An oasis is a place in a desert, where water and vegetation can be found. They usually constitute more or less extensive portions of land fertilized by a water source in the middle of the sandy areas. Although they depend on a natural condition, such as the presence of water that can be dammed and used for irrigation, most oases, as we know them, are artificial.[1].
In these places there are usually small inhabited settlements, such as those in the Sahara region, the Arabian Peninsula or towns such as Pica "Pica (Chile)") in Chile, Ica in Peru or Parras de la Fuente in Mexico. In addition to growing crops for nearby residents and providing a water source, they also serve to supply travelers and caravans.
The illusion of perceiving them visually is called mirages.
The word 'oasis' comes from the Greek ὄασις [oasis], a term taken in turn from the ancient Egyptian uḥt, in demotic uḥỉ and in Coptic uaḥe, from which the Arabic wāḥa was also derived.[2].
Description
Oases develop in "hydrologically favored" locations that have attributes such as a high water table, seasonal lakes or blocked wadis.[3] Oases are formed when sources of fresh water, such as underground rivers or aquifers, irrigate the surface naturally or through artificial wells.[4] The presence of water on the surface or in the subsoil is necessary and local or regional management of this essential resource is strategic, but not sufficient to create these zones: Continuous human labor and know-how (a technical and social culture) are essential to maintaining these ecosystems.[5][6] Some of the possible human contributions to the maintenance of an oasis include the digging and maintenance of wells, the digging and maintenance of canals, and the continuous removal of opportunistic plants that threaten to gorge themselves on the water and fertility necessary to maintain human and animal food supplies.[7] Stereotypically, an oasis has a "central pond of open water surrounded by a ring of water-dependent shrubs and trees... which in turn are surrounded by a peripheral zone of transition to desert plants.
Rain showers provide groundwater to maintain natural oases, such as the Tuat. Impervious rock and stone substrates can trap water and hold it in pockets, or in long subsurface ridges with faults or volcanic dykes water can accumulate and seep to the surface. Any incidence of water is taken advantage of by migratory birds, which also pass seeds with their excrement that will grow at the edge of the water, forming an oasis. It can also be used to plant crops.
Climatic oases
Introduction
An oasis is a place in a desert, where water and vegetation can be found. They usually constitute more or less extensive portions of land fertilized by a water source in the middle of the sandy areas. Although they depend on a natural condition, such as the presence of water that can be dammed and used for irrigation, most oases, as we know them, are artificial.[1].
In these places there are usually small inhabited settlements, such as those in the Sahara region, the Arabian Peninsula or towns such as Pica "Pica (Chile)") in Chile, Ica in Peru or Parras de la Fuente in Mexico. In addition to growing crops for nearby residents and providing a water source, they also serve to supply travelers and caravans.
The illusion of perceiving them visually is called mirages.
The word 'oasis' comes from the Greek ὄασις [oasis], a term taken in turn from the ancient Egyptian uḥt, in demotic uḥỉ and in Coptic uaḥe, from which the Arabic wāḥa was also derived.[2].
Description
Oases develop in "hydrologically favored" locations that have attributes such as a high water table, seasonal lakes or blocked wadis.[3] Oases are formed when sources of fresh water, such as underground rivers or aquifers, irrigate the surface naturally or through artificial wells.[4] The presence of water on the surface or in the subsoil is necessary and local or regional management of this essential resource is strategic, but not sufficient to create these zones: Continuous human labor and know-how (a technical and social culture) are essential to maintaining these ecosystems.[5][6] Some of the possible human contributions to the maintenance of an oasis include the digging and maintenance of wells, the digging and maintenance of canals, and the continuous removal of opportunistic plants that threaten to gorge themselves on the water and fertility necessary to maintain human and animal food supplies.[7] Stereotypically, an oasis has a "central pond of open water surrounded by a ring of water-dependent shrubs and trees... which in turn are surrounded by a peripheral zone of transition to desert plants.
The oases of the Middle East and North Africa cover around 1,000,000 hectares. However, they support some 10 million people.[9] The marked proportion of oases and desert lands in the world means that the oasis ecosystem is "relatively tiny, rare and precious." [8].
