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Imaggeo

Imaggeo on Mondays: A walk at the glacier

Imaggeo on Mondays: A walk at the glacier

In 2012 I had the opportunity to help lead a teaching excursion to the Norwegian archipelago Svalbard. On this trip, geography students from the Ruhr-University of Bochum in Germany had the chance to learn more about the nature of this fascinating island.

In addition to Svalbard’s climatology and the wildlife, the region’s glaciology and geomorphology were the main topics we focused on. For example, we walked to the glacier ice, measured the glacier drainage flow and assigned various glacial debris accumulations (also known as moraines) to their genesis. Furthermore, PhD students from the local university showed us field experiments on how the region’s permafrost melts and wet soils slide downhill (also known as solifluction). We could see the giant glacier tongues with ice fronts at the sea level on a boat trip to the old coal mining town of Longyearbyen. The debris cover and the incredibly large medial moraine (debris that collects when two glaciers merge together) of the pictured glacier particularly impressed us.

We were astonished when the two polar bears came into sight after a short moment. Of course, we had secretly hoped to see polar bears on this excursion, but when it actually happened, not only the glaciers and the whole landscape seemed bigger, but also the wild nature of Svalbard got much more impressive. For me, my colleague André and my students this experience will be unforgettable.

By A. Martina Grudzielanek, Ruhr-University of Bochum, Germany

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: An expedition to better understand Antarctic soils

Imaggeo on Mondays: An expedition to better understand Antarctic soils

A dramatic evening sky puts the frame to a photo taken during the Brazilian Antarctic expedition to James Ross Island in 2016. Brazilian palaeontologists and soil scientists together with German soil scientists spent over 40 days on the island to search for fossils and sample soils at various locations of the northern part of the island.

The island was named after Sir James Clark Ross who led the British expedition in 1842, which first charted locations at the eastern part of the island. James Ross Island is part of Graham Land, the northern portion of the Antarctic Peninsula, separated from South America by the stormy Drake sea passage.

Map of the Antarctic Peninsula featuring the James Ross Archipelago (Credit: The Scientific Committee on Antarctic Research, Antarctic Digital Database Map Viewer)

This photo was taken in the northern Ulu Peninsula, which is the northernmost part of the relatively large James Ross Island and the largest ice-free area in the Antarctic Peninsula region. The island’s characteristic appearance is formed by Late Neogene volcanic rocks (3-7 million years old) over fossil rich Late Cretaceous sandstones (66-120 million years old).

In the photo we are looking from a higher marine terrace at the Santa Martha Cove, the ‘home’ to the 2016 Brazilian Antarctic expedition, towards the steep cliffs of Lachman Crags, a characteristic mesa formed by Late Neogene lava flows. The Lachman Crags mesa, the Spanish word for tablelands, dominates the landscape of the northern part of the Ulu Peninsula. Above the cliffs visible in the photo, a glacier covered plateau stretches to the Northwest.

The marine terrace on which the tent is standing is comprised of a flat area that has been ice-free for approximately 6000 years and thus makes for a great model system to study soil development after glacial retreat. The ground is composed of a mixture of volcanic rocks and Cretaceous sandstones rich in all sorts of fossils, from fossilised wood to shark teeth, ammonites and reptile bones.

The strong winds that can start in Antarctica from one moment to the other and the very low precipitation led to the characteristic desert pavement, with stones sorted in a flat arrangement on top of the fine textured, deeply weathered permafrost soils. Although these soils host a surprisingly high number of microorganisms, most terrestrial life is restricted to wetter areas surrounding fresh water lakes and melt water streams. Thus lakes and snow meltwater-fed areas make for higher primary production of algae and mosses, fostering biodiversity and soil development by organic matter input.

As there are no larger bird rookeries on James Ross Island the only way sea-derived nutrients reach the Ulu Peninsula is by a rather grim feature:  dead seal carcasses that lie distributed across the lowlands (< 150 m asl) of the Ulu Peninsula. Carcasses fertilise the soils in their direct vicinity while slowly decomposing over decades, thus feeding small patches of lichens and mosses within the barren cold arid desert. The region is thus an illustration of the harsh Antarctic environment where even Weddell seals, animals that are well adapted for the living in dense pack ice during the polar night, die when losing track on land on the way to the water.

