Difference between revisions of "Namib Desert" - New World Encyclopedia

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[[Image:Dune_7_in_the_Namib_Desert.jpeg|250px|thumb|Dune 7, the highest sand dune in the world (ca. 383 m.), in the Namib Desert, Namibia.]]
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[[Image:NamibDesert01.jpg|250px|thumb|Sunset at the Namib Rand Nature Reserve, Namibia]]
[[Image:ConceptionBay Namibia ISS011-E-9756.jpg|thumb|250px|The dune sea of the Namib Desert. Note how the crests of the dunes are aligned in a marked northwest-southeast orientation. These crests form transverse to the formative wind (i.e. crosswise). The dunes act as obstacles, and obstacles cause winds to be deflected significantly to the right, in the southern hemisphere—in effect reorienting the southerly wind as a southwesterly wind.]]
 
[[Image:NamibDesert01.jpg|250px|thumb|Sunset at the [[Namib Rand Nature Reserve]], Namibia.]]
 
  
The '''Namib Desert''' is a [[desert]] in [[Namibia]] which forms part of the Namib-Naukluft National Park, one of Africa's largest. The name "Namib" is from a word in the Nama language that means "immense." The desert occupies an area of around 1 E10 |50 000 km², stretching some 1,000 miles (1,600 km) along the [[Atlantic Ocean]] coast of Namibia, which is named after this desert. Its east-west width varies from 30 to 100 miles (50-160 km). The Namib Desert also reaches into southwest [[Angola]].
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The '''Namib Desert''' is a coastal [[desert]] in [[Namibia]] and southwestern [[Angola]] that encompasses the world's highest [[sand dune]]s, [[gravel]] plains, and rugged [[mountain]]s. It stretches some 1,200 miles (1,900 km) along the [[Atlantic]] coast of Namibia, which is named after this desert. The name "Namib" is from a word in the Nama language that means "immense." The desert occupies an area of around 31,200 (80,000 km²), though its east–west width varies from 30 to 100 miles (50–160 km). The area is considered to be the oldest desert in the world, having endured arid or semi-arid conditions for an estimated 55 to 80 million years. The Namib is an important location for the mining of [[diamond]]s, [[tungsten]], and [[salt]]. The diamonds, which are alluvial, are found in beds of gravel.
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The desert's aridity is caused by the descent of dry, warm air from the east that is cooled by the cold Benguela current along the coast. The upper layer of warm, dry air prevents the cool, humid air from rising and forming clouds. Some areas have less than half an inch (10 mm) of [[rain]] annually and are almost completely barren.
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[[Image:Dune_7_in_the_Namib_Desert.jpeg|250px|thumb|Dune 7, the highest sand dune in the world (ca. 383 m.), in the Namib Desert, Namibia]]
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== History ==
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{{readout||left|250px|The Namib Desert, stretching 1,000 miles along the [[Atlantic]] coast of Southern Africa, is believed to be the world's oldest [[desert]] having been arid for at least 55 million years}}
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The Namib Desert is believed to be the world’s oldest [[desert]] and it has been arid for at least 55 million years. The convergence of the [[Benguela]] upwelling and the hot interior have maintained, and perhaps increased, this aridity in recent times, but they did not generate the aridity. The region, isolated between the [[ocean]] and the [[escarpment]], is considered to be a constant island of aridity surrounded by a sea of climatic change. The arid conditions probably started with the continental split of West [[Gondwana]] 130 million to 145 million years ago when this area shifted to its present position along the [[Tropic of Capricorn]]. This lengthy dry period has had a profound influence on the region’s [[biodiversity]]. The region has remained a relatively stable center for the [[evolution]] of desert [[species]]. This has resulted in a unique array of biodiversity with high levels of endemism and numerous advanced adaptations to arid conditions.<ref> [http://www.worldwildlife.org/wildworld/profiles/terrestrial/at/at1315_full.html Namib desert]. ''World Wildlife Fund.'' Retrieved March 23, 2007. </ref>
  
The area is considered to be the oldest desert in the world, having endured [[arid]] or semi-arid conditions for at least eighty million years. Its aridity is caused by the descent of dry air cooled by the cold Benguela current along the coast. It has less than 10&nbsp;mm (0.4 inches) of rain annually and is almost completely barren.  
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==Flora and fauna==
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[[Image:Springbok Antelope Namib Desert .jpg|270px|thumb|left| A springbok [[antelope]] in the Namib Desert]]
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The Namib Desert is home to a number of unusual [[species]] of [[plant]]s and [[animal]]s that are found nowhere else in the world. One of these is ''Welwitschia mirabilis,'' a [[shrub]]-like plant that grows just two long leaves continuously throughout its lifetime. These leaves may grow to be several meters long and over time become gnarled and twisted from the desert winds. They are the longest-lived leaves of any member of the plant kingdom. It is estimated that the largest of these plants are about 2,500 years old.  
  
