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Biogeosciences

Imaggeo on Mondays: Iceland’s original birch forest

Imaggeo on Mondays: Iceland’s original birch forest

Iceland is a country of dramatically rugged landscapes. The region is home to sweeping valleys and mountain ranges, dotted with lava fields, large glaciers, hot springs and impressive waterfalls.

The territory is also notoriously treeless. As of 2016, forests only made up 1.9 percent of Iceland, according to the Icelandic Forest Service. However, about a thousand years ago the country’s landscape was far more vegetated, and remnants of Iceland’s original woodlands still exist today.

It is a common misconception that Iceland is too cold to sustain a forest. “On the contrary, it has been observed that, at the time of human settlement, birch woods and scrubs have covered large parts of Iceland,” said Marco Cavalli, a researcher at the Research Institute for Geo-Hydrological Protection in Italy and the photographer of today’s featured image. In fact, Iceland’s fossil evidence suggests that, before human settlement, 25-40 percent of the island was dominated by woodlands and thickets.

When humans migrated to the island about 1100 years ago, much of Iceland’s natural forests were chopped down to make way for fields and pastures. In the centuries following human settlement, intensive sheep grazing and volcanic eruptions prevented forests from regenerating. By 1950, less than one percent of the country was covered by trees.

Iceland’s vegetation-devoid state presents an environmental problem to local Icelanders, since the lack of trees, combined with the island’s volcanic activity, has left the land vulnerable to severe soil erosion. Since the soil conditions prevent vegetation from taking root, erosion has limited farming and grazing efforts. Iceland’s loose soil and strong winds are also responsible for damaging sandstorms.

Soil conservation and forestry services have made substantial efforts to repopulate the Icelandic environment with trees, just about doubling Iceland’s tree cover since the mid-20th century. However, there is still a long road ahead to reach the Icelandic Forest Service’s goal to see 12 percent of Iceland afforested by 2100.

This picture was taken by Cavalli while on a field trip in Rangárvellir, a southern region of Iceland near Gunnarsholt, the headquarters of the Soil Conservation Service of Iceland (SCSI). The workshop focused on the area’s severe degradation from both human activities and natural causes, and efforts to restore the ecosystem.

During the workshop he spotted this particular grove of dwarf birch trees. “I was impressed to see a small remnant patch of the Icelandic original birch forest resisting all these adverse conditions,” said Cavalli. “I would say this is a good example of nature fighting to survive.”

References

Forestry in a Treeless Land, Icelandic Forest Service

Changes in vegetation cover from the time of Iceland’s settlement, Icelandic Institute of Natural History

Vikings Razed the Forests. Can Iceland Regrow Them?, The New York Times

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: Catch of the day – what seabirds can tell us about the marine environment

GeoSciences Column: Catch of the day – what seabirds can tell us about the marine environment

Off the coast of Germany, a male northern gannet (for ease, we’ll call him Pete) soars above the cold waters of the North Sea. He’s on the hunt for a shoal of fish. Some 40km due south east, Pete’s mate and chick await, patiently, for him to return to the nest with a belly full of food.

Glints of silver just below the waves; the fish have arrived.

Pete readies himself.

Body rigid, wings tucked in close – but not so close that he can’t steer himself – he dives toward the water at a break-neck speed, hitting almost 100 km per hour. Just as he is about to hit the water, Pete folds his wings, tight, against his body. He pierces the water; straight as an arrow, fast as a bullet, and makes his catch.

The first of the day.

He’ll continue fishing for the next 8 to 10 hours.

As he does so, a tiny logger weighing no more than 48 g, will continually track Pete’s position and with every dive, the temperature of the sea water.

Why equip birds with sensors?

The physical properties of the oceans, such as water temperature, play an important role in determining where organisms are found in the vastness of the oceans. Life tends to concentrate in regions where there are temperature changes, be that as waters get deeper or across large horizontal distances.

Sea surface temperatures also reveal vital information about the global climate system, as they help scientists understand how the oceans are connected to the atmosphere. The data are used in weather forecasts and simulations of how the Earth’s atmosphere changes over time.

By mounting light-weight loggers on diving mammals (it needn’t be only birds, seals and penguins are good candidates too), scientists can learn a lot from the animal’s behaviour, while at the same time collecting data about the physical properties of the oceans.

That is why a German research team, led by Stefan Garthe of the Research & Technology Centre (FTZ) at Kiel University, has been tagging and monitoring the behaviour of a colony of northern gannets breeding on the German island of Heligoland. As a top marine predator, changes in the foraging behaviour of gannets can indicate changes in food resources, often linked to variations in the marine environment.