There are 90 "great oases" in the Sahara Desert.[4] Part of their fertility may derive from irrigation systems called qanats', khettaras*,* lkhttarts*, or a variety of other regional names.*[10][11].
In some oasis systems, there is "a geometric system of raised channels that release controlled amounts of water into individual plots, soaking the soil."[11]
Oases often have human histories measured in millennia. In the archaeological excavations of Ein Gedi, in the Dead Sea Valley, evidence of settlements dating back to 6000 BC has been found. C.[12] Al-Ahsa") on the Arabian Peninsula shows evidence of human residence dating back to the Neolithic.[13].
Anthropologically, the oasis is "an area of sedentary life, which associates the city [medina] or village [ksar] with its surrounding food source, the palm grove, within a nomadic relational and circulatory system."[14].
The location of the oases has been of vital importance for trade and transportation routes in desert areas; caravans must travel through the oases so that food and water supplies can be replenished. Thus, political or military control of an oasis has in many cases meant control of trade on a specific route. For example, the oases of Awjila, Ghadames and Kufra, located in present-day Libya, have at various times been vital for north-south and east-west trade in the Sahara Desert. The location of the oases also influenced the Darb El Arba'īn trade route from Sudan to Egypt, as well as the Niger River caravan route to Tangier, Morocco.[8] The Silk Road "plotted its course from waterhole to waterhole, relying on oasis communities such as Turpan in China and Samarkand in Uzbekistan."[8].
According to the United Nations, "oases are at the very center of the general development of peri-Saharan countries due to their geographical location and the fact that they are the preferred migratory routes in times of famine or insecurity in the region."[10].
The oases of Oman, on the Arabian Peninsula near the Persian Gulf, differ somewhat from the Saharan form. Although they are still located in an arid or semi-arid area with a date palm forest, these oases are usually located under plateaus and "irrigated by springs or by aflaj"), systems of tunnels dug into the ground or carved into the rock to take advantage of underground aquifers." This rainwater harvesting system "never developed a serious salinity problem."[9].
In the arid areas of southwestern North America, there is a habitat form called Palm Oases (or Palm Series or Oasis Scrub Woodland) that has the Californian palm as its primary species.[15] These palm oases can be found in California, Arizona, Baja California, and Sonora.[15].
Systems in danger
Many historic oases have struggled with drought and inadequate maintenance.
According to a United Nations report on the future of oases in the Sahara and Sahel, “Increasingly... oases are under various pressures, greatly influenced by the effects of climate change, declining groundwater levels and the gradual loss of cultural heritage due to the fading of historical memory in relation to traditional water management techniques. These natural pressures are compounded by demographic pressures and the introduction of modern water pumping techniques that can disrupt traditional resource management systems, especially in the oases of the northern Sahara.
For example, five historic oases in the Western Desert of Egypt (Kharga, Dakhla, Farafra, Baharyia and Siwa) once had "flowing springs and wells", but due to the decline in groundwater heads due to overuse for land reclamation projects those water sources no longer exist and the oases suffer as a result.[16]
Morocco has lost two-thirds of its oasis habitat in the last 100 years due to heat, drought and water scarcity.
Egypt Oasis
Famous are the oases of Egypt, which were managed with the same attention as the other regions during the time of ancient Egypt. They served as a supply and resting place for the large caravans of Bedouin traders from the interior of Africa, mention being made of them in the Egyptian annals under the more general name of inhabitants of the Libyan territory.
Oasis in Peru
The Huacachina lagoon is an oasis located 5 km west of the city of Ica (in Peru) and 60 km east of the coast of the Pacific Ocean; It is presented as a true natural oasis in the middle of the white sands of the coastal desert of Peru. With emerald green waters, it arose due to the outcropping of underground currents and around it there is abundant vegetation composed of palm trees, eucalyptus (introduced species) and the species of mesquite known as huarango, which serve as a resting place for migratory birds that pass through this region. All this contributes to making Huacachina one of the most colorful and beautiful places on the Peruvian coast "Costa (Perú)").
