Recuperamos este video que se hizo para la Semana de la Ciencia de 2022, en la que participamos con una exposición sobre la desertificación.
Mostrando entradas con la etiqueta Desiertos. Mostrar todas las entradas
Mostrando entradas con la etiqueta Desiertos. Mostrar todas las entradas
viernes, 22 de noviembre de 2024
lunes, 2 de diciembre de 2019
jueves, 21 de noviembre de 2019
Videos: Planeta arena
Os dejamos unos vídeos de la serie documental "Planeta Arena", sobre los principales desiertos del mundo. Si tenéis tiempo para verlos, merece la pena. Son 5 capítulos de unos 42 minutos cada uno.
1. Sahara, reconquistando tierras perdidas.
2. Aralkun, el desierto más joven del mundo.
3. China contra el dragón amarillo.
4. Atacama, las búsqueda del agua.
5. Australia, el continente desértico.
1. Sahara, reconquistando tierras perdidas.
2. Aralkun, el desierto más joven del mundo.
3. China contra el dragón amarillo.
4. Atacama, las búsqueda del agua.
5. Australia, el continente desértico.
lunes, 2 de julio de 2018
World Atlas of Desertificacion
Se acaba de publicar la tercera edición del World Atlas of Desertification.
Puede descargarse del siguiente enlace:
https://wad.jrc.ec.europa.eu/
Cherlet, M., Hutchinson, C., Reynolds, J., Hill, J., Sommer, S., von Maltitz, G. (Eds.), World Atlas of Desertification, Publication Office of the European Union, Luxembourg, 2018.
Puede descargarse del siguiente enlace:
https://wad.jrc.ec.europa.eu/
Cherlet, M., Hutchinson, C., Reynolds, J., Hill, J., Sommer, S., von Maltitz, G. (Eds.), World Atlas of Desertification, Publication Office of the European Union, Luxembourg, 2018.
jueves, 8 de marzo de 2018
Las Bardenas después de la lluvia
Algunos se sorprenden porque nos gustan las zonas áridas, los desiertos y la erosión. Quizás después de ver estas imágenes empiecen a entendernos.
El viernes 2 de marzo, las Bardenas Reales de Navarra lucían con una gran belleza, después de varios días previos de nieve y lluvia.
El viernes 2 de marzo, las Bardenas Reales de Navarra lucían con una gran belleza, después de varios días previos de nieve y lluvia.
viernes, 10 de marzo de 2017
jueves, 19 de enero de 2017
Los círculos de Namibia
¿Por qué en algunos lugares del mundo surgen unos círculos perfectos donde la vegetación no crece? ¿Es obra de extraterrestres, son señales destinadas a los dioses realizadas por moradores milenarios de esas tierras? A decir verdad, los científicos barajaban opciones menos atractivas que éstas, pero el misterio merecía algo de dedicación y a ello se puso un grupo de investigadores que ahora publica en Nature-que le dedica su portada- la solución más factible a este prolongado enigma.
Portada de Nature
Este estudio analizó una serie de calvas que pueden encontrarse sobre el terreno en el desierto de Namibia, llamadas popularmente círculos mágicos. El fenómeno, sin embargo, se repite en otros lugares del planeta: en Brasil los llaman murundus y en Sudáfrica heuweltjies, pero son esencialmente el mismo fenómeno misterioso.
En febrero del año pasado, se localizaron nuevos círculos en un remoto desierto australiano y un equipo de científicos dirigidos por Ehud Meron, investigador de la Ben-Gurion University, se animó a publicar en la revista PNAS una nueva hipótesis sobre su origen, que afirmaba que estos -como los de Namibia- se debía a una especie de retroalimentación de la vegetación y el agua presentes en la zona, que generaría unos patrones geométricos determinados.
La tesis contradecía la otra gran hipótesis racional imperante: la demostrada tres años antes por un investigador de la Universidad de Hamburgo que publicó sus conclusiones en Science y que sostenía que era la oculta labor de las termitas Psammotermes allocerus, que retiraban la vegetación de vida corta que aparecía tras la lluvia y formaban así las características calvas de los círculos mágicos namibios.
