DESERTS

Jeremy the Geographer

Biomes of the World: DESERTS

• Deserts cover about one-fifth of the Earth. It is usually an uninhabited land or a waterless and treeless region. Precipitation is less than 10 inches per year

• There are hot and cold deserts – HOT: Precipitation (rain) occurs less than ten inches

per year. – COLD: Precipitation (snow) occurs less than ten

inches per year.

Deserts Around the World

• Deserts can be found in: – Sahara of North Africa and the deserts of the

southwestern U.S., Mexico, and Australia at low latitudes (hot)

– Cold deserts, occur in the basin and range area of Utah and Nevada and in parts of Western Asia

Map of Desert Biomes

Physical Landscape of Deserts

• Deserts are a temperate or tropical biome,

• Commonly occurring in the center of continents and in the rain shadows of mountains. The distribution of deserts is determined by the availability of water (occur where less than 10 inches of rain)

• The ecosystems are strongly influenced by the availability of water. Very dry deserts have almost no plant life , while less-dry environments may support more plant life. Moister places will allow a shrub-dominated ecosystem to develop.

Types of Desert Biomes• Hot and Dry Deserts Examples: Like Sonoran Desert of Arizona and northwestern

Mexico are warm year-round with an extreme range of daily temperatures because of low humidity. Brief but heavy storms may occur . Soil is hard and rocky. Includes: The Great Sandy Desert of Australia and the Sahara of north Africa

• Semi-arid Deserts Examples: Like The Great Basin of Nevada and western Utah, have long dry summers plus winter rainfall. Dew fall may exceed rainfall. Soil is sandy and rocky.

• Cold Desert Examples: Like Greenland, have long cold winters and brief, barely warm summers. Soils are infertile, salty, alluvial silt. High cold deserts in Utah support a variety of burrowing mammals, coyotes, lizards and foxes. The Gobi in northern China and southern Mongolia falls under this category.

• Coastal Deserts Examples: Like Pacific coast of Baja California, have brief cool seasons and long summers. Rainfall may be as much as 13 cm a year. Coastal deserts support larger mammals such as coyotes, as well as amphibians, owls, eagles and reptiles.

Hot Deserts: Sahara of North Africa

• World’s largest, hottest desert• Total: 266,060 km²• land: 266,000 km² water: 0 km² Coastline: 1,110 km;• Land boundaries: 2,046 km• Sahara covers large parts of Algeria, Chad, Egypt, Libya,

Mali, Mauritania, Morocco, Niger, Western Sahara, Sudan and Tunisia.

• Nile River flows through• Sandy, windy desert, sand dunes shaped by wind • Main part is hyper-arid, with little vegetation.

Cold Deserts: The Great Basin

• Western United States (Idaho, Nevada, Oregon, and Utah) Covered by sand, gravel, and clay. Many mountains ranges, basins, and large expanses of salt flats.

• Water: Great Salt Lake (Utah), numerous lakes and creeks

• Highest Peak: Wheeler Peak (13,063 feet)• The Great Basin almost entirely contains the smaller

Great Basin physiographic section, which extends about 10,000 sq mi and covers the Colorado River

Coastal Deserts: Namib• Located on Coasts of Southwestern Africa, covered by sand dunes along

the coast and gravel farther inland.

• Coast of the Namib Desert is world's greatest source of gemstones.

• The Namib Desert is one of the 500 distinct physiographic provinces of the South African Platform physiographic division. It occupies an area of around 80,900 km²[2] (31,200 square miles), stretching from the Usiab River (north) to the town of Luderitz (south) and from the Atlantic Ocean (west) to the Namib Escarpment (east). It's long about 1,000 miles (1600 km) north-south and its east-west width varies from 30 to 100 miles (50-160 km)

• The Namib Desert is a desert in Namibia and southwest Angola that forms part of the Namib-Naukluft National Park, the largest game reserve in Africa.

Man’s Influence on Deserts• Global warming may affect climate change of deserts

• Human’s land exploitation resulting in the drainage of underground aquifers and soil poisoning through salinisation (salt) - is accelerating the rate at which deserts are drying out to the point of being killed off.

• Primary man-made cause of salinization is irrigation. River water or groundwater used in irrigation contains salts, which remain behind in the soil after the water has evaporated.

Sahara Desert

• Sand Dunes

• Dunes

Great Basin Deserts

Camp Grounds• Wheeler Peak

• Wheeler Lake

Namib Desert

Moon Valley

Bibliography

• http://www.natureali.org/great_basin_desert.htm

• http://www.independent.co.uk/environment/desert-life

• http://www.indianchild.com/deserts_of_the_world.htm

• http://www.ehow.com/facts_5132173_four-main-types-deserts.html

• http://en.wikipedia.org/wiki/Sahara