GeoLog

imaggeo on mondays

Imaggeo on Mondays: Arctic cottongrass in Svalbard

Imaggeo on Mondays: Arctic cottongrass in Svalbard

In the High Arctic, where vegetation is limited in height, cottongrass stands out as some of the tallest plant species around.

This photo shows a wispy white patch of Arctic cottongrass growing amongst other tundra vegetation in the Advent river floodplain of Adventdalen, a valley on the Norwegian archipelago island Svalbard.

Svalbard is of particular scientific interest as it is a relatively warm region for its high latitude. This is due to the North Atlantic Ocean, which transports heat from lower latitudes to Svalbard’s shores.

The photo was taken in September 2014, towards the end of the region’s growing season. In the background, you can see that the season’s first snow had already blanketed the valley’s neighboring mountain tops.

Cottongrass generally loves wet conditions and scientists sometimes even use this plant genus (Eriophorum) as an indicator of the ground’s fluctuating water level, especially in areas that begin to develop peat, an accumulation of more of less decomposed plant material in wet environments. The waters feeding this region’s wetland come from melted snow and ice travelling down the adjacent mountains and floodwater from the Advent river, which is primarily meltwater fed.

Arctic cottongrass also can exchange gases with their underground environment through their roots and even have been shown to alter the local carbon budget of regions where they grow. It is therefore a very important species to account for when studying permafrost carbon dynamics.

Gunnar Mallon, currently a teaching fellow at the University of Sheffield (UK), took this photo while on a fieldwork expedition together with Andy Hodson, a glaciology professor at the University Centre in Svalbard, for the LowPerm project.

The LowPerm project aimed to understand how nutrients are transported within permafrost landscapes in Norway and Russia and how that may affect the production of greenhouse gases, such as carbon dioxide (CO2) and methane (CH4). The study brought together scientists from the UK, Norway, Denmark and Russia and results from the extensive field and laboratory work are currently being analysed and made ready for publication.

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: The breath of our Earth

Imaggeo on Mondays: The breath of our Earth

This picture was taken in the Myvatn geothermal area in southeast Iceland. Seeing the geothermal steam vent in this area while the temperature was -22 degrees Celsius is the best experience in Myvatn. The difference between Iceland’s cold ambient temperature and the released heat from inside the Earth is a really stunning event to see.

Iceland is situated in the middle of two tectonic plates (the Eurasian and North American plates) that, through their movement, have led to more than a hundred active and inactive volcanoes in this country. Due to the region’s high volcanic activity and shallow magma chambers, the temperature below Iceland’s surface is generally higher than that of continental areas without volcanoes. These conditions are responsible for the country’s high production of geothermal energy.

This heat can reach the surface in one of two ways. First, heat can naturally escape from the heart of Earth through cracks on the Earth’s surface itself. Second, geothermal powerplants can insert pipes far below the Earth’s surface to capture this heat.

Iceland is known for its geothermal spas, like the famous Blue Lagoon,  but additionally, Icelanders use geothermal energy as their main source of heating; in winter, almost 100 percent of the nation’s heating comes from geothermal energy. In the country’s capital Reykjavik, much of the city’s main roads are heated by this source, keeping the streets free from ice and snow. Geothermal energy also accounts for about 25 percent of the island’s electricity.

How is geothermal energy produced? As a heating source, geothermal power plants use a heat exchanger, a pipe that converts the hot water inside the earth into heat. It is then distributed within the steam pipe to residential areas. As an electricity source, power plants capture steam or hot water from geothermal areas to drive electricity generators. The machines convert the heat into electricity, which is then shared with Icelandic neighborhoods.

Because of its investment in a renewable energy source, Iceland is well known as a global leader in sustainability.

By Handriyanti Diah Puspitarini, University of Padova, Italy

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: Hints of an eruption

Imaggeo on Mondays: Hints of an eruption

The photograph shows water that accumulated in a depression on the ice surface of Vatnajökull glacier in southeastern Iceland. This 700m wide and 30m deep depression [1], scientifically called an ‘ice cauldron’, is surrounded by circular crevasses on the ice surface and is located on the glacier tongue Dyngjujökull, an outlet glacier of Vatnajökull.

The photo was taken on 4 June 2016, less than 22 months after the Holuhraun eruption, which started on 29 August 2014 in the flood plain north of the Dyngjujökull glacier and this depression. The lava flow field that formed in the eruption was the largest Iceland has seen in 200 years, covering 84km2 [2] equal to the total size of Manhattan .

A number of geologic processes occurred leading up the Holuhraun eruption. For example, preceding the volcanic event, a kilometre-wide area surrounding the Bárðarbunga volcano, the source of the eruption, experienced deformation. Additionally, elevated and migrating seismicity at three to eight km beneath the glacier was observed for nearly two weeks before the eruption [3]. At the same time, seven cauldrons, like the one in this photo, were detected on the ice surface (a second water filled depression is visible in the upper right corner of the photo). They are interpreted as indicators for subglacial eruptions, since these cauldrons usually form when geothermal or volcanic activity induces ice melt at the bottom of a glacier [4].

Fracturing of the Earth’s crust led up to a small subglacial eruption at the base of the ice beneath the photographed depression on 3 September 2014. This fracturing was further suggested as the source of long-lasting ground vibrations (called volcanic tremor) [5].

My colleagues and I studied the signals that preceded and accompanied the Holuhraun eruption using GPS instruments, satellites and seismic ground vibrations recorded by an array of seismometers [2, 5]. The research was conducted through a collaboration between University College Dublin and Dublin Institute for Advanced Studies in Ireland, the Icelandic Meteorological Office and University of Iceland in Iceland, and the GeoForschungsZentrum in Germany.

The FP7-funded FutureVolc project financed the above mentioned research and further research on early-warning of eruptions and other natural hazards such as sub-glacial floods.

By Eva Eibl, researcher at the GeoForschungsZentrum

Thanks go to www.volcanoheli.is who organised this trip.

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: River in a charoite schist

Imaggeo on Mondays: River in a charoite schist

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.

Due to the variable orientation with respect to the polarized light the charoite may exhibit different interference colors. It may be difficult to conceive, but these microstructures tell us that solid rocks can flow! Width of view: 5,4 mm.

Description by Bernardo Cesare, 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/.