Oasis in Chile
In the commune of Ovalle, Coquimbo Region, Chile, near the city of Ovalle, is the Fray Jorge Forest National Park, which is characterized by being a relict ecosystem with characteristics of a lush forest that is isolated and located next to the Atacama Desert, the driest on the planet.[17][18][19][20][21].
This remnant of temperate forest (the northernmost of the Valdivian humid rainforest), unlike the common oases that receive water from an aquifer source, its vegetation exists thanks to a particular climatic phenomenon, which is the condensation of the coastal fog (camanchaca), which is a product of the crossing of the Humboldt current with the winds coming from the sea; which creates a microclimate that allows this southernmost vegetation to exist.
Oasis in Morocco
In the High Atlas of Morocco, the Berber tribes that live in isolated and dry areas of the mountains have been self-sufficient for centuries thanks to a system that allows them to simultaneously integrate the production of vegetables, cereals and fruits with pasture for animals, through crop rotation and agroforestry techniques. This way of life maintained for generations in the oases has a strong cultural component. The water is extracted using a technique called khettara which consists of draining the aquifers through gravity tunnels. These cold oases in the eastern Atlas are part of the so-called World Important Agricultural Heritage Systems (GIAHS). The affected region covers just over 300,000 hectares and includes about 39,000 inhabitants.[22].
Oasis in Algeria
The ghout is a type of oasis in the northeast of the Algerian Sahara, in which groundwater is used to irrigate date palms in a desert terrain with shallow aquifers. The ghout cultivation system consists of excavating a cavity in the sand with a diameter of 80 to 200 m and one meter above the water table, so that the roots are in permanent contact with the water and irrigation is done naturally. For this reason, the United Nations considers it part of the World Important Agricultural Heritage Systems (GIAHS).[23].
• - Relict "Relict (biology)").
• - Herodotus: The island of the adventurous. In this story the word "oasis" appears for the first time.
• - Wikimedia Commons hosts a multimedia category on Oasis.
• - Wiktionary has definitions and other information about oasis.
References
[1] ↑ «G176: 5.5 De la adaptación a la creación de ambientes artificiales: los efectos de la presencia humana en las zonas áridas». ocw.unican.es. Consultado el 19 de julio de 2024.: https://ocw.unican.es/mod/page/view.php?id=660
[2] ↑ Corriente, Federico (1999). Diccionario de arabismos y voces afines en iberorromance. Madrid: Gredos, S. A. p. 408. ISBN 84-249-2243-3.
[3] ↑ Gebel, Hans Georg K. (2013). org/stable/43782872 «Culturas pastoriles de pozos del quinto milenio a.C. de Arabia: hipótesis sobre los orígenes de la vida en los oasis». Proceedings of the Seminar for Arabian Studies 43: 111-126. ISSN 0308-8421. JSTOR 43782872.: https://www.jstor.
[5] ↑ Vincent Battesti, El poder de una desaparición: El agua en la región de Jerid de Túnez in B. R. Johnston et al. (eds.), Water, Cultural Diversity & Global Environmental Change: Emerging Trends, Sustainable Futures?, 2012, UNESCO/Springer, p. 77-96. ISBN 978-9400717732.: http://hal.archives-ouvertes.fr/hal-00569337
[6] ↑ Battesti, Vincent (28 de mayo de 2015). «Recursos y apropiaciones: La vuelta a los oasis del Jerid (Túnez) tras la revolución». Études rurales 2 (192): 153-175. S2CID 126624438. doi:10.4000/etudesrurales.9954 – vía HAL Archives Ouvertes.: https://hal.archives-ouvertes.fr/hal-01154717
[7] ↑ Cutler, B. Environmental History of the Maghreb, 1800-Present. Oxford Research Encyclopedia of African History. Recuperado el 25 Ene. 2023, de https://oxfordre-com.wikipedialibrary.idm.oclc.org/africanhistory/view/10.1093/acrefore/9780190277734.001.0001/acrefore-9780190277734-e-983.
