not until 2014 that the rocks were observed moving. It can take several years before conditions are right. In the winter, rainfall comes off the surrounding hills, flooding onto the dry lake, softening the mud and freezing to form thin ice sheets.

When the ice sheet starts to break up, the now more buoyant ice-collared rocks become mobile with light winds. They have been recorded with GPS and time-lapse photography moving at a rate of five metres per minute and over 200 metres in a season.

Answer: Sahara

The aquifer provides fossil water or paleowater. This is water that has been sealed underground for some time, perhaps millions of years. In the case of NSAS, it was 'charged' during the last ice age. It is non-renewable. The NSAS extends to some two million square kilometres and under four countries, including Libya.

Oil exploration in Libya during 1953 led to the discovery of the aquifer. Libya has since constructed the Great Man-made River project, which is claimed to be the world's largest irrigation system. Extracting water from some 1,300 wells, it could potentially last 1,000 years. Other estimates put this at as little as 60 years. One claim made is that fossil water extraction around the world has been responsible for a quarter of sea-level rise since the beginning of the 20th century.

The photo shows a dromedary camel which is the only type of camel found wild in Africa. The other deserts are found in Australia (Great Victoria Desert), North America (Chihuahuan Desert) and Asia (Gobi Desert).

Answer: Human activity

Deforestation, over-grazing of livestock, widespread pollution damaging productive soils, over-irrigation leading to salinisation of the soil, and depletion of water resources are all human-related activities which have changed the dynamics around the desert margins, helping desertification to take place.

Relocating hundreds of thousands of nomadic grazers, introducing land reclamation restrictions and water use restrictions have been carried with little effect. The Three-North Shelter Forest Program (also known as the Green Great Wall of China) is the flagship programme, a scheme to plant nine million acres of forestry windbreaks extending some 4,500 kilometres. It is not without its problems.

Planting has caused reductions in groundwater levels; monoculture plantations are not attractive to native flora and fauna and so has reduced biodiversity; and vast tracts of a single tree species are more susceptible to disease, leading for example, to the death of a billion poplar trees in 2000, setting the programme back by 20 years.

Answer: Astronomers

There are a number of observatories in this area which benefit from the lack of light and radio pollution, the clear night skies and the lack of moisture. The dry atmosphere is crucial as water vapour absorbs and attenuates millimetre and sub-millimetre radiation.

The Llano de Chajnantor Observatory at an altitude of 5,000m in the Antofagasta region, hosts a number of astronomy projects including the Atacama Large Millimeter Array (ALMA). This consists of 66 12-metre and 7-metre radio telescopes in an array. Over a billion dollars was allocated for this project.