A number of unusual [[species]] of [[plant]]s and [[animal]]s are found only in this desert.  One of these is ''Welwitschia mirabilis'', a shrublike plant but grows just two long, strap-shaped leaves continuously throughout its lifetime. These leaves may be several meters long, gnarled and twisted from the desert winds. The taproot of the plant develops into a flat, concave disc with age.  ''Welwitschia'' is notable for its survival in the extremely arid conditions in the Namib, sometimes deriving moisture from the coastal sea fogs. Cold water meeting the hot desert is what creates the fog along the coast. These fogs and the fresh water they contain are the life essence of the Namib. Moisture condenses on desert grasses and on the bodies of smaller creatures. These sparse drops of dew are what sustain many of these animals.Devoid of rivers, the desert offers only a sparse selection of muddy water holes, but the animals of the Namib are not particular. In the first hours of the day, before the heat sears the land, gemsbok, ostriches, sand grouse, vultures, and wart hogs congregate at these oases to drink.
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Dense fogs along the coast and the freshwater they contain are the life essence of the Namib. The dew that condenses on desert [[grasses]] and on the bodies of smaller creatures is what sustains many of these animals. Others take advantage of the few muddy water holes, which may draw [[Oryx|gemsbok]], [[ostrich]]es, [[sand grouse]], [[vulture]]s, and [[warthog]]s.
  
Also known as the oryx, the gemsbok has the lightest colored coat of any long-horned antelope subspecies and ventures the deepest into the desert. The gemsbok can withstand the intense heat of the Namib because of its intricate system of blood vessels and nasal passages, which cool blood before it reaches the brain.
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Most of the animals and plants that survive in the Namib do so by unique adaptations. The gemsbok, for example, also known as the oryx, has a lighter coat than any long-horned [[antelope]] subspecies and an intricate system of [[blood]] vessels and nasal passages that cool its blood before it reaches the [[brain]]. They dig for underground water, drink from watering holes, and feed in the early morning on plants with high moisture content. Its numerous adaptations allow it to tolerate high temperatures and go days without water.
Gemsbok obtain water by digging for it underground, drinking from watering holes, and feeding in the early morning on plants with high moisture content. Access to watering holes is determined by sex and physical condition, males evicting females and the strong evicting the weak. If no water is available, gemsbok will let their body temperature rise before they begin to sweat, and will also raise their respiration rate from 20 to 120 pants per minute. At night, in order to sustain their body temperature without losing any water, they will breath slowly and deeply. As result of the gemsbok's numerous adaptations, it is able to tolerate high temperatures and go days without water.
 
  
Heavy fishing off the Namib coast has led to a decline the fish population, and consequently, a drop in the region's seabird population. Still, at least 150 bird species persist in the area, including flamingos, pelicans, and terns.
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There are almost 70 [[reptile]] species in the ecoregion, of which five are found only in the Namib Desert. The desert is also home to a large number of small [[rodent]] species that occur among the rocky habitats in the western deserts, in the sand dunes, and in the vegetation of the gravel plains.
Jackass penguins, found nowhere else on Earth, inhabit several islands just off the Namib coast. Of the many bird species in Namib, perhaps none has been as dramatically detrimented by commerical fishing as the jackass penguin. The population has dropped nearly 90% since 1930, when it numbered over 1,000,000.
 
  
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Namib-Naukluft National Park, one of [[Africa]]'s largest, contains a group of huge [[sand dune]]s, which at nearly a thousand feet (300 meters) high are the tallest sand dunes in the world. During the rainy season in some years, the waters of the Tsauchab River form pools at the base of the dunes. Sossusvlei is a great dry clay marsh (“vlei”). “Sossus” means “blind river” in the Nama language, so the literal translation of the word Sossusvlei is “marsh of the blind river,” that is, “marsh of the river that does not have a mouth toward the sea.”
  
