Archive | July, 2012

We are moving!

13 Jul

As you can see from our updated header, from Monday 16 July 2012 onwards, we will be moving GeoLog to a new, simpler address: http://geolog.egu.eu/. The content and layout of the blog on our new page are exactly the same as on this one – only the address is changing.

If you subscribed to this blog via email, you will be automatically subscribed to the posts in the new address. If you subscribed to this blog via WordPress, please follow our new blog by clicking on the “Follow” button on the bottom right corner of the new website.

Geolog has a new URL, update your bookmarks!

Roundup of EGU Twitter Journal Club 2

13 Jul

The EGU’s Twitter Journal Club had its second virtual meeting yesterday, this time focusing on a paper from the EGU’s journal Biogeosciences, investigating the means by which microscopic life is sustained in the hostile aridity of the Atacama Desert. Read a full transcript of our discussion on our Storify page!

Vast expanse of Chile’s Atacama Desert, one of the most arid regions in the world. (source: Wikimedia)

The European Geosciences Union, through publishing house Copernicus Publications, publishes 14 peer-reviewed Open Access journalsBiogeosciences (BG, IF 3.587)  is an international scientific journal dedicated to the publication and discussion of research articles, short communications and review papers on all aspects of the interactions between the biological, chemical and physical processes in terrestrial or extraterrestrial life with the geosphere, hydrosphere and atmosphere. The objective of the journal is to cut across the boundaries of established sciences and achieve an interdisciplinary view of these interactions.

Imaggeo on Mondays: Cordillera del Paine

9 Jul

Cordillera del Paine by Martin Mergili, distributed by EGU under a Creative Commons licence.

Images such as the one above inspire scientists and nature lovers alike. This photograph, showing a Chilean landscape with elements representative of various Earth-science disciplines, is simply stunning. In a beautiful mix of shapes and colours, a quiet lake with floating icebergs appears tucked in between a roughed mountain in the background and a colourful double rainbow in the foreground.

The photographer, Martin Mergili of the University of Natural Resources and Life Sciences in Vienna, captured this inspiring scenery during a holiday trip a few years ago. The photo shows the eastern edge of the southern part of Cordillera del Paine, a “small but spectacular” mountain group in the Torres del Paine National Park, which is located in Chilean Patagonia almost 2,000 kilometres south of Santiago de Chile.

“The prominent peaks visible in the left portion of the image are the Cuernos del Paine,” Martin explains. “The rainbow in the foreground is not just decoration, it reflects the ever-changing weather patterns characteristic of that area. Even though it is located in the rainshade of the Cordillera at the edge of the semi-arid Patagonian lowlands, the westerlies bring a lot of moist air from the Pacific Ocean. The icebergs in the lake in the foreground (Lago Grey) originate from the large Glaciar Grey calving into the lake.”

More stunning images of this and other landscapes are available from Martin’s website.

Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) can submit their images to this repository. Being open access, it can be used by scientists for their presentations or publications as well as by the press. If you submit your images to imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

EGU Twitter Journal Club: Article 2

6 Jul

Time for the second edition of the EGU’s Twitter Journal Club, our interactive online discussion about a timely scientific article. Full details can be found here

This time, our article focuses on one of the most extreme environments on Earth, the Atacama Desert in Chile, and the method by which rock-dwelling microorganisms obtain their water. The Twitter discussion will take place on Thursday 12 July at 17:00 CEST (hashtag #egutjc2). Please email the EGU’s Science Communications Fellow Edvard Glücksman with further questions. Happy reading!

The Atacama Desert is one of Earth’s driest environments. (credit: Wikimedia)

Novel water source for endolithic life in the hyperarid core of the Atacama Desert
Biogeosciences, 9, 2275-2286, 2012

Abstract. The hyperarid core of the Atacama Desert, Chile, is possibly the driest and most life-limited place on Earth, yet endolithic microorganisms thrive inside halite pinnacles that are part of ancient salt flats. The existence of this microbial community in an environment that excludes any other life forms suggests biological adaptation to high salinity and desiccation stress, and indicates an alternative source of water for life other than rainfall, fog or dew. Here, we show that halite endoliths obtain liquid water through spontaneous capillary condensation at relative humidity (RH) much lower than the deliquescence RH of NaCl. We describe how this condensation could occur inside nano-pores smaller than 100 nm, in a newly characterized halite phase that is intimately associated with the endolithic aggregates. This nano-porous phase helps retain liquid water for long periods of time by preventing its evaporation even in conditions of utmost dryness. Our results explain how life has colonized and adapted to one of the most extreme environments on our planet, expanding the water activity envelope for life on Earth, and broadening the spectrum of possible habitats for life beyond our planet.