[12] ↑ org/issues/340-1905/letter-from/7568-life-in-a-busy-oasis «Vida en un oasis bullicioso - Archaeology Magazine». www.archaeology.org. Consultado el 23 de septiembre de 2022.: https://www.archaeology.
[14] ↑ Hadagha, Fatma Zohra; Farhi, Bourhane Eddine; Farhi, Abdallah; Petrisor, Alexandru Ionut (29 de diciembre de 2018). «Multifuncionalidad del ecosistema del oasis. Estudio de caso: Oasis de Biskra, Argelia». Journal of Contemporary Urban Affairs 2 (3): 31-39. ISSN 2475-6156. S2CID 165113883. doi:10.25034/ijcua.2018.4716.: https://ijcua.com/index.php/ijcua/article/view/111
[16] ↑ Aziz, Ameer; Sabet, Hassan S.; Ghoubachi, Saad Y.; Abu Risha, Usama A. (1 de julio de 2022). «El origen y las condiciones de recarga de las aguas subterráneas en el oasis de Farafra, desierto occidental, Egipto». Scientific African 16: e01179. S2CID 248041232. doi:10.1016/j.sciaf.2022.e01179.: https://api.semanticscholar.org/CorpusID:248041232
[19] ↑ «Driest Place: Atacama Desert, Chile - Even the Driest Place on Earth Has Water» (HTM) (en inglés). www.extremescience.com. 2013. Consultado el 2 de enero de 2014.: http://www.extremescience.com/driest.htm
[21] ↑ Amos, Jonathan (8 de diciembre de 2005). «Chile desert's super-dry history» (STM) (en inglés). news.bbc.co.uk. Consultado el 2 de enero de 2014.: http://news.bbc.co.uk/1/hi/sci/tech/4437153.stm
Rain showers provide groundwater to maintain natural oases, such as the Tuat. Impervious rock and stone substrates can trap water and hold it in pockets, or in long subsurface ridges with faults or volcanic dykes water can accumulate and seep to the surface. Any incidence of water is taken advantage of by migratory birds, which also pass seeds with their excrement that will grow at the edge of the water, forming an oasis. It can also be used to plant crops.
The oases of the Middle East and North Africa cover around 1,000,000 hectares. However, they support some 10 million people.[9] The marked proportion of oases and desert lands in the world means that the oasis ecosystem is "relatively tiny, rare and precious." [8].
There are 90 "great oases" in the Sahara Desert.[4] Part of their fertility may derive from irrigation systems called qanats', khettaras*,* lkhttarts*, or a variety of other regional names.*[10][11].
In some oasis systems, there is "a geometric system of raised channels that release controlled amounts of water into individual plots, soaking the soil."[11]
Oases often have human histories measured in millennia. In the archaeological excavations of Ein Gedi, in the Dead Sea Valley, evidence of settlements dating back to 6000 BC has been found. C.[12] Al-Ahsa") on the Arabian Peninsula shows evidence of human residence dating back to the Neolithic.[13].
Anthropologically, the oasis is "an area of sedentary life, which associates the city [medina] or village [ksar] with its surrounding food source, the palm grove, within a nomadic relational and circulatory system."[14].
The location of the oases has been of vital importance for trade and transportation routes in desert areas; caravans must travel through the oases so that food and water supplies can be replenished. Thus, political or military control of an oasis has in many cases meant control of trade on a specific route. For example, the oases of Awjila, Ghadames and Kufra, located in present-day Libya, have at various times been vital for north-south and east-west trade in the Sahara Desert. The location of the oases also influenced the Darb El Arba'īn trade route from Sudan to Egypt, as well as the Niger River caravan route to Tangier, Morocco.[8] The Silk Road "plotted its course from waterhole to waterhole, relying on oasis communities such as Turpan in China and Samarkand in Uzbekistan."[8].
According to the United Nations, "oases are at the very center of the general development of peri-Saharan countries due to their geographical location and the fact that they are the preferred migratory routes in times of famine or insecurity in the region."[10].