La nueva hipótesis, formulada por la investigadora de la Universidad de Princeton Corina Tarnita es un ni para ti ni para mí y reconcilia ambas perspectivas competitivas integrándolas en simulaciones de modelos, que luego validan con datos de campo de cuatro continentes.
Demuestran que, en lugar de una u otra, una combinación de las colonias subterráneas de insectos sociales de la misma especie y la retroalimentación entre las plantas y el agua puede explicar los patrones de vegetación regulares auto-organizados.
Los autores concluyen que se deben considerar múltiples mecanismos de autoorganización ecológica cuando se trata de explicar estas características del paisaje y descartan así optar por una u otra hipótesis. ¿Sera ésta la última vez que se expliquen los círculos mágicos de Namibia?
Fuente: Elespañol.com
jueves, 29 de septiembre de 2016
El desierto y el fuego
En este artículo de la NASA se muestra el papel del fuego en la configuración de un paisaje desértico de Australia. El artículo original se titula "A desert landcape scarred by fire".
The Gibson Desert in Western Australia is a vast, desolate, and beautiful place. Aside from patchy tufts of desert grass and the occasional shrub or tree, the fire-prone landscape is mainly one of undulating red dunes, desert pavement, and sandy plains.
For tens of thousands of years, nomadic Aboriginal people traveled the harsh landscape around Lake MacKay looking for food and water. That nomadic lifestyle was transformed when the British military began missile tests in the region in 1950s; most of the Pintupi people living in the area ended up in small settlements such as Kiwirrkurra.
A change in the lifestyle of the Pintupi resulted in some fairly dramatic changes to the landscape as well. By comparing aerial imagery from the 1950s with a series of more recent images collected by Landsat satellites, an ecologist with Western Australia’s forest department Neil Burrows found that fire scars around Lake Mackay grew much larger after the Pintupi were resettled.
The Pintupi used to light fires to encourage the growth of certain edible plants that were only abundant in years after a fire. Pintupi hunters also used fires to drive game animals from their burrows, and hunting in a recently burned area made game easier to track.
On November 19, 2015, the Operational Land Imager (OLI) on Landsat 8 satellite acquired the image at the top of the page—a burn scar in the Gibson Desert. The burn scar is light orange compared to the darker orange areas that have not burned recently. The vegetation on the unburned parts of the landscape is primarily the desert grass Triodia (see photo below). The gray area south of Kiwirrkurra is a range of stony hills. Imagery collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on NASA’s Aqua and Terra satellites indicate that a thunderstorm on November 7 triggered the fire.
The burn scar is located about 80 kilometers (50 miles) southwest of Lake Mackay (-23.284888 South, 127.859769 East.) The lower image shows a broader view. Note the size of many of the burn scars in this area. Without regular burning, flammable vegetation builds up and fires tend to be large and intense.
“At about 2,500 hectares (6,100 acres), this is a very small fire these days,” said Burrows. “Since the cessation of traditional aboriginal burning, it is not uncommon for a single fire to be several hundred thousand hectares. In 2012, to the south of this fire, a fire burnt 3.2 million hectares (7.9 million acres) over two weeks.”
All of these big fires may be doing more than changing the appearance of the landscape. Ecologists report sharp declines in the population of some native mammals in the area. Burrows and some other ecologists argue that the changing fire regime is likely one of the causes of the decline.
Link NASA
References
BBC (2014, December 23) The day the Pintupi Nine entered the modern world. Accessed September 23, 2016.
Burrows, N.D. et al. (2006) Evidence of altered fire regimes in the Western Desert region of Australia.Conservation Science, 5 (3), 272-284.
Burbridge & Jenkins (1984) Endangered vertebrates of Australia and its island territories. Report of the Working Group on Endangered Fauna of the Standing Committee of the Council of Nature Conservation Ministers.
National Museum of Australia (2011) Pintupi’s 30th anniversary Accessed September 23, 2016.
