GeoLog

Biogeosciences

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/.

Imaggeo on Mondays: Patterns in the peatland

Imaggeo on Mondays: Patterns in the peatland

This magnificent pattern is the result of hundreds and hundreds of years of evolution. In this structured minerotrophic peatland in Northern Quebec (Canada), which can also be called a string fen or aapa mire, the green peat ridges (or strings) alternate with water-filled hollows (or flarks). Often flarks are replaced by ponds, which vary in number and size. This pattern of strings and flarks (or ponds) runs perpendicular to the flow of ground water.

Many theories exist to explain the dynamics of this pattern; however, we still do not know the mechanism responsible. Almost all of the present theories suggest that the movement of water could be a major driver of the landscape’s features. The permafrost and frost action, the gradual down-slope slipping, and expansion of peat, the merging of hollows, and fire outbreaks are also considered to be potential factors. Further research is going on to deeply understand the complex relation between abiotic and biotic factors influencing how the string fens take shape.

Vegetation in string fens differs between strings and flarks. Strings are dominated by sedges like Carex exilis, Trichophorum cespitosum, Eriophorum angustifolium, and dwarf birches (Betula glandulosa). On the other hand, flarks or ponds are dominated by Menyanthes trifoliata (also known as bogbean), depending on the level of the water within the ground. The peat moss Sphagnum subfulvum is found on strings while a different species of moss Sphagnum majus can be found on floating mats, at the margin of ponds.

This type of peatland is abundant in the boreal regions of the world, and its predominance can be explained by cooler weather conditions, that limit Sphagnum growth and foster greater surface water flow, especially when the snow melts in the spring.

I encountered this beauty on a field trip during summer of 2016 when I was looking for fens burned by natural wildfires. Unfortunately (or not) this one did not burn, even though all the forests at the margin of the peatland burned pretty heavily. Indeed, the ground of the burned forests was covered by Polytrichum strictum, a pioneer moss known to colonize burned forests or peatland soils (look for the apple green vegetation in the bottom of the photograph).

By Mélina Guêné-Nanchen, Laval University, Québec, Canada

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: Using volcanoes to study carbon emissions’ long-term environmental effect

Geosciences Column: Using volcanoes to study carbon emissions’ long-term environmental effect

In a world where carbon dioxide levels are rapidly rising, how do you study the long-term effect of carbon emissions?

To answer this question, some scientists have turned to Mammoth Mountain, a volcano in California that’s been releasing carbon dioxide for years. Recently, a team of researchers found that this volcanic ecosystem could give clues to how plants respond to elevated levels of carbon dioxide over long periods of time. The scientists suggest that studying carbon-emitting volcanoes could give us a deeper understanding on how climate change will influence terrestrial ecosystems through the decades. The results of their study were published last month in EGU’s open access journal Biogeosciences.

Carbon emissions reached a record high in 2018, as fossil-fuel use contributed roughly 37.1 billion tonnes of carbon dioxide to the atmosphere. Emissions are expected to increase globally if left unabated, and ecologists have been trying to better understand how this trend will impact plant ecology. One popular technique, which involves exposing environments to increased levels of carbon dioxide, has been used since the 1990s to study climate change’s impact.

The method, also known as the Free-Air Carbon dioxide Enrichment (FACE) experiment, has offered valuable insight into this matter, but can only give a short-term perspective. As a result, it’s been more challenging for scientists to study the long-term impact that emissions have on plant communities and ecosystems, according to the new study.

FACE facilities, such as the Nevada Desert FACE Facility, creates 21st century atmospheric conditions in an otherwise natural environment. Credit: National Nuclear Security Administration / Nevada Site Office via Wikimedia Commons

Carbon-emitting volcanoes, on the other hand, are often well-studied systems and have been known to emit carbon dioxide for decades to even centuries. For example, experts have been collecting data on gas emissions from Mammoth Mountain, a lava dome complex in eastern California, for almost twenty years. The volcano releases carbon dioxide at high concentrations through faults and fissures on the mountainside, subsequently leaving its forest environment exposed to the emissions. In short, the volcanic ecosystem essentially acts like a natural FACE experiment site.

“This is where long-term localized emissions from volcanic [carbon dioxide] can play a game-changing role in how to assess the long-term [carbon dioxide] effect on ecosystems,” wrote the authors in their published study. Research with longer study periods would also allow scientists to assess climate change’s effect on long-term ecosystem dynamics, including plant acclimation and species dominance shifts.