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The interaction between the water-laden air coming from the sea via southerly winds, some of the strongest of any coastal desert, and the dry air of the desert causes immense fogs and strong currents in which sailors easily lose their way. Along with the [[Skeleton Coast]] farther north, the area is notorious as the site of many shipwrecks. Some of these wrecked vessels can be found as much as 50 meters inland, as the desert is slowly creeping westward into the sea, reclaiming land over a period of many years.
  
Although the desert is largely unpopulated and inaccessible, there are year-round settlements at Sesriem, close to Sossusvlei and a huge group of [[sand dune]]s, which at up to 340 meters high are the tallest sand dunes in the world. The complexity and regularity of dune patterns in its dune sea have attracted the attention of [[geologist]]s for decades; however, they remain poorly understood.
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The border of the desert to the north and east is the foot of the Great Western Escarpment of [[Namibia]], atop which more humid lands prevail. But in the south, a gradual transition merges the Namib with the [[Karoo Desert|Karoo]] and [[Kalahari Desert|Kalahari]] deserts of the interior.
  
Sossusvlei is a great dry clay marsh (“vlei”). In some years, during the rainy season the waters of the Tsauchab River arrived around Sossusvlei, forming evocative pools of water at the feet of dunes. “Sossus” means “blind river” in the Nama language, so the literary translation of the word Sossusvlei is “marsh of the blind river”, that is “marsh of the river that does not have a mouth towards the sea”.
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A curious feature of the Namib Desert is circles on the ground that are accentuated by abrupt changes in the vegetation pattern. These circles, known as "fairy rings," are most noticeable from the air. There has been interest and speculation as to their origin for centuries. It is now thought that they are created by a [[termite]].
  
The interaction between the water-laden air coming from the sea via southerly [[wind]]s, some of the strongest of any coastal desert, and the dry air of the desert causes immense [[fog]]s and strong currents in which sailors easily lose their way. Along with the Skeleton Coast farther north, the area is notorious as the site of many shipwrecks. Some of these wrecked ships can be found as much as 50 meters inland, as the desert is slowly creeping westward into the sea, reclaiming land over a period of many years.
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==Climate==
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[[Image:ConceptionBay Namibia ISS011-E-9756.jpg|thumb|250px|The dune sea of the Namib Desert. The crests of the dunes are aligned in a marked northwest-southeast orientation. These crests form crosswise to the formative wind. The dunes act as obstacles, and obstacles cause winds to be deflected significantly to the right in the Southern Hemisphere—in effect reorienting the southerly wind as a southwesterly wind.]]
  
The Namib is an important location for the mining of [[tungsten]], [[salt]], and [[diamond]]s.
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Climatically, the Namib is a contradictory area: It is almost rainless, yet its air is normally at or near the saturation point, and fog is very common. Temperatures in the coastal area are mild at all seasons, ranging between 58° and 67° F  (14° to 20° C) in the warm season (December) and between 46° and 57° F (9° to 14° C) in the cool season (July). Inland, summer temperatures reach the 80s and even over 100° (30 to 45° C) during the day and drop into the low 40s (4 to 7° C) on the average winter night. On the coast, humidity is 100 percent for 19 hours per day in summer and for 11 hours in winter. At the inner edge of the desert, the air is much drier, fog is virtually unknown, and the humidity seldom exceeds 50 percent. This is nevertheless fairly high for a desert region. Violent weather is practically unknown; rare [[thunderstorm]]s bring the precipitation, which averages less than {{convert|2|in}} annually inland and about {{convert|0.5|in}} at the coast.
  
Access is via light aircraft from Windhoek (the capital of Namibia, about 480&nbsp;km east of the center of the desert), Swakopmund and Walvis Bay at the north end of the desert, or overland on gravel roads.  
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==Threats==
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A major threat to the Namib Desert is the impact of off-road driving, which is greatest on the gravel plains where depressions left by vehicles remain for more than forty years because the rainfall is too episodic and sparse to erase them. These tracks are unsightly and cause long-lasting damage to the lichen fields. [[Lichen]]s are particularly sensitive to mechanical damage as they grow extremely slowly and cannot quickly repair damaged thalli. Most of the damage is done by mining company vehicles on prospecting expeditions.
  