Questions to think about:
1. How would you summarise this article in a tweet?

2. The Atacama Desert is one of the driest environments on the planet. Can you think of others, and do you know of similar studies done there?

3. What is the link between the research presented here and our quest to find extraterrestrial life?

4. How could the methods presented here be improved in follow-up studies?

5. Do you see industrial applications for these findings?

Related media coverage
National Geographic Magazine
Sydney Morning Herald

The European Geosciences Union, through publishing house Copernicus Publications, publishes 14 peer-reviewed Open Access journalsBiogeosciences (BG, IF 3.587)  is an international scientific journal dedicated to the publication and discussion of research articles, short communications and review papers on all aspects of the interactions between the biological, chemical and physical processes in terrestrial or extraterrestrial life with the geosphere, hydrosphere and atmosphere. The objective of the journal is to cut across the boundaries of established sciences and achieve an interdisciplinary view of these interactions.

Geosciences column: For permafrost, (sediment) size does matter

4 Jul

In this month’s Geosciences Column, David Bressan – now a regular EGU contributor – highlights a recent result published in The Cryosphere with implications on the occurrence and preservation of alpine permafrost.

The last 150 years saw an increase of 0.8°C in the Earth’s mean global temperature. In mountain ranges like the European Alps, however, this rising trend is even more pronounced with an increase of 1.5°C in temperature observed over the same period. This rise not only accelerates the retreat of the alpine glaciers, but also causes the slow degradation of alpine permafrost – solid material with temperatures well below the freezing point of water at 0°C – and rock glaciers – lobes composed of a mixture of ice and rock debris, covered by a few meters of ice-free debris.

On a superficial glimpse, the permafrost seems relatively well isolated from superficial changes due to the cover of ice-free soil and rocks. However, measurements in the past few years have shown that the melting rate of ice inside the rock glaciers significantly increased in the last decades, which could lead to the destabilization of mountain slopes and could influence the hydrology of nearby springs.

To understand the behavior of permafrost in a warmer future it is therefore essential to understand how the material (for example different rock types) and the texture (like grain size or distribution) of the layers covering the permafrost transport heat from the warming surface into the frozen underground. Heat transfer in these layers can occur in two ways: conduction trough the rocky material or convection by mobile phases, like air or water, in the voids and pores of the material.

Scientists first investigated the site of the Murtel rock glacier, located in the mountains of the Swiss canton of Engadin, in 1970. The area has since become one of the best documented sites for mountain permafrost in the world. Permafrost occurs here below very heterogenous substrate like barren bedrock, vegetated bedrock, debris of a talus slope, fine-grained and coarse-grained debris of two rock glaciers. In a long-term project, geographer Sina Schneider and her team analyzed the temperature profiles of these different substrates, recorded in five boreholes over a period of eight years (2002–2010). The study was published last year in The Cryosphere, an open access journal of the European Geosciences Union.

Photographs of the different surfaces at the borehole locations in the investigation area, taken in summer 2009 (from Schneider et al. 2012).

The results confirmed in part previous observations, but showed also new intriguing finds. Freezing during late autumn and early winter influences significantly the temperature profile in all boreholes, as without an impermeable snow cover cold air can penetrate into the pores of the material. A dry winter with lacking or thin snow cover and rare freezing can therefore be more important for thawing permafrost than a hot summer.

Also the covering material can influence the behavior of the subsurface permafrost. Sites covered with an isolating cover of soil and vegetation showed significantly fewer fluctuations in the temperatures between winter and summer.

Borehole temperature data from 2002–2010 compared to monthly mean air temperature and snow cover. In bedrock the superficial heat (red and green colours) is conducted deep into the underground. Coarse-grained debris (like found at the talus slope or at the rock glaciers) is a relative effective insulator; however in fine-grained debris heat penetrates deep into the underground, causing thawing of permafrost (from Schneider et al. 2012).

In coarse-grained material air circulation in the voids plays a major role, cooling the underground effectively. Both in the coarse-grained debris of the talus slope and in the rock glacier no significant increase of temperatures along the contact between cover and permafrost was observed in eight years. However, it was in fine-grained material that most permafrost thawing occurred. Numerous complex processes, like water infiltration, freezing and air circulation, seem to be especially effective in the small pores of fine-grained sediments and transport heat deep into the underground.