The oases of Oman, on the Arabian Peninsula near the Persian Gulf, differ somewhat from the Saharan form. Although they are still located in an arid or semi-arid area with a date palm forest, these oases are usually located under plateaus and "irrigated by springs or by aflaj"), systems of tunnels dug into the ground or carved into the rock to take advantage of underground aquifers." This rainwater harvesting system "never developed a serious salinity problem."[9].
In the arid areas of southwestern North America, there is a habitat form called Palm Oases (or Palm Series or Oasis Scrub Woodland) that has the Californian palm as its primary species.[15] These palm oases can be found in California, Arizona, Baja California, and Sonora.[15].
Systems in danger
Many historic oases have struggled with drought and inadequate maintenance.
According to a United Nations report on the future of oases in the Sahara and Sahel, “Increasingly... oases are under various pressures, greatly influenced by the effects of climate change, declining groundwater levels and the gradual loss of cultural heritage due to the fading of historical memory in relation to traditional water management techniques. These natural pressures are compounded by demographic pressures and the introduction of modern water pumping techniques that can disrupt traditional resource management systems, especially in the oases of the northern Sahara.
For example, five historic oases in the Western Desert of Egypt (Kharga, Dakhla, Farafra, Baharyia and Siwa) once had "flowing springs and wells", but due to the decline in groundwater heads due to overuse for land reclamation projects those water sources no longer exist and the oases suffer as a result.[16]
Morocco has lost two-thirds of its oasis habitat in the last 100 years due to heat, drought and water scarcity.
Egypt Oasis
Famous are the oases of Egypt, which were managed with the same attention as the other regions during the time of ancient Egypt. They served as a supply and resting place for the large caravans of Bedouin traders from the interior of Africa, mention being made of them in the Egyptian annals under the more general name of inhabitants of the Libyan territory.
Oasis in Peru
The Huacachina lagoon is an oasis located 5 km west of the city of Ica (in Peru) and 60 km east of the coast of the Pacific Ocean; It is presented as a true natural oasis in the middle of the white sands of the coastal desert of Peru. With emerald green waters, it arose due to the outcropping of underground currents and around it there is abundant vegetation composed of palm trees, eucalyptus (introduced species) and the species of mesquite known as huarango, which serve as a resting place for migratory birds that pass through this region. All this contributes to making Huacachina one of the most colorful and beautiful places on the Peruvian coast "Costa (Perú)").
Oasis in Chile
In the commune of Ovalle, Coquimbo Region, Chile, near the city of Ovalle, is the Fray Jorge Forest National Park, which is characterized by being a relict ecosystem with characteristics of a lush forest that is isolated and located next to the Atacama Desert, the driest on the planet.[17][18][19][20][21].
This remnant of temperate forest (the northernmost of the Valdivian humid rainforest), unlike the common oases that receive water from an aquifer source, its vegetation exists thanks to a particular climatic phenomenon, which is the condensation of the coastal fog (camanchaca), which is a product of the crossing of the Humboldt current with the winds coming from the sea; which creates a microclimate that allows this southernmost vegetation to exist.
Oasis in Morocco
In the High Atlas of Morocco, the Berber tribes that live in isolated and dry areas of the mountains have been self-sufficient for centuries thanks to a system that allows them to simultaneously integrate the production of vegetables, cereals and fruits with pasture for animals, through crop rotation and agroforestry techniques. This way of life maintained for generations in the oases has a strong cultural component. The water is extracted using a technique called khettara which consists of draining the aquifers through gravity tunnels. These cold oases in the eastern Atlas are part of the so-called World Important Agricultural Heritage Systems (GIAHS). The affected region covers just over 300,000 hectares and includes about 39,000 inhabitants.[22].
Oasis in Algeria
The ghout is a type of oasis in the northeast of the Algerian Sahara, in which groundwater is used to irrigate date palms in a desert terrain with shallow aquifers. The ghout cultivation system consists of excavating a cavity in the sand with a diameter of 80 to 200 m and one meter above the water table, so that the roots are in permanent contact with the water and irrigation is done naturally. For this reason, the United Nations considers it part of the World Important Agricultural Heritage Systems (GIAHS).[23].