== References ==
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The major threat to Namib-Naukluft National Park is the drop in the water table along the Kuiseb River, caused primarily by the extraction of [[groundwater]], which supplies the domestic consumption of Walvis Bay and Swakopmund and the enormous demands made by a [[uranium]] [[Mining|mine]] near Swakopmund. At present, the Department of Water Affairs is trying to meet the requirements for water by prospecting for more underground water sources. If water were to be found, roads, pipelines, and power lines would have to be constructed through the most pristine dune desert in the world. The Kuiseb River and the vegetation within it act as a windbreak to the southerly winds, retarding the northward movement of the dune sea onto the gravel plains. The destruction of this natural barrier would have serious ecological consequences in this part of the Namib Desert. Another threat to the Namib-Naukluft Park is the [[Pastoralism|pastoralists]] who graze large herds of [[goat]]s and small groups of [[donkey]]s over the bed of the Kuiseb River and along the edge of the dunes. The livestock have overgrazed the understory plant growth and the fallen acacia seedpods in the riverbed and are competing for food with wild animals, such as gemsboks.
* ''National Geographic'', January 1992, pp. 54-85.
 
* {{cite web | url=http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17050 | title=Dune Patterns, Namib Desert, Namibia | publisher=[[NASA Earth Observatory]] | accessdate=2006-05-05}}
 
* [http://www.acrossthedivide.com/namib.htm  Namib Naukluft Park photo gallery]
 
* [http://www.travelsaround.eu/eng/namibia/namibdesert/index.html  Namib Desert photo gallery]
 
* [http://www.greatestplaces.org/notes/namib.htm], observed March 18, 2007.
 
{{Category:Deserts}}
 
[[Category:Ecoregions]]
 
[[Category:Nations and places]]
 
[[Category:Africa]]
 
{{Link FA|uk}}
 
  
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== Notes ==
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<references/>
  
{{credit|105519982}}
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== References ==
Its eastern border in the north and center is the foot of the Great Western Escarpment, atop which more humid lands prevail; but in the south, a gradual transition merges the Namib with the Kalahari and Karoo Deserts of the interior.  
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* Barnard, Phoebe. ''Biological Diversity in Namibia: A Country Study.'' Windhoek, Namibia: The Task Force, 1998. ISBN 0869764365
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* Bartlett, Des, and Jen Bartlett. “Africa’s Skeleton Coast.” ''National Geographic'' (January 1992): 54–85.
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* Lovegrove, Barry. ''The Living Deserts of Southern Africa.'' Vlaeberg: Fernwood Press, 1994. ISBN 978-0958315470
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* Kinahan, John. ''Pastoral Nomads of the Central Namib Desert: The People History Forgot.'' Windhoek: Namibia Archaeological Trust, 1991. ISBN 9789991631028
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* Keen, Cecil. [http://www.greatestplaces.org/notes/namib.htm Greatest Places Physical Geography: Namib] ''Science Museum of Minnesota,'' 1997. Retrieved March 18, 2007.
  
Climate: Climatically, the Namib is a contradictory area: It is almost rainless, yet its air is normally at or near the saturation point, and fog is very common. Temperatures in the coastal area are mild at all seasons, ranging between a maximum of 67 degrees Fahrenheit and a minimum of 58 degrees Fahrenheit in the warm season (December) and between 57 degrees Fahrenheit and 46 degrees Fahrenheit in the cool (July). Inland, more continental conditions prevail, with summer temperatures reaching the 80s each day and dropping into the low 40s on the average winter night on the coast, humidity is at 100 percent for 19 hours per day in summer and for 11 hours in winter. At the inner edge of the desert, the air is much drier, fog is virtually unknown, and the humidity seldom exceeds 50 percent. This is nevertheless fairly high for a desert region. Violent weather is practically unknown. rare thunderstorms bring the precipitation, which averages less than 2 inches annually inland, and about one-half inch at the coast. Strong winds blow a few days a year from the interior, bringing heat and discomfort to the coast. But storms such as characterize mid-latitude areas are totally unknown.
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==External links==
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All links retrieved November 10, 2022.
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* [http://www.namibian.org/travel/namibia/namib-naukluft.htm Namib Desert]
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* [http://www.pbs.org/edens/namib/ Namib - Africa's burning shore] ''PBS''
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* [http://www.pbs.org/wnet/nature/episodes/the-desert-lions/secrets-of-survival-life-in-the-namib-desert/687/ The Desert Lions, Secrets of Survival: Life in the Namib Desert] ''PBS''
  