In computer models used to calculate the changes and future distribution of permafrost and permafrost-related natural hazards the composition of the surface is often neglected – in part due the difficulties to gain detailed information in rugged mountain terrains. However the study by Schneider et al. shows that sediment type and size does matter and detailed field survey and data collection play essential parts in understanding the reactions of the hidden permafrost in a warmer climate.

By David Bressan, freelance geologist based in Italy

Teachers at Sea: Farewell Marion!

2 Jul

In the last couple of weeks, GeoLog had the pleasure to host reports from Teachers at Sea. This educational programme, co-sponsored by the European Geosciences Union (EGU) and the French Polar Insitute (IPEV), gives school teachers the opportunity to take part in oceanographic cruises with scientists. This year, Sandrine Vivier and Ana Sánchez, teachers of Biology and Geology in Rodez (France) and Madrid (Spain), respectively, together with EGU’s Education Chair Carlo Laj, joined scientists on board of the Marion Dufresne. The research vessel navigated the South China Sea where teachers worked alongside scientists in collecting marine sediments to retrieve the secrets of deep ocean circulation and understand past variations of the Asian Monsoon. This is the last post of the series. Check out previous posts here.

Report 9: Farewell Marion!

As the Marion Dufresne heads back to Singapore, the cruise enters its last few days.

The scientific team on board has been very busy updating all measurements taken, storing them in different computers, writing the final cruise reports, cleaning all the equipment used, and packing some of the instruments used to send back home.

The cores in the refrigerated container (photo by Catherine Kissel)

The cores that will be shipped to France are now stored in a refrigerated (4°C) container, ready to transit first to the Réunion Island on the Marion, and from there to France in the same container but on a different vessel. They will be delivered at the Laboratoire des Sciences du Climat et de l’Environnement (LSCE) at Gif sur Yvette near Paris in early September. The cores for Tongji University will have a shorter journey: from Singapore, where they will be disembarked, they will be shipped directly to Shanghai.

During the short seven days of coring, much work was done. We have obtained 350 meters of cored sediments, collected water samples for measuring the pH (to study ocean acidification), obtained several CTD (Conductivity/Temperature/Depth) profiles, just to mention a few of our activities.

End of the cruise party in the forum of the Marion Dufresne (photo by Ana Sanchez)

End of the cruise barbecue dinner on the rear deck (photo by Ana Sanchez)

After all the work, we have had a well-deserved ‘end of the cruise party’ at the forum and an ‘end of the cruise barbecue’ on the back deck, now clean and free from the coring equipment. We have also taken the traditional group photo of all the scientists together with the crew of the Marion Dufresne.

The team on board of the Marion Dufresne

We express our deep thanks to the French Polar Institute (IPEV) and to the European Geosciences Union (EGU) for making it possible for us to participate in this session of the Teachers at Sea programme. Many thanks to the IPEV personnel on board who were always very patient with us. Special thanks also go to Bárbara Ferreira, for editing our texts and publishing them in such an attractive blog!

Thank you also to the crew of the Marion Dufresne, particularly to Captain Lassiette and Chief Engineer Rolland.

And of course, we wish to thank all the scientists on board, especially co-chief scientists Catherine Kissel and Zhimin Jian.

The Marion Dufresne from the Zodiac raft (photo by Hélène Léau)

Long live the Marion Dufresne!

By Carlo Laj (with Sandrine Vivier and Ana Sánchez)

Imaggeo on Mondays: Kerlingarfjöll

2 Jul

Kerlingarfjöll by János Kovács, distributed by EGU under a Creative Commons licence.

Iceland, with its stunning volcanic landscapes, is one of the world’s most geologically rich countries. Kerlingarfjöll, featured in this week’s image, is a prime example of that. This Icelandic mountain range, covering an area of 150 square kilometres, formed during a volcanic eruption in the Late Pleistocene – some 100 thousand years ago.

“Kerlingarfjöll is very different to the environment around, both in shape and colour. The mountains are mostly made out of rhyolite and both dark and bright tuff, and there is also a lot of volcanic glass,”  it is explained in the  Kerlingarfjöll official website. “When Kerlingarfjoll was being created, there was a glacier over the mid highlands, and in certain places it seems that pillars of tuff reached out of the melting glacier ice. That is why there are tuff pillars with a lava top.”

The mountains are located in central Iceland, in an area of stunning natural beauty. “I had the chance to visit this beautiful country several times in the last ten years,” the photographer János Kovács, a geologist based at the University of Pécs in Hungary, says. “If anyone wants to see the real Iceland, they should rent a big 4×4 and drive through the country.”

Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) can submit their images to this repository. Being open access, it can be used by scientists for their presentations or publications as well as by the press. If you submit your images to imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.