GeoLog

Biogeosciences

Imaggeo on Mondays: Emerald Moss

Imaggeo on Mondays: Emerald Moss

The high peaks of the Tien Shan Range, one of the biggest and largest mountain ranges of Central Asia, conjure up images of snowcapped peaks, rugged terrains and inhospitable conditions. Yet, if you are prepared to look a little further, the foothills of these towering peaks are a safe haven for life. Bulat Zubairov, a researcher at Humboldt University, takes us on a journey of discovery to the Ile-Alatau National Park in today’s Imaggeo on Mondays post.

This photo was taken in the Ile-Alatau National Park, approximately at this point: 43° 9’31.81″N, 77° 5’47.36″E. The National Park is located on the northern slopes of Ile Alatau (Zailiysky Alatau) mountain range, which is a part of the Tien Shan Range and it is a main recreation zone for people who live in Almaty (the biggest city in Kazakhstan).

The photo was taken in a small watershed – an area or ridge of land which separates two bodies of water – where a small river flows. The upstream section of the watershed dries up periodically over the summer periods.

Reflecting the rich fauna and flora of the Ile-Alatau National Park, more than 100 species of mosses can be found in this area in a wooded zone. They play a significant role in regulation of water balance of the region, preventing soil erosion, supporting special types of biocenosis and promoting biodiversity conservation. Being one of the indicators of ecosystem condition, mosses also play a key role in monitoring and assessment of current changes in ecology of the region, especially taking into account ever-growing anthropogenic pressures. All this shows the relevance of efforts aimed at researching of such a beautiful and such important part of nature as mosses.

By Bulat Zubairov, PhD student at Humboldt University in Berlin

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/.

 

Geosciences Column: Three hundred years probing the deep seas

Patagonia Blues, Credit: Agathe Lisé-Pronovost (distributed via imaggeo.egu.eu)

Patagonia Blues, Credit: Agathe Lisé-Pronovost (distributed via imaggeo.egu.eu)

The depths of the deep blue have fascinated explorers, scientists and humanity for centuries. And is it any wonder? 71% of the Earth’s surface is covered by oceans teaming with riches, from unique forms of life to precious metals.Even today, there are vast regions of the ocean floors that remain unexplored and of which we know very little about. Some might argue the oceans are the last unexplored frontier on the planet.

To quote Steinar Ellefmo, an Associate Professor at NTNU’s Department of Geology and Mineral Resources Engineering, “We actually know more about the moon than the seafloor.”

The divisions of the worlds oceans. Attribution: K. Aainsqatsi, distributed via Wikipedia.org

The divisions of the worlds oceans. Attribution: K. Aainsqatsi, distributed via Wikipedia.org. Click to enlarge.

The oceans are divided into zones according to depth, temperature and how much light those depths receive. The cold and dark waters of the twilight zone and beyond continue to be the focus of much attention and fascination today. But the pursuit of understanding the ocean deep is not new; it dates back at least 400 years, if not longer.

Reconstructing the historical records of the origins of the exploration of the ocean depths is not always easy. Hampered by incomplete recording of data, poor cross referencing between studies and limited value attributed to the findings made by non-scientific sea endeavours such as fishing, historical accounts can be piecemeal. A recent paper, published in the open access journal Biogeosciences, aims to address some of these inconsistencies, as well as setting the record straight on an age-old historical misrepresentation.

How deep are the oceans and seas?

The first scientific records of attempts to measure ocean depth in the bathyal zone (defined by Gage and Tyler as depths below 200m), date back to 1521: Magellan, a Portuguese explorer who organised the first Spanish expedition to the East Indies, unsuccessfully tried to sound the ocean bottom between two pacific coral islands. It wasn’t until the 18th century that the quest for understanding the ocean floor took off in earnest.

Expedition records show that a number of 18th century explorers were, allegedly, able to sound ocean depths up to 1950m (the John Ross expedition to the Northwest Passage of the Arctic). We now know that the depths of those soundings are around half that of the depths published and likely never exceeded 1100m.

An encounter between British Royal Navy expedition, led by John Ross, and Inuit people on Baffin Bay, Greenland. The artist John Sacheuse (sometimes spelled Sackhouse) was an Inuit who acted as interpreter for Ross’s party.

An encounter between British Royal Navy expedition, led by John Ross, and Inuit people on Baffin Bay, Greenland. The artist John Sacheuse (sometimes spelled Sackhouse) was an Inuit who acted as interpreter for Ross’s party.

The problem arose from the technique employed: a line and plummet was allowed to sink to the ocean bottom and the final length of the line recorded, but divergences between the apparent and true depths plagued measurements throughout the 18th and 19th centuries. For instance, The James Clark Ross expedition (1839 -1843), sounded the ocean depth east of Brazil at 8400m, but these depths are never encounter in the region. It wasn’t until dredging became possible, and common, place that depth measurements and sampling of the sea bed saw an improvement.

Life in the bathyal zone and beyond

The aims of taking measurements of the depth of the oceans were twofold: early explorers not only wanted to know how far down our oceans extend, but also whether the waters beyond where light can penetrate could sustain life.

French naturalist François Péron proposed that the sea beds were covered by eternal ice and so the deep waters of the oceans would be unable to sustain life. On theoretical grounds, British geologist Henry de la Beche, agreed with Péron’s concept of lifeless deep ocean waters. But it was the work of naturalist Edward Forbes during the mid-1800s which really cemented the notion of an azoic layer in the oceans. While involved in sea-dredging expeditions around The British Isles and the Aegean Sea, Forbes noticed that life became increasingly sparse with greater water depth and developed the theory that ocean waters were devoid of life at depths in excess of 550m.

Basket star - Gorgonocephalus arcticus (Leach, 1819) (from Koehler 1909, pl. 9; as Gorgonocephalus agassizi; Stimpson, 1854). This is the species that was caught during the John Ross expedition.

Basket star – Gorgonocephalus arcticus (Leach, 1819) (from Koehler 1909, pl. 9; as Gorgonocephalus agassizi; Stimpson, 1854). This is the species that was caught during the John Ross expedition. From Etter and Hess, 2015. Click to enlarge.

Contrary to popular belief, the earliest recovery of deep water life was not that of the famous basket star – a branched arm, sometimes medusa-like, sea star – by John Ross in 1818. The first published record is significantly older. Specimens of upper bathyal stalked crinoid (Cenocrinus asterius) were brought up by fishing lines in the Caribbean, with specimens reaching Europe in 1761 and 1762. However, the depths at which they had been recovered were never recorded. Deep-sea fