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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/.

IGLUNA: students work towards building an icy human habitat on the Moon!

IGLUNA: students work towards building an icy human habitat on the Moon!

What does it take to build a habitat in ice on the Moon? An international group of university students and professionals is working together to provide this answer and develop a sustainable and operational habitat in lunar ice. The project is called IGLUNA and is organised by the Swiss Space Center and the European Space Agency (ESA) as the first initiative from ESA_Lab, an ESA interuniversity research platform where young professionals across Europe can work together on space projects.

Many of the participating students from Vrije Universiteit Amsterdam in the Netherlands presented their work on IGLUNA at the European Geosciences Union General Assembly in Vienna last month. Arlene Dingemans, a VU Amsterdam student and project participant, says,

At the moment, we are a pilot team, the first one working on this project, and we really hope that future teams will develop further this research and maybe, one day, we can go to the Moon!

The North Pole of the Moon where potential lunar cups would be located. Credit: NASA

Human life as we know it today, can only survive under specific environmental conditions; we need the right kind temperature, atmosphere, gravity, radiation, and access to oxygen and water to properly function. On Earth, we have all the necessary resources but as far as we know, our planet is the only place where human life can thrive. Thus, it is vital to carry out research and experiments in order to better understand how human life can be sustainable in places with harsh conditions. The Moon is our closest planetary object and the best place to investigate how life can be supported there.

As part of their project, the group will be testing an analog lunar habitat on Earth, on a glacier in Zermatt, Switzerland, under cold and harsh conditions similar to the Moon’s ice craters in the south pole.

Building a habitat in ice on the Moon also has several benefits. Firstly, water (ice) is essential for life as we know it on Earth, but it can also be used to produce oxygen and fuels. Furthermore, ice is a great insulator for cosmic and solar radiation, and it can function as a shield against micrometeorites.

The field campaign will also involve operating several different experiments that could hypothetically  be done on the moon. Operations will start operations on 17 June, lasting until 3 July; during this time the habitat will also be open to the public, allowing visitors to watch and even take part in experiments.

The entrance tunnel into the Glacier Palace in Klein Matterhorn, Zermatt, Switzerland, where the IGLUNA habitat will be constructed. Credit: Swiss Space Center (SSC) / IGLUNA

The research conducted by the VU Amsterdam team in IGLUNA will focus on geological, glaciological, and astrobiological experiments. Bernard Foing, a professor at VU Amsterdam supervising the student team, highlights: “It’s important not only to live on the Moon, but also to do something really useful. We are going to learn about the Moon, about the Earth, [and] do astronomy. Also this project is a way to exchange expertise and to learn a lot through hands-on activities.”

Marc Heemskerk, participant and student coordinator explains:

The simulation aims to prepare ourselves and humanity in the best possible way for going to the Moon and living there in a semi-permanent or permanent basis. And I really think that it’s not a question of whether we will go to the Moon, but of when we will go. So, eventually, we will have to learn how to live there and how to use local resources.

Transferring resources from the Earth to the Moon in order to build a base it is extremely expensive in terms of energy and money, hence, it is vital to use local materials, Heemskerk explains.

The cave in which the IGLUNA habitat will be constructed – 15m below the surface of the Matterhorn Glacier, Switzerland. Credit: Swiss Space Center (SSC) / IGLUNA

The construction of an operational habitat requires knowledge and skill exchange between people from different backgrounds. 20 student teams coming from 13 universities in nine countries around Europe  from multiple disciplines work together to address the challenges of building an effective structure, which one day could be fully independent and operational on the Moon.

Dieke Beentjes, a participating student emphasizes:

What is also interesting is that our research team is already multidisciplinary. We started out as a team of geologists and now we also have biologists, as biological research is different and needs different instruments – to look at DNA and life traces for example.

The scientific equipment includes cameras, a spectrometer, a microscope, telescopes, a seismometer, drones and many others.

This initiative inspires students to think about the idea of a habitat, while increasing international relationships and collaborations. Marjolein Daeter, another project participant says, “It’s more like an opportunity to get to know this world and we get help from our university and ESA to do that. It’s fun to work with different people on this.”