Through this exploratory study, the researchers involved sought to better understand whether the long-term ecological response to carbon-emitting volcanoes is actually representative to the ecological impact of increased atmospheric carbon dioxide.

Remotely sensed imagery acquired over Mammoth Mountain, showing (a) maps of soil CO2 flux simulated based on accumulation chamber measurements, shown overlaid on aerial RGB image, (b) above-ground biomass (c) evapotranspiration, and (d) normalized difference vegetation index (NDVI). Credit: K. Cawse-Nicholson et al.

To do so, the scientists analysed characteristics of the forest ecosystem situated on the Mammoth Mountain volcano. With the help of airborne remote-sensing tools, the team measured several ecological variables, including the forest’s canopy greenness, height and nitrogen concentrations, evapotranspiration, and biomass. Additionally they examined the carbon dioxide fluxes within actively degassing areas on Mammoth Mountain.

They used all this data to model the structure, composition, and function of the volcano’s forest, as well as model how the ecosystem changes when exposed to increased carbon emissions. Their results revealed that the carbon dioxide fluxes from Mammoth Mountain’s soil were correlated to many of the ecological variables analysed. Additionally, the researchers discovered that parts of the observed environmental impact of the volcano’s emissions were consistent with outcomes from past FACE experiments.  

Given the results, the study suggests that these kind of volcanic systems could work as natural test environments for long-term climate research. “This methodology can be applied to any site that is exposed to elevated [carbon dioxide],” the researchers wrote. Given that some plant communities have been exposed to volcanic emissions for hundreds of years, this method could help paint a more comprehensive picture of our future environment as Earth’s climate changes.

By Olivia Trani, EGU Communications Officer

References

Cawse-Nicholson, K., Fisher, J. B., Famiglietti, C. A., Braverman, A., Schwandner, F. M., Lewicki, J. L., Townsend, P. A., Schimel, D. S., Pavlick, R., Bormann, K. J., Ferraz, A., Kang, E. L., Ma, P., Bogue, R. R., Youmans, T., and Pieri, D. C.: Ecosystem responses to elevated CO2 using airborne remote sensing at Mammoth Mountain, California, Biogeosciences, 15, 7403-7418, https://doi.org/10.5194/bg-15-7403-2018, 2018.

Imaggeo on Mondays: The best of imaggeo in 2018

Imaggeo on Mondays: The best of imaggeo in 2018

Imaggeo, our open access image repository, is packed with beautiful images showcasing the best of the Earth, space and planetary sciences. Throughout the year we use the photographs submitted to the repository to illustrate our social media and blog posts.

For the past few years we’ve celebrated the end of the year by rounding-up some of the best Imaggeo images. But it’s no easy task to pick which of the featured images are the best! Instead, we turned the job over to you!  We compiled a Facebook album which included all the images we’ve used  as header images across our social media channels and on Imaggeo on Mondays blog post in 2018 an asked you to vote for your favourites.

Today’s blog post rounds-up the best 12 images of Imaggeo in 2018, as chosen by you, our readers.

Of course, these are only a few of the very special images we highlighted in 2018, but take a look at our image repository, Imaggeo, for many other spectacular geo-themed pictures, including the winning images of the 2018 Photo Contest. The competition will be running again this year, so if you’ve got a flair for photography or have managed to capture a unique field work moment, consider uploading your images to Imaggeo and entering the 2019 Photo Competition.

A view of the southern edge of the Ladebakte mountain in the Sarek national park in north Sweden. At this place the rivers Rahpajaka and Sarvesjaka meet to form the biggest river of the Sarek national park, the Rahpaädno. The rivers are fed by glaciers and carry a lot of rock material which lead to a distinct sedimentation and a fascinating river delta for which the Sarek park laying west of the Kungsleden hiking trail is famous.

 

Melt ponds. Credit: Michael Tjernström (distributed via imaggeo.egu.eu)

The February 2018 header image used across our social media channels. The photos features ponds of melted snow on top of sea ice in summer. The photo was taken from the Swedish icebreaker Oden during the “Arctic Summer Cloud Ocean Study” in 2008 as part of the International Polar Year.