By Carsten Müller, Technical University of Munich Chair of Soil Science, Germany

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: A lifeline between light and shadow

Imaggeo on Mondays: A lifeline between light and shadow

The Rapaälven making its way through the Rapadalen valley in Northern Sweden. After over a week of hiking through pure wilderness I reached the summit of Skierffe together with three friends. We were just blown away by the view and completely in awe for the beautiful shape of the rivers course… little lakes in between river channels of different sizes as well as dense vegetation forming a habitat for so many animals.. all controlled by erosion and the force of the water cycle…

A few days later we learned how difficult it is to hike through terrain like this for humans but how fast and quiet a moose can move right across the valley.

The Rapaälven is the biggest river in the Sarek National Park, the Swedish part of Lapland. Four smaller rivers (Smájllajåkkå, Mikkájåkkå, Guohperjåkkå, Áhkáåkkå) form this 75km long stream that drains around 30 different glaciers and the surrounding national park.

Description by Florian Konrad, 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: how short-term storms can impact our landscapes

Imaggeo on Mondays: how short-term storms can impact our landscapes

In the Sierra de Aconquija, a mountain range in the southern Central Andes of Argentina, strong storms often come and go at a moment’s notice, but they can have a long-lasting impact on the Earth’s surface.

The thunderstorm cell featured in this photo formed in less than half an hour, giving all those nearby only a few minutes to take cover. Mitch D’Arcy, a geomorphologist and postdoctoral researcher at the University of Potsdam and the GFZ German Research Centre for Geosciences, had the opportunity to witness this storm (and snap this picture!) while carrying out field work in the area.

“It was a spectacular experience, pouring heavy rain onto a very localised part of the mountain range, but it was also a hazard because the storm was quickly moving towards us with a lot of lightning. Without any trees around, we were likely targets for lightning strikes!” said D’Arcy. Luckily, he and his colleagues were able to find shelter in their truck while the huge downpour passed over them.

These kinds of thunderstorms are short-lived, but have intense precipitation rates. In this case, the temperature dropped by 14 degrees Celsius, and the storm was accompanied by heavy hail and lightning. And while these natural hazards are transient, they can have a long-term impact on the region’s landscape. Severe storms are capable of triggering landslides and floods and can relocate large amounts of sediment and debris in a short period of time.

D’Arcy is part of an international research programme called StRATEGy (Surface processes, Tectonics and Georesources: The Andean foreland basin of Argentina), which looks into how past and present climate change makes a mark on the terrain of the Argentine Andes, among other topics.

This research is essential for understanding and predicting how human-caused climate change will alter weather patterns and impact surface processes (such as how quickly sediments are eroded and transported across landscapes), according to D’Arcy. Having a better understanding of these surface processes and their sensitivity to the climate could help scientists better inform the public about how to prepare for natural hazards, such as flooding, erosion and landslides.

D’Arcy notes that it’s also important to assess how climate and weather trends will impact the sedimentary record, since it is one of the only physical records that scientists can use to examine how the Earth’s surface has change through time.

“North-western Argentina is a fascinating place to study how climate change affects surface processes, because it has experienced pronounced and abrupt changes in hydroclimate through time,” said D’Arcy. Their research has found that even subtle changes in the region’s climate have produced large changes to the surface environment, impacting how rivers take shape and how sediments move.

For example, while the Sierra de Aconquija is a semi-arid environment today, more than 12,000 years ago it used to be much wetter as a result of global climate changes. In fact, back then the mountain range was covered in glaciers and many of the basins were filled with lakes.

“It’s really important that we understand how different landscapes function and how they react to changes in climate. When we look at places like the southern Central Andes in Argentina, we find that the landscape records interesting signatures of ancient climate changes in Earth’s past. However, one of the big questions we still don’t have a good answer to, is how important are these very intense but rare storms for shaping landscapes and creating the sedimentary record from the geological past,” said D’Arcy.

By Olivia Trani, EGU Communications Officer

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/.