If you are interested about the project, you can follow the link here: https://www.spacecenter.ch/igluna/ 

By Anastasia Kokori, EGU Press Assistant

References

Benavides, T. et al.: IGLUNA – Habitat in Ice: An ESA_Lab project hosted by the SSC. Geophysical Research Abstracts, Vol. 21, EGU2019-17807, 2019 (conference abstract)

Daeter, M. and Dingemans, A.: VU Science Experiments (VUSE) for Igluna, a science showcase for a Moon ice habitat. Geophysical Research Abstracts, Vol. 21, EGU2019-17500, 2019 (conference abstract)

De Winter, B. et al.: VUSE, VU Science Experiments at Igluna, a Science Showcase for a Moon Ice Habitat. 50th Lunar and Planetary Science Conference 2019 (LPI Contrib. No. 2132) (conference abstract)

Heemskerk, M. V. et al.: IGLUNA Habitat in Ice: An ESA_Lab project hosted by the Swiss Space Center. 50th Lunar and Planetary Science Conference 2019 (LPI Contrib. No. 2132) (conference abstract)

Imaggeo on Mondays: Crowned elephant seals do citizen science

Imaggeo on Mondays: Crowned elephant seals do citizen science

In the Southern Ocean and North Pacific lives a peculiar type of elephant seal. This group acts like any other marine mammal; they dive deep into the ocean, chow down on fish, and sunbathe on the beach. However, they do all this with scientific instruments attached to their heads. While the seals carry out their usual activities, the devices collect important oceanographic data that help scientists better understand our marine environment.

The practice of tagging elephant seals to obtain data started in 2004, and today equipped seals are the largest contributors of temperature and salinity profiles below of the 60th parallel south. You can find all sorts of data that has been collected by instrumented sea creatures through the Marine Mammals Exploring the Oceans Pole to Pole database online.

The female elephant seal, pictured here at Point Suzanne on the eastern end of the Kerguelen Islands in the Southern Ocean, is a member of this unusual headgear-wearing cohort. This particular seal had been roaming the sea for several months with the device (also known as a miniature Conductivity-Temperature-Depth sensor) on her head. As the seal dove hundreds of metres below the sea surface, the instrument captured the vertical profile of the area, recording the ocean’s temperature and salinity, as well as chlorophyll a fluorescence and concentrations. When the seal resurfaced, the sensor sent the data it had accrued to scientists by satellite.

Etienne Pauthenet, a PhD student at Stockholm University who was involved in a seal tagging campaign, had a chance to snap this photo before tranquilising the seal and retrieving the tag.

Using elephant seals and other marine mammals to collect data gives scientists the opportunity to analyse remote regions of the ocean that aren’t very accessible by vehicles. Studying these parts of the world are important for gaining insight on how oceans and their inhabitants are responding to climate change, for example. With the help of data-gathering elephant seals, researchers are able to amass in situ measurements from regions that previously had been hard to reach, apply this data to oceanographic models, and make predictions on ocean climate processes.

While gathering data via elephant seals are crucial to oceanographic research, Pauthenet explains that the practice is sometimes quite difficult. “It can be complicated to find back the seal, because of the Argo satellite signal precision. The quality of the signal depends on the position of the seal, if she is lying on her back for example, or if she is still in the water.”

While on the research campaign, Pauthenet and his colleagues were stationed at a small cabin on the shore of Point Suzanne and they walked the shore every day in search of the seal, relying on location points transmitted from a VHF radio. After seven days they finally located her and removed her valuable crown. The seal was then free to go about her business, having given her contribution to the hundreds of thousands of vertical profiles collected by marine mammal citizen scientists.

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/.

GeoSciences Column: Can seismic signals help understand landslides and rockfalls?

GeoSciences Column: Can seismic signals help understand landslides and rockfalls?

From the top of a small gully in the French Alps, a 472 kg block is launched into the chasm. Every detail of it’s trajectory down the slope is scrutinised by two cameras and a network of seismometers. They zealously record every bounce, scrape and tumble – precious data in the quest to better understand landslides.

What makes landslides tick?

In 2016, fatalities caused by landslides tipped 2,250 people. The United States Geological Survey (USGS) estimates that between 25 and 50 people are killed, annually, by landslides in the United States alone. Quantifying the economic losses caused by landslides is no easy task, but the costs are known to be of economic significance.

It is paramount that the mechanisms which govern landslides are better understood in hopes that the knowledge will lead to improved risk management in the future.

But landslides and rockfalls are rarely observed in real-time. Deciphering an event, when all you have left behind is a pile of debris, is no easy task. The next best thing (if not better than!) to witnessing a landslide (from a safe distance) is having a permanent record of its movement as it travels down a slope.