Flying northern gannets with a Bird Solar GPS logger attached to the tail feathers. Photo: K. Borkenhagen. From Garthe S., et al. 2017.

Their work is part of a larger project called The Coastal Observing System for Northern and Arctic Seas, or COSYNA for short, which aims to better understand the complex interdisciplinary processes of northern seas and the Arctic coasts in a changing environment.

The German Bight

The waters of the northern seas and Arctic coasts are governed by a large range of natural processes and variables, such as wind, sea surface temperature and tides. In addition, the North Sea in particular, is heavily used for human activities: from shipping, to tourism, through to exploitation (and exploration) of food resources, energy and raw materials – making it of huge economic value and importance.

But it is precisely this heavy human activity which is contributing to change and disruptions in the region. Scientists know that the biochemistry, food webs, ecosystems and species of the North Sea are being altered. However, the causes of the change aren’t well quantified or understood and their consequences poorly defined. This means mitigating and adapting to the changes is proving hard for scientists and policy-makers alike.

Where progress and nature collide

In an area so heavily influenced by anthropogenic activities, it’s not unlikely that observed changes to the properties of the waters of the North Sea and the German Bight (where Heligoland is located) are driven, to some extent, by human actions.

Since 2008, 12 offshore wind farms have become operational in the German Bight and a further five are under construction; 15 more have been given building consent too. However, what impact (if any) wind farms have on seabirds is a hotly debated topic. Their effect on the hydrodynamics, biogeochemistry and biology of the North Sea is also poorly understood.

To unravel some of these questions, Garthe and his team tracked the movements of three individual gannets near existing wind farms in the North Sea. To find out their exact position, a GPS (mounted on the bird’s tail) was used and the flight tracks plotted on a map which also displayed the wind farms of the German Bight.

Overlap of flight patterns for the three northern gannets shown with the locations of wind farms in the German Bight. From Garthe S., et al. 2017.

Their results, published in the EGU’s open access journal Ocean Science, show that all three birds largely avoided the three wind farms just north of Heligoland. Though they visited sporadically, more often than not, the gannets flew around wind farms which also happened to be further away from their breeding grounds.

The team will now use the data acquired, which is of a much higher resolution than what has been available before, to understand how wind farms in the North Sea are affecting long-term seabird behaviour.

By Laura Roberts Artal, EGU Communications Officer.

References and further reading

Garthe, S., Peschko, V., Kubetzki, U., and Corman, A.-M.: Seabirds as samplers of the marine environment – a case study of northern gannets, Ocean Sci., 13, 337-347, https://doi.org/10.5194/os-13-337-2017, 2017.

Baschek, B., Schroeder, F., Brix, H., Riethmüller, R., Badewien, T. H., Breitbach, G., Brügge, B., Colijn, F., Doerffer, R., Eschenbach, C., Friedrich, J., Fischer, P., Garthe, S., Horstmann, J., Krasemann, H., Metfies, K., Merckelbach, L., Ohle, N., Petersen, W., Pröfrock, D., Röttgers, R., Schlüter, M., Schulz, J., Schulz-Stellenfleth, J., Stanev, E., Staneva, J., Winter, C., Wirtz, K., Wollschläger, J., Zielinski, O., and Ziemer, F.: The Coastal Observing System for Northern and Arctic Seas (COSYNA), Ocean Sci., 13, 379-410, https://doi.org/10.5194/os-13-379-2017, 2017.

Why do scientists measure sea surface temperature? (NOAA)

Scientists are putting seals to work to gather ocean current data (PRI)

Daunt, F., Peters, G., Scott, B., Grémillet, D., and Wanless, S.: Rapid-response recorders reveal interplay between marine physics and seabird behaviour, Mar. Ecol.-Prog. Ser., 255, 283–288, 2003.

Grémillet, D., Lewis, S., Drapeau, L., van der Lingen, C. D.,Huggett, J. A., Coetzee, J. C., Verheye, H. M., Daunt, F.,Wanless, S., and Ryan, P. G.: Spatial match–mismatch in the Benguela upwelling zone: should we expect chlorophyll and sea-surface temperature to predict marine predator distributions?, J. Appl. Ecol., 45, 610–621, 2008.

Wilson, R. P., Grémillet, D., Syder, J., Kierspel, M. A. M., Garthe, S., Weimerskirch, H., Schäfer-Neth, C., Scolaro, J. A., Bost, C.- A., Plötz, J., and Nel, D.: Remote-sensing systems and seabirds: their use, abuse and potential for measuring marine environmental variables, Mar. Ecol.-Prog. Ser., 228, 241–261, 2002.

