Atacama Desert

Atacama Desert

The Atacama Desert of Chile covers the northern third of the country stretching 1,000km (600 miles) and straddles the southern border of Peru. Bound on the west by barren hills and mountains on the Pacific coast it extends east into the Andes mountains. At an average elevation of about 4 kilometers (13,000 feet) it is not only the highest desert in the world but also the driest. In some parts rainfall has never been recorded. Vegetation is almost non-existent with 0.6mm to 2.1mm of rain falling around the region. Average daily temperatures range between 0°C-25°C making the Atacama relatively cool compared with the Sahara or the Great Sandy desert's.

Despite extremes and desolation there is stunning beauty. With the Andes as a backdrop the desert contains five snow topped volcanoes which are the highest volcanoes in the world and the highest elevations in South America.

Geography

Scene from Valle de la Luna (Moon Valley) near San Pedro de Atacama.

Sparsely populated and virtually rainless, the Atacama Desert forms a narrow strip on the coast of Chile, between 600 — 700 miles long. The average with, from the Pacific Ocean on the east to the Andes Mountains on the west, is less than 60 miles (100 km). The north end of the desert lies at border of Chile, while the south stretches to the bend of the Loa River and the mountains separating the Salado-Copiapó drainage basins.

The average rainfall in the desert ranges from 0.6 mm (in Arica) to 2.1 (in Iquique). However, there are some areas which have never recorded rainfall. Dr. Tibor Dunai who spoke before the American Geophysical Union told the BBC in a news article: "We found loose sediment surfaces that would be washed away by any desert rainfall and these are older than 20 million years," he said. This is much older than other hyper-arid regions, such as the Dry Valleys of Antarctica (10-11 million years) and the Namib Desert in Africa (5 million years). "The origin of the aridity in the Atacama dates back to the opening of ocean pathways - the opening between South America and Antarctica, and between Australia and the Antarctic.

What is known as fog-zone plant communities have developed due to the entrapment of clouds by mountains or steep coastal slopes. These communities lie near the coast and in lower portions of numerous gorges between sea level and 1,100 m. Short-lived perennial and woody scrub vegetation grow here.

Other areas receive marine fog, providing sufficient moisture for hypolithic algae, lichens and even some cacti. In these areas, even decomposition does not occur. Dead vegetation may be thousands of years old. A recent innovation has made it possible to catch water from the air. With the use of mesh nets, water is trapped and trickled off via piping into storage tanks.

In the southern desert, fog-zone vegetation supports approximately 230 species of vascular plants. Included are the dominant species of Euphorbia lactiflua and Eulychnia iquiquensis. Other shrubby species in the zone include Echinopsis coquimbana, Oxalis gigantea, Lycium stenophyllum, Proustia cuneifolia, Croton chilensis, Balbisia penduncularis and Tillandsia geissei. Bromeliads are also present along the coastal flats in this southern part, and include Deuterocohni chrysantha and Puya boliviensis.

Astrobiologists are studying the Atacama to discover clues which may unlock secrets of life on other planets and the possibility of survival there. They are also studying the growth of plants in extreme places in order to develop plants that could be grown off—world or on Mars.

Biodiversity

The plant and animal life in the Atacama survive in perhaps the earth's most demanding conditions. There is a high incidence of endemic flora. Local populations have relied on some of the species for medicinal purposes for generations.

Approximately 550 species if vascular plants have been discovered in the Atacama, the most diverse being the families of Asteraceae, Nolanaceae, Cataceae, Boraginaceae, and Apiaceae. Three cacti are endemic to the northern part of the Atacama Desert; they are Eulychnia iquiquensis, Neoporteria sensu and Copiapoa. There are also numerous endemic shrubs.

Animal life is very rare in this desert, though there are a few insects and lizards to be found. Mice and fox are there in small number.

The fog-zone plant communities, or lomas, provide a friendlier environment. Birds such as the Peruvian song-sparrow, Pacific blue-black grassquit and hummingbirds live there, for at least a portion of the year. Six restricted species can be found in the north region: thick-billed miner, white-throated earthcreeper, cactus canastero, Chilean woodstar, slender-billed finch and the tamarugo conebill, the latter three of which are considered threatened species.

Resources

The area proved to be one of the chief sources of Chile's wealth until World War I. Nitrate deposits in the central depression and in several basins of the coastal range were systematically mined after the mid-19th century. Ports were built at Iquique, Caldera, Antofagasta, Taltal, Tocopilla, Mejillones, and, farther north, Pisagua, and railroads penetrated the mountain barriers to the interior. Prior to World War I, Chile had a world monopoly on nitrate; in some years 3,000,000 tons were extracted, and the taxes on its export amounted to half the government's revenues. The development of synthetic methods of fixing nitrogen have since reduced the market to a regional one. Some sulfur is still mined in the high Cordillera. The region's chief source of revenue, however, is copper mining at Chuquicamata in the Calama basin.

Some farming is done in the desert's river oases, but this supports only a few thousand traditional cultivators. Lemons are grown at Pica, and a variety of products are cultivated on the shores of the salt marshes at San Pedro de Atacama. At Calama, near Chuquicamata, water from the Loa River irrigates potato and alfalfa fields.