Landforms: The Namib is characterized by several distinct types of landforms: A vast sand sea, monotonously flat plains of gravel and bedrock, mountains of bare rock, and areas with surfaces fretted into strange sandblasted forms. Most of the desert consists of a broad platform, eroded into bedrock of monotonous flatness and rising in a very gradual slope from the coastline to an elevation of some 3,000 feet at the foot of the escarpment. South of the Tropic (of Capricorn), much of this platform is veneered with sand, in the form of sheets, waves, and dunes, the latter sometimes exceeding 800 feet, making them the highest sand dunes in the world. In the southern and central portions, mountains rise about the smooth platform only as isolated individuals and short chains. Most of the mountains are rugged, steep sloped, and almost soilless.
 
  
Vegetation : In general, the Namib is a barren waste, with very sparse vegetation. Large areas, notably the gravel flats, the bedrock platform, and the dunes, are almost totally barren. In the zone of heaviest fog near the coast, especially in the south, low succulent bushes grow sporadically. Along the eastern border, a thin to moderate cover of annual grasses appears in most years, supporting for a time a variety of antelopes, zebra, ostrich, and their attendant predators.
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{{Category:Deserts}}
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{{credit|105519982}}
  
Water Supply : Potable water is found only as sub-flow beneath streambeds chiefly of the larger streams that rise in the rainier plateau east of the escarpment. In some cases, dissolved salts render the water unpleasant. In other cases, such as the Kuiseb and the Koichab, which supply Walvis Bay and Luderitz, the quality is good to excellent.
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[[Category:Geography]]
 
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[[Category:Africa]]
Settlements : Walvis Bay has the only harbor on the Namibian coast accessible to deep-water vessels with large freighters and tankers able to come alongside the modern, efficient wharves. Fishing factories line the shore of the bay, each with its own wharf. As the only deep-water railhead in the country, Walvis Bay serves as the principal entry port for the interior. In addition to fish products, exports are chiefly minerals, wool, hides, and pelts destined for all parts of the world. Imports consist chiefly of manufactured goods, petroleum, and foodstuffs. The total population of the town is about 21,000. The water supply to the town is via a pipeline from the Kuiseb River, 23 miles to the southeast, where it is tapped from wells into the underflow of the river. Luderitz is a small-scale replica of Walvis Bay, except that its harbor is not suitable for deep-water vessels. The town's chief role is as the base for the rock lobster or crayfish industry. As a cargo port, its role is minor; its hinterland is poor and is serviced by a rail line and a single graded road. Its population is about 10,000. Its water supply also is from an underflow well mining (of the Koichab River through a 67-mile pipeline across the Namib.
 
 
 
Mining : Diamonds constitute by far the most important mineral product in the territory. The diamonds are alluvial, being found in beds of gravel, usually under a considerable overburden of sterile materials. The large-scale operation of recovery of diamonds is now under one corporation: the Consolidated Diamond Mines (CDM). Because of the high value and light weight of the product and the resultant ease of theft (combined with the difficulty of rescue operations for retrieving "poachers" stranded in this extremely arid region), the entire diamond bearing area and much of its surroundings has been proclaimed a Prohibited Area (Sperrgebiet), totally closed to public entry at all times. The CDM company town of Oranjemund, at the mouth of the Orange River, is the center of diamond mining operations. It is a highly developed, progressive, modern community, with a good water supply from wells near the river and with gardens supplying fresh produce. Offshore dredging operations for the recovery of diamonds from the sea bed have been carried on.
 
 
 
Other minerals mined in the Namib include zinc (Rosh Pinah mine), tin and wolfram (at Uis and Brandberg Wes). Oil prospecting has been carried out in recent years, but without success.
 
 
 
Recreation and Tourism : Since the time of German Southwest Africa, the coastal towns of the Namib have always had an attraction to the few and hardy. With the cooler summer climate, the fishing, the relative barrenness of the area, and its historic Germanic flavor have all been attractions for visitors.
 

Latest revision as of 01:13, 11 November 2022

Sunset at the Namib Rand Nature Reserve, Namibia

The Namib Desert is a coastal desert in Namibia and southwestern Angola that encompasses the world's highest sand dunes, gravel plains, and rugged mountains. It stretches some 1,200 miles (1,900 km) along the Atlantic coast of Namibia, which is named after this desert. The name "Namib" is from a word in the Nama language that means "immense." The desert occupies an area of around 31,200 m² (80,000 km²), though its east–west width varies from 30 to 100 miles (50–160 km). The area is considered to be the oldest desert in the world, having endured arid or semi-arid conditions for an estimated 55 to 80 million years. The Namib is an important location for the mining of diamonds, tungsten, and salt. The diamonds, which are alluvial, are found in beds of gravel.