NASA Earth Observatory images by Joshua Stevens, using Landsat data from the U.S. Geological Survey. Photo courtesy of Neil Burrows. Note: Though taken in the Gibson Desert, the photo does not show the fire that caused the burn scar highlighted in the Landsat image. Caption by Adam Voiland. Congratulations to Adam Liefloff for being the first to weigh in with an answer for the September Puzzler on Earth Matters. Congratulations also to Cait Stuart, Tyler Keaton, and Rosemary Butt for being some of the first readers to solve the puzzler on Facebook.
The Gibson Desert in Western Australia is a vast, desolate, and beautiful place. Aside from patchy tufts of desert grass and the occasional shrub or tree, the fire-prone landscape is mainly one of undulating red dunes, desert pavement, and sandy plains.
For tens of thousands of years, nomadic Aboriginal people traveled the harsh landscape around Lake MacKay looking for food and water. That nomadic lifestyle was transformed when the British military began missile tests in the region in 1950s; most of the Pintupi people living in the area ended up in small settlements such as Kiwirrkurra.
A change in the lifestyle of the Pintupi resulted in some fairly dramatic changes to the landscape as well. By comparing aerial imagery from the 1950s with a series of more recent images collected by Landsat satellites, an ecologist with Western Australia’s forest department Neil Burrows found that fire scars around Lake Mackay grew much larger after the Pintupi were resettled.
The Pintupi used to light fires to encourage the growth of certain edible plants that were only abundant in years after a fire. Pintupi hunters also used fires to drive game animals from their burrows, and hunting in a recently burned area made game easier to track.
On November 19, 2015, the Operational Land Imager (OLI) on Landsat 8 satellite acquired the image at the top of the page—a burn scar in the Gibson Desert. The burn scar is light orange compared to the darker orange areas that have not burned recently. The vegetation on the unburned parts of the landscape is primarily the desert grass Triodia (see photo below). The gray area south of Kiwirrkurra is a range of stony hills. Imagery collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on NASA’s Aqua and Terra satellites indicate that a thunderstorm on November 7 triggered the fire.
The burn scar is located about 80 kilometers (50 miles) southwest of Lake Mackay (-23.284888 South, 127.859769 East.) The lower image shows a broader view. Note the size of many of the burn scars in this area. Without regular burning, flammable vegetation builds up and fires tend to be large and intense.
October 18, 2015
November 19, 2015
November 19, 2015
2015
“At about 2,500 hectares (6,100 acres), this is a very small fire these days,” said Burrows. “Since the cessation of traditional aboriginal burning, it is not uncommon for a single fire to be several hundred thousand hectares. In 2012, to the south of this fire, a fire burnt 3.2 million hectares (7.9 million acres) over two weeks.”
All of these big fires may be doing more than changing the appearance of the landscape. Ecologists report sharp declines in the population of some native mammals in the area. Burrows and some other ecologists argue that the changing fire regime is likely one of the causes of the decline.
Link NASA
References
BBC (2014, December 23) The day the Pintupi Nine entered the modern world. Accessed September 23, 2016.
Burrows, N.D. et al. (2006) Evidence of altered fire regimes in the Western Desert region of Australia.Conservation Science, 5 (3), 272-284.
Burbridge & Jenkins (1984) Endangered vertebrates of Australia and its island territories. Report of the Working Group on Endangered Fauna of the Standing Committee of the Council of Nature Conservation Ministers.
National Museum of Australia (2011) Pintupi’s 30th anniversary Accessed September 23, 2016.
NASA Earth Observatory images by Joshua Stevens, using Landsat data from the U.S. Geological Survey. Photo courtesy of Neil Burrows. Note: Though taken in the Gibson Desert, the photo does not show the fire that caused the burn scar highlighted in the Landsat image. Caption by Adam Voiland. Congratulations to Adam Liefloff for being the first to weigh in with an answer for the September Puzzler on Earth Matters. Congratulations also to Cait Stuart, Tyler Keaton, and Rosemary Butt for being some of the first readers to solve the puzzler on Facebook.
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