Human habitation

Atacama road.

For humans to survive in and around the desert has been very challenging. It is not surprising then to discover in fact the Atacama is home to almost a million people. People are found mostly in coastal cities, fishing villages, oasis communities and scattered mining camps. In the altiplano, the descendants of the region's pre-Columbian natives (mostly Aymara and Atacama Indians) herd llamas and alpacas and grow crops with water from snowmelt streams.

Archaeological evidence indicates that the San Pedro area was the center of a Paleolithic civilization that built rock fortresses on the steep mountains encircling the valley.

The original inhabitants of the region were the Atacameños, an extinct Indian culture different from that of the Aymaras to the north and the Diaguitas to the south.

The Escondida Mine and Chuquicamata are also located within the Atacama.

The Pan-American Highway runs through the Atacama in a north-south trajectory.

The European Southern Observatory operates two major observatories in the Atacama Desert:

• The La Silla Observatory
• Located 130 km from Antofagasta at an altitude of 2635.43m and 12 km from the coast is the Paranal Observatory, which includes the Very Large Telescope.

A new radio astronomy observatory, called ALMA, is being built in the Atacama Desert by astronomers from Europe, Japan, and North America.

Another radio astronomy observatory, ACT, is being built on Cerro Toco in the Atacama Desert.

Great source of minerals

File:Chile-Tatio-Geyser.jpg

Geyser of Tatio in Atacama desert, Chile

The Atacama Desert holds major reserves of copper, gold, silver and industrial metals, it is the heart of Chile's mining industry. Chile's copper mines provide over 30% of the world's mine production of recoverable copper. It also contains the world's largest natural supply of sodium nitrate, which was mined on a large scale until the early 1940s. The Atacama border dispute between Chile and Bolivia began in the 1800s over these resources.

The Chuquicamata mine is the largest open-pit copper mine in the world, located 15 km north of the city of Calama in the region of Antofagasta. The mine is elliptical in form, with a surface of almost 8,000,000 m2, and it is 900 m deep. Copper from Chuquicamata is transported by rail southwest to Antofagasta. Approximately 30,000 people work in the remote region around the mine.

Chuquicamata is an opencast copper mine, where a relatively poor copper ore is mined in impressive huge amounts. Modern mining and smelting technology allows the usage of such depostits at unrivaled low costs. The ore contains only between 1.13% and 1.18% metals, most of it copper, but also molybdenum and selenium in a very low proportion.

Currently, the Atacama Desert is littered with approximately 170 abandoned nitrate (or "saltpeter") mining towns, almost all of which were shut down decades after the invention of synthetic nitrate in Germany at the turn of the 20th century. Some of these abandoned towns include Chacabuco, Humberstone, Santa Laura, Pedro de Valdivia, Puelma, Maria Elena and Oficina Anita. Chacabuco is a special case since it was later converted into a concentration camp during Pinochet's regime. To this day it is surrounded by 98 lost landmines and is guarded by one man who lives there alone.

The Atacama border dispute was a border dispute between Chile and Bolivia in the 1800s that ended in Chilean annexation of all of the Bolivian Coast and the southern tip of Bolivia's ally Peru, during the War of the Pacific (1879-1883). Later Peru and Argentina became involved in the dispute. Some still consider the dispute ongoing as Bolivia continues to claim a sovereign access to the Pacific Ocean.

Sources and Further Reading

• Braudel, Fernand, The perspective of the world, New York, Harper & Row, 1984, ISBN 0060153172
• Sagaris, Lake, Bone and dream : into the world's driest desert, Toronto, A.A. Knopf Canada, 2000, ISBN 0676972233
• Aarons, John and Claudio Vita-Finzi, , 1960. The useless land; a winter in the Atacama Desert, London, R. Hale, OCLC 2649656
• Roig, V. 1999. Atacama desert. Encyclopedia of deserts. University of Oklahoma Press, Norman (Oklahoma).
• Lustig, L. K. 1970. "Appraisal of research on geomorphology and surface hydrology of desert environments". Deserts of the world: An appraisal of research into their physical and biological environments. University of Arizona Press, Tucson.
• Dillon, M.O., and A.E. Hoffmann-J. 1997. "Lomas Formations of the Atacama Desert Northern Chile". Centres of Plant Diversity: A guide and Strategy for their Conservation. World Wildlife Fund. IUCN, Oxford, U.K.

External links

http://www.ls.eso.org/index.html http://www.eso.org/paranal/site/paranal.html

• Vesilind, Priit J., Parts of Chile's Atacama Desert haven't seen a drop of rain since recordkeeping began. Somehow, more than a million people squeeze life from this parched land, National Geographic, Accessed March 19, 2007
• Autonomous Robot Finds Life in Atacama Desert, Slash Dot, Accessed March 19, 2007
• Amos, Jonathan, December 8, 2005Chile desert's super-dry history, British Broadcasting Corporation, Accessed March 19, 2007
• Hudepohl, Gerhard, Atacama Desert Photographs, Atacama Photo, Accessed March 19, 2007

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