The desert's aridity is caused by the descent of dry, warm air from the east that is cooled by the cold Benguela current along the coast. The upper layer of warm, dry air prevents the cool, humid air from rising and forming clouds. Some areas have less than half an inch (10 mm) of rain annually and are almost completely barren.

Dune 7, the highest sand dune in the world (ca. 383 m.), in the Namib Desert, Namibia

History

Did you know?
The Namib Desert, stretching 1,000 miles along the Atlantic coast of Southern Africa, is believed to be the world's oldest desert having been arid for at least 55 million years

The Namib Desert is believed to be the world’s oldest desert and it has been arid for at least 55 million years. The convergence of the Benguela upwelling and the hot interior have maintained, and perhaps increased, this aridity in recent times, but they did not generate the aridity. The region, isolated between the ocean and the escarpment, is considered to be a constant island of aridity surrounded by a sea of climatic change. The arid conditions probably started with the continental split of West Gondwana 130 million to 145 million years ago when this area shifted to its present position along the Tropic of Capricorn. This lengthy dry period has had a profound influence on the region’s biodiversity. The region has remained a relatively stable center for the evolution of desert species. This has resulted in a unique array of biodiversity with high levels of endemism and numerous advanced adaptations to arid conditions.[1]

Flora and fauna

A springbok antelope in the Namib Desert

The Namib Desert is home to a number of unusual species of plants and animals that are found nowhere else in the world. One of these is Welwitschia mirabilis, a shrub-like plant that grows just two long leaves continuously throughout its lifetime. These leaves may grow to be several meters long and over time become gnarled and twisted from the desert winds. They are the longest-lived leaves of any member of the plant kingdom. It is estimated that the largest of these plants are about 2,500 years old.

Dense fogs along the coast and the freshwater they contain are the life essence of the Namib. The dew that condenses on desert grasses and on the bodies of smaller creatures is what sustains many of these animals. Others take advantage of the few muddy water holes, which may draw gemsbok, ostriches, sand grouse, vultures, and warthogs.

Most of the animals and plants that survive in the Namib do so by unique adaptations. The gemsbok, for example, also known as the oryx, has a lighter coat than any long-horned antelope subspecies and an intricate system of blood vessels and nasal passages that cool its blood before it reaches the brain. They dig for underground water, drink from watering holes, and feed in the early morning on plants with high moisture content. Its numerous adaptations allow it to tolerate high temperatures and go days without water.

There are almost 70 reptile species in the ecoregion, of which five are found only in the Namib Desert. The desert is also home to a large number of small rodent species that occur among the rocky habitats in the western deserts, in the sand dunes, and in the vegetation of the gravel plains.

Namib-Naukluft National Park, one of Africa's largest, contains a group of huge sand dunes, which at nearly a thousand feet (300 meters) high are the tallest sand dunes in the world. During the rainy season in some years, the waters of the Tsauchab River form pools at the base of the dunes. Sossusvlei is a great dry clay marsh (“vlei”). “Sossus” means “blind river” in the Nama language, so the literal translation of the word Sossusvlei is “marsh of the blind river,” that is, “marsh of the river that does not have a mouth toward the sea.”

The interaction between the water-laden air coming from the sea via southerly winds, some of the strongest of any coastal desert, and the dry air of the desert causes immense fogs and strong currents in which sailors easily lose their way. Along with the Skeleton Coast farther north, the area is notorious as the site of many shipwrecks. Some of these wrecked vessels can be found as much as 50 meters inland, as the desert is slowly creeping westward into the sea, reclaiming land over a period of many years.

The border of the desert to the north and east is the foot of the Great Western Escarpment of Namibia, atop which more humid lands prevail. But in the south, a gradual transition merges the Namib with the Karoo and Kalahari deserts of the interior.

A curious feature of the Namib Desert is circles on the ground that are accentuated by abrupt changes in the vegetation pattern. These circles, known as "fairy rings," are most noticeable from the air. There has been interest and speculation as to their origin for centuries. It is now thought that they are created by a termite.