Imaggeo on Mondays: The invaluable role of soil dwellers

Imaggeo on Mondays: The invaluable role of soil dwellers

That soils are vital to secure our future supplies of water, food, as well as aiding adaptation to climate change and sustaining the planet’s biosphere is a subject we’ve featured on the blog as recently as the summer. That’s because never have humans been more out of touch with the vital importance of this natural resource.

Inhabiting among soil particles thrives an even less familiar, but equally important, ecosystem: rhizosphere microbes. Despite their tiny size these microorganisms play an important role in large-scale soil processes. This is particularly true in forested areas where there are strong interactions between plants (including trees, which we’ll focus on in this post), rhizosphere microbes and soil.

Let’s zoom in to the rhizosphere: the area which intimately surrounds plat roots and is home to soil microbes and minerals. It is also a hotbed of biogeochemical of activity. Minerals are weathered and plant and animal residues are transformed into soil organic matter (SOM), all that happening in a small, temporally transient zone of steep geochemical gradients.

The processes involved are complex and more and more, below-ground microbial communities face major challenges brought about by climate change. Higher temperatures and altered precipitation patterns mean the ecosystems are under threat from increased droughts and wild fire activity.

The problem is that scientists don’t fully understand how soil microbiomes are affected by these disturbances. How are their function and dynamics affected by the changing environment?

Let’s zoom out and head to the Central Cascades, USA; land of peaks as high as 4,392 m (Mt. Rainier), glacial-carved lakes and mountain valleys. Most of the range’s lower and middle elevations are covered with temperate coniferous forest (those made up of trees which produce cones and needles). In forests, it’s the rhizosphere microbes, fungi and soils which control mineral weathering and the processes which dictate the formation of SOM. This makes the forests of the Central Cascades the perfect laboratory to try and unravel some of the questions surrounding how soil microbiomes might be affected by a changing climate.

To answer this difficult question, electron microscopy is being used as a research tool for imaging and analyses of processes in environmental microbiology and biogeochemistry. Today’s imaggeo on Monday’s image was acquired by helium ion microscopy (Orion, Zeiss) at the Environmental Molecular Sciences Laboratory at the Pacific Northwest National Laboratory in Richland, WA. The image shows a few members of a diverse microbial community in ponderosa pine forest soil ecosystem in the Washington State portion of Central Cascades, USA.

By Laura Roberts, EGU Communications Officer and Alice C. Dohnalkova, senior research scientist at the Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory.

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: Three coloured pools

Imaggeo on Mondays: Three coloured pools

With the Imaggeo Photo Contest opening last week, what better than feature one of the 2015 competition finalists as this week’s Imaggeo on Mondays image. In this post, Irene Angeluccetti, author of the photograph, writes about the threatened ecosystem of Mono Lake. If you’ve been inspired by Irene’s photograph, why not entre the photo contest for your chance to win a free registration to the General Assembly in 2017? You can find out more by reading this blog post.

On a brief stop on the road from the Yosemite park to Las Vegas, we got hooked by some postcards depicting the nearby Mono Lake. We decided immediately to make a quick detour to visit the Natural Reserve surrounding the lake. Although noon wouldn’t provide the best light over the lake, we spent an hour wandering among the towers of the South Tufa area.

The alkaline Mono Lake waters, with a pH of 10 and far more salty than the ocean, are home to crowds of alkali flies and brine shrimps. These in turn are food for dozens of different waterbird species.

Mono Lake’s unique ecosystem has long been threatened by a constant decrease in water level due to water diversion. A dramatic water level drop has been observed since its tributaries started being diverted to meet the need of the Los Angeles growing water demand since 1941 on. By 1978 the lake water levels had dropped by almost half of its original volume, spurring the creation ofcitizens committee which started to take care of the future of the lake. The effort of the committee, in protecting Mono Lake, has led to the partial restoration of the original water volume. However periods of extreme drought still threaten this fragile ecosystem.

Western USA is facing one of the most severe droughts on record. In particular, California is entering the fourth year of a drought that is creating an extremely parched landscape. An effective drought monitoring is essential to plan response and recovery actions. This is especially true in the case of low-income countries prone to agricultural droughts and subsequent famine crisis.

By Irene Angeluccetti, researcher at ITHACA – Information Technology for Humanitarian Assistance, Cooperation and Action

If you pre-register for the 2016 General Assembly (Vienna, 17 – 22 April), you can take part in our annual photo competition! From 1 February up until 1 March, 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/.