 

Karstification in Chabahar Beach, IRAN. Credit: Reza Derakhshani (distributed via imaggeo.egu.eu)

The June 2018 header image used for our social media channels. The photo was taken on the Northern coast of the Oman Sea, where the subduction of Oman’s oceanic plate under the continental plate of Iran is taking place.

 

River in a Charoite Schist. Credit: Bernardo Cesare (distributed via imaggeo.egu.eu)

A polarized light photomicrograph of a thin section of a charoite-bearing schist. Charoite is a rare silicate found only at one location in Yakutia, Russia. For its beautiful and uncommon purple color it is used as a semi-precious stone in jewelry.

Under the microscope charoite-bearing rocks give an overall feeling of movement, with charoite forming fibrous mats that swirl and fold as a result of deformation during metamorphism. It may be difficult to conceive, but these microstructures tell us that solid rocks can flow!

 

Refuge in a cloudscape. Credit: Julien Seguinot (distributed via imaggeo.egu.eu)

The action of glaciers combined with the structure of the rock to form this little platform, probably once a small lake enclosed between a moraine at the mountain side and the ice in the valley.

Now it has become a green haven in the mountain landscape, a perfect place for an alp. In the Alps, stratus clouds opening up on autumn mornings often create gorgeous light display.

 

Antarctic Fur Seal and columnar basalt Credit: Etienne Pauthenet (distributed via imaggeo.egu.eu).

This female fur seal is sitting on hexagonal columns of basalt rock, that can be found in Pointe Suzanne at the extreme East of the Kerguelen Islands, near Antarctica. This photo was the November 2018 header image for our social media channels.

 

Silent swamp predator. Credit: Nikita Churilin (distributed via imaggeo.egu.eu).

A macro shot of a Drosera rotundifolia modified sundew leaf waiting for an insect at swamp Krugloe. This photo was the January 2018 header image and one of the finalists in the 2017 Imaggeo Photo Competition.

 

Once there was a road…the clay wall. Credit: Chiara Arrighi (distributed via imaggeo.egu.eu)

The badlands valley of Civita di Bagnoregio is a hidden natural gem in the province of Viterbo, Italy, just 100 kilometres from Rome. Pictured here is the ‘wall,’ one of the valley’s most peculiar features, where you can even find the wooden structural remains of a trail used for agricultural purposes in the 19th and 20th centuries.

 

New life on ancient rock. Credit: Gerrit de Rooij (distributed via imaggeo.egu.eu).

“After two days of canooing in the rain on lake Juvuln in the westen part of the middle of Sweden, the weather finally improved in the evening, just before we reached the small, unnamed, uninhabited but blueberry-rich island on which this picture was taken. The wind was nearly gone, and the ragged clouds were the remainder of the heavier daytime cloud cover,” said Gerrit de Rooij, who took this photograph and provided some information about the picture, which features some of the oldest rocks in the world but is bursting with new life, in this blog post.

 

Cordillera de la Sal. Credit: Martin Mergili (distributed via imaggeo.egu.eu)

The photograph shows the Valle de la Luna, part of the amazing Cordillera de la Sal mountain range in northern Chile. Rising only 200 metres above the basin of the Salar de Atacama salt flat, the ridges of the Cordillera de la Sal represent a strongly folded sequence of clastic sediments and evapourites (salt can be seen in the left portion of the image), with interspersed volcanic material.

 

Robberg Peninsula – a home of seals. Credit: Elizaveta Kovaleva (distributed via imaggeo.egu.eu).

“This picture is taken from the Robberg Peninsula, one of the most beautiful places, and definitely one of my favorite places in South Africa. The Peninsula forms the Robberg Nature Reserve and is situated close to the Plettenberg Bay on the picturesque Garden Route. “Rob” in Dutch means “seal”, so the name of the Peninsula is translated as “the seal mountain”. This name was given to the landmark by the early Dutch mariners, who observed large colonies of these noisy and restless animals on the rocky cliffs of the Peninsula,” said Elizaveta Kovaleva in this blog post.

 

The great jump of the Tequendama. Credit: Maria Cristina Arenas Bautista (distributed via imaggeo.egu.eu)

Tequendama fall is a natural waterfall of Colombia. This blog post highlights a Colombian myth about the origins of the waterfall, which is tied to a real climate event.

 

If you pre-register for the 2019 General Assembly (Vienna, 07 – 12 April), you can take part in our annual photo competition! From 15 January up until 15 February, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.