Climate

The dune sea of the Namib Desert. The crests of the dunes are aligned in a marked northwest-southeast orientation. These crests form crosswise to the formative wind. The dunes act as obstacles, and obstacles cause winds to be deflected significantly to the right in the Southern Hemisphere—in effect reorienting the southerly wind as a southwesterly wind.

Climatically, the Namib is a contradictory area: It is almost rainless, yet its air is normally at or near the saturation point, and fog is very common. Temperatures in the coastal area are mild at all seasons, ranging between 58° and 67° F (14° to 20° C) in the warm season (December) and between 46° and 57° F (9° to 14° C) in the cool season (July). Inland, summer temperatures reach the 80s and even over 100° (30 to 45° C) during the day and drop into the low 40s (4 to 7° C) on the average winter night. On the coast, humidity is 100 percent for 19 hours per day in summer and for 11 hours in winter. At the inner edge of the desert, the air is much drier, fog is virtually unknown, and the humidity seldom exceeds 50 percent. This is nevertheless fairly high for a desert region. Violent weather is practically unknown; rare thunderstorms bring the precipitation, which averages less than 2 inches (51 mm) annually inland and about 0.5 inches (13 mm) at the coast.

Threats

A major threat to the Namib Desert is the impact of off-road driving, which is greatest on the gravel plains where depressions left by vehicles remain for more than forty years because the rainfall is too episodic and sparse to erase them. These tracks are unsightly and cause long-lasting damage to the lichen fields. Lichens are particularly sensitive to mechanical damage as they grow extremely slowly and cannot quickly repair damaged thalli. Most of the damage is done by mining company vehicles on prospecting expeditions.

The major threat to Namib-Naukluft National Park is the drop in the water table along the Kuiseb River, caused primarily by the extraction of groundwater, which supplies the domestic consumption of Walvis Bay and Swakopmund and the enormous demands made by a uranium mine near Swakopmund. At present, the Department of Water Affairs is trying to meet the requirements for water by prospecting for more underground water sources. If water were to be found, roads, pipelines, and power lines would have to be constructed through the most pristine dune desert in the world. The Kuiseb River and the vegetation within it act as a windbreak to the southerly winds, retarding the northward movement of the dune sea onto the gravel plains. The destruction of this natural barrier would have serious ecological consequences in this part of the Namib Desert. Another threat to the Namib-Naukluft Park is the pastoralists who graze large herds of goats and small groups of donkeys over the bed of the Kuiseb River and along the edge of the dunes. The livestock have overgrazed the understory plant growth and the fallen acacia seedpods in the riverbed and are competing for food with wild animals, such as gemsboks.

Notes

  1. Namib desert. World Wildlife Fund. Retrieved March 23, 2007.

References
ISBN links support NWE through referral fees

  • Barnard, Phoebe. Biological Diversity in Namibia: A Country Study. Windhoek, Namibia: The Task Force, 1998. ISBN 0869764365
  • Bartlett, Des, and Jen Bartlett. “Africa’s Skeleton Coast.” National Geographic (January 1992): 54–85.
  • Lovegrove, Barry. The Living Deserts of Southern Africa. Vlaeberg: Fernwood Press, 1994. ISBN 978-0958315470
  • Kinahan, John. Pastoral Nomads of the Central Namib Desert: The People History Forgot. Windhoek: Namibia Archaeological Trust, 1991. ISBN 9789991631028
  • Keen, Cecil. Greatest Places Physical Geography: Namib Science Museum of Minnesota, 1997. Retrieved March 18, 2007.

External links

All links retrieved November 10, 2022.



Deserts
Ad-Dahna | Alvord | Arabian | Aral Karakum | Atacama | Baja California | Barsuki | Betpak-Dala | Chalbi | Chihuahuan | Dasht-e Kavir | Dasht-e Lut | Dasht-e Margoh | Dasht-e Naomid | Gibson | Gobi | Great Basin | Great Sandy Desert | Great Victoria Desert | Kalahari | Karakum | Kyzylkum | Little Sandy Desert | Mojave | Namib | Nefud | Negev | Nubian | Ordos | Owyhee | Qaidam | Registan | Rub' al Khali | Ryn-Peski | Sahara | Saryesik-Atyrau | Sechura | Simpson | Sonoran | Strzelecki | Syrian | Taklamakan | Tanami | Thar | Tihamah | Ustyurt

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