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Imaggeo

Imaggeo on Mondays: A painted forest fire

Imaggeo on Mondays: A painted forest fire

This week’s featured image may appear to be a painted landscape, but the picture is in fact a photo, taken ten years ago by Victoria Arcenegui, an associate professor at Miguel Hernández University in Spain, during a controlled forest fire in northern Portugal.

The blaze is actually hot enough to distort the image, making some of the flames appear as brush strokes, beautifully blurring together the colours of the fire, trees and smoke.

Intense heat such as this influences how light travels to both the human eye and a camera lens. As air warms it expands, while colder air becomes denser. As a result, light travels quicker through thinner warm air but is refracted more in denser cool air. So when there are shifting pockets of cold and hot air, the speed of light through air is constantly changing, creating a shimmering effect.

The prescribed fire in this photo is not only showcasing an interesting phenomenon, but is also providing an important service to the region’s ecosystem. For decades, forest fires were often considered detrimental to the environment, however, researchers say that small natural fires help strengthen ecosystems. For example, by burning old dead vegetation, these fires cycle nutrients back to the soil and clear space for new plants to grow. In addition, some plant rely on fires to spread or activate seeds. Historically, many wildlife management programmes prevented smaller fires from removing vegetation, subsequently creating overgrown forests, which are more susceptible to larger, more destructive fires.

Now, many researchers are studying the effectiveness of prescribed burning, where forests are periodically set on fire in a controlled setting to replicate the ecological impact of natural fires and reduce wildfire risk.

By Olivia Trani, EGU Communications Officer

References

Santín, C. and Doerr, S. H.: Fire effects on soils: the human dimension, Philosophical Transactions of the Royal Society B: Biological Sciences, 371(1696), 20150171, doi:10.1098/rstb.2015.0171, 2016.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Imaggeo on Mondays: Dust devil sighting in the Atacama Desert

Imaggeo on Mondays: Dust devil sighting in the Atacama Desert

Dust devils are like miniature tornadoes, they form when a pocket of hot air near the surface moves fast upward and meets cooler air above it. As the air rapidly rises, the column of hot air is stretched vertically, thereby moving mass closer to the axis of rotation, which causes intensification of the spinning effect by conservation of angular momentum. In the Atacama Desert [in Chile] they are really common, and the desert is a perfect “lab” to observe and study their formation!

Description by Rita Nogherotto, as it first appeared on imaggeo.egu.eu.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Imaggeo on Mondays: Indonesian mangroves and tsunamis

Imaggeo on Mondays: Indonesian mangroves and tsunamis

Pictured here is a solitary mangrove tree, rooted off the northern coast of the Indonesian island Flores. While this tree has the shallow sandy reef to itself, mangroves are often found clumped together in large forests covering tropical and subtropical coastlines. The propped-up roots of mangrove trees often tangle together, creating a dense natural barrier that can weaken the coastal impact of ocean tides, currents and storms. As a consequence, islands with mangrove forests on their coastlines experience less erosion and less damage from storm surges compared to barer shorelines.

Mangroves are also often said to provide protection against tsunami destruction. Indeed, there have been several cases in which mangroves trees were believed to have curtailed the devastating effect of tsunami waves. Recent research suggests that extensive mangrove forests hundreds of metres wide have been able to reduce tsunami wave heights by 5-30 percent.

Unfortunately, over the past decades, these environmental benefits are now under threat due to deforestation. About half of the global mangrove population (32 million hectares) has been wiped out, often to make way for fish farming operations. In Indonesia, mangrove ecosystem decline has been largely attributed to developing shrimp ponds and logging activities. There are now a number of places where mangrove plantations are supported by local individuals and governments.

Jörn Behrens, a professor of numerical methods in Earth sciences at the University of Hamburg in Germany, captured this shot while on a field trip in Indonesia. He and his colleagues were looking for traces of the powerful 1992 tsunami that struck the coast of the Indonesia island of Flores and other nearby smaller islands.

The tsunami, triggered by a magnitude 7.9 earthquake, sent waves reaching 4 to 27-metres high on the island’s northeastern coast, even destroying a whole village situated on the nearby island Babi. About 2,500 residents and tourists died from the event, with hundreds more injured, and thousands more homeless.

The 1992 Flores tsunami was also one of the first such events documented by an international survey that adhered to internationally accepted post-tsunami assessment standards.  On their field trip Behrens and his colleagues revisited some of sites assessed by the 1992 post-tsunami survey, spoke to eye witnesses, learned about the region’s current mitigation measures, and exchanged latest results from modeling and experimental tsunami research.

While on this field trip, Behrens came across this solitary mangrove, surrounded by what appears to be young mangrove propagules growing out from the water.

By Olivia Trani, EGU Communications Officer

References

Spalding M, McIvor A, Tonneijck FH, Tol S and van Eijk P (2014) Mangroves for coastal defence. Guidelines for coastal managers & policy makers. Wetlands International and The Nature Conservancy.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Imaggeo on Mondays: Penguins – a biogeochemical link between sea and land

Imaggeo on Mondays: Penguins – a biogeochemical link between sea and land

A couple of Chinstrap penguins (Pygoscelis antarctica) at their nesting site on Deception Island, maritime Antarctica. Sea birds contribute importantly to biogeochemical cycles in coastal ecosystems and on islands. Feeding on the marine food chain and nesting on land, they carry large amounts of marine nutrients into terrestrial ecosystems. This might be of particular importance for the nitrogen (N) cycle of terrestrial ecosystems in the antarctic. In the form of ammonia, marine derived N can travel far inland with the wind, and perhaps represent an important nutrient source for the growth of mosses.

Description by Daniel Wasner, as it first appeared on imaggeo.egu.eu.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.