• - Relict "Relict (biology)").
• - Herodotus: The island of the adventurous. In this story the word "oasis" appears for the first time.
• - Wikimedia Commons hosts a multimedia category on Oasis.
• - Wiktionary has definitions and other information about oasis.
References
[1] ↑ «G176: 5.5 De la adaptación a la creación de ambientes artificiales: los efectos de la presencia humana en las zonas áridas». ocw.unican.es. Consultado el 19 de julio de 2024.: https://ocw.unican.es/mod/page/view.php?id=660
[2] ↑ Corriente, Federico (1999). Diccionario de arabismos y voces afines en iberorromance. Madrid: Gredos, S. A. p. 408. ISBN 84-249-2243-3.
[3] ↑ Gebel, Hans Georg K. (2013). org/stable/43782872 «Culturas pastoriles de pozos del quinto milenio a.C. de Arabia: hipótesis sobre los orígenes de la vida en los oasis». Proceedings of the Seminar for Arabian Studies 43: 111-126. ISSN 0308-8421. JSTOR 43782872.: https://www.jstor.
[5] ↑ Vincent Battesti, El poder de una desaparición: El agua en la región de Jerid de Túnez in B. R. Johnston et al. (eds.), Water, Cultural Diversity & Global Environmental Change: Emerging Trends, Sustainable Futures?, 2012, UNESCO/Springer, p. 77-96. ISBN 978-9400717732.: http://hal.archives-ouvertes.fr/hal-00569337
[6] ↑ Battesti, Vincent (28 de mayo de 2015). «Recursos y apropiaciones: La vuelta a los oasis del Jerid (Túnez) tras la revolución». Études rurales 2 (192): 153-175. S2CID 126624438. doi:10.4000/etudesrurales.9954 – vía HAL Archives Ouvertes.: https://hal.archives-ouvertes.fr/hal-01154717
[7] ↑ Cutler, B. Environmental History of the Maghreb, 1800-Present. Oxford Research Encyclopedia of African History. Recuperado el 25 Ene. 2023, de https://oxfordre-com.wikipedialibrary.idm.oclc.org/africanhistory/view/10.1093/acrefore/9780190277734.001.0001/acrefore-9780190277734-e-983.
[12] ↑ org/issues/340-1905/letter-from/7568-life-in-a-busy-oasis «Vida en un oasis bullicioso - Archaeology Magazine». www.archaeology.org. Consultado el 23 de septiembre de 2022.: https://www.archaeology.
[14] ↑ Hadagha, Fatma Zohra; Farhi, Bourhane Eddine; Farhi, Abdallah; Petrisor, Alexandru Ionut (29 de diciembre de 2018). «Multifuncionalidad del ecosistema del oasis. Estudio de caso: Oasis de Biskra, Argelia». Journal of Contemporary Urban Affairs 2 (3): 31-39. ISSN 2475-6156. S2CID 165113883. doi:10.25034/ijcua.2018.4716.: https://ijcua.com/index.php/ijcua/article/view/111
[16] ↑ Aziz, Ameer; Sabet, Hassan S.; Ghoubachi, Saad Y.; Abu Risha, Usama A. (1 de julio de 2022). «El origen y las condiciones de recarga de las aguas subterráneas en el oasis de Farafra, desierto occidental, Egipto». Scientific African 16: e01179. S2CID 248041232. doi:10.1016/j.sciaf.2022.e01179.: https://api.semanticscholar.org/CorpusID:248041232
[19] ↑ «Driest Place: Atacama Desert, Chile - Even the Driest Place on Earth Has Water» (HTM) (en inglés). www.extremescience.com. 2013. Consultado el 2 de enero de 2014.: http://www.extremescience.com/driest.htm
[21] ↑ Amos, Jonathan (8 de diciembre de 2005). «Chile desert's super-dry history» (STM) (en inglés). news.bbc.co.uk. Consultado el 2 de enero de 2014.: http://news.bbc.co.uk/1/hi/sci/tech/4437153.stm