Although traditionally used to study earthquakes, seismometers have now become so sophisticated they are able to detect the slightest ground movements; whether they come from deep within the bowels of the planet or are triggered by events at the surface. For some year’s now they have been an invaluable tool in detecting mass movements (an all-encompassing term for the movement of bed rock, rock debris, soil, or mud down a slope) across the globe.

More recently, processing recorded seismic signals triggered by large catastrophic events has not only allowed to identify when and where they occurred, but also their force, how quickly they travel, gain speed and their direction of movement.

This approach gives only a limited amount of data for scientists to work with. After all, large, catastrophic, mass movements represent only a fraction of the landslide and rockfall events that occur worldwide. To gain a fuller understanding of landslide processes, information about the smaller events is needed too.

So, what if scientists could use a seismic signal which is generated by all mass movements, independent of their size?

The high-frequency seismic signal

A high-frequency seismic signal is generated as the individual particles, which combined make up a landslide or rockfall, bounce and tumble against the underlying layer of rock. Would it be possible to, retrospectively, find out information about the size and speed at which individual particles traveled from this seismic signal alone?

This very question is what took a team of scientists up into the valleys of the French Alps.

At a place where erosion carves gullies into lime-rich muds, the researchers set-up two video cameras and network of seismometers. They then launched a total of 28 blocks, of weights ranging from 76 to 472 kg, down a 200 m long gully and used the data acquired to reconstruct the precise trajectory of each block.

The impacts of each block on the underlying geology, as seen on camera, were plotted on a 3D representation of the terrain’s surface. From the time of impact, block flight time and trajectory, the team were able to find out the velocity at which the blocks travelled and the energy they carried.

View from (a) the first and (b) the second video cameras deployed at the bottom of the slope. The ground control points are indicated by blue points. (c) Trajectory reconstruction for block 4 on the DEM, built from lidar acquisition, superimposed on an orthophoto
of the Rioux-Bourdoux slopes. Each point indicates the position of an impact and the colour gradient represents the chronology of these impacts (blue for the first impact and red for the last one). K2 is a three-component short-period seismometer and K1, K3 and K3 are vertical-only seismometers. CMG1 is a broad-band seismometer. From Hibert, C. et al., 2017. (Click to enlarge)

As each block impacted the ground, it generated a high-frequency seismic signal, which was recorded by the seismometers. The signals were processed to see if information about the (now known) properties of the blocks could be recovered.

Following a detailed analysis, the team of scientists, who recently published their results in the EGU’s open access journal Earth Surface Dynamics, found a correlation between the amplitude (the height of the wave from it’s resting position), as well as the energy of the seismic signals and the mass and velocities of the blocks before impact. This suggests that indeed, these high-frequency seismic signal can be used to find out details about rockfall and landslide dynamics.

But much work is left to be done.

There is no doubt that the type of substrate on which the particles/blocks bounce upon play a large part in governing the dynamics of mass movements. In the case of the French Alps experiment, the underlying geology of lime-rich muds was very soft and absorbed some of the energy of the impacts. Other experiments (which didn’t use single blocks), performed in hard volcanic and metamorphic rocks, found energy absorption was lessened. To really get to the bottom of how much of a role the substrate plays, single-block, controlled release experiments, like the one described in the paper, should be performed on a variety of rock types.

At the same time, while this experiment certainly highlights a link between seismic signals and individual blocks, rockfalls and landslides are made up of hundreds of thousands of particles, all of which interact with one another as they cascade down a slope. How do these complex interactions influence the seismic signals?

By Laura Roberts Artal, EGU Communications Officer

References and resources:

Hibert, C., Malet, J.-P., Bourrier, F., Provost, F., Berger, F., Bornemann, P., Tardif, P., and Mermin, E.: Single-block rockfall dynamics inferred from seismic signal analysis, Earth Surf. Dynam., 5, 283-292, doi:10.5194/esurf-5-283-2017, 2017.

USGS FAQs: How many deaths result from landslides each year?

The human cost of landslides in 2016 by David Petley, published, 30 January 2017 in The Landslide Blog, AGU Blogosphere.

[Paywalled] Klose M., Highland L., Damm B., Terhorst B.: Industrialized Countries: Challenges, Concepts, and Case Study. In: Sassa K., Canuti P., Yin Y. (eds) Landslide Science for a Safer Geoenvironment. Springer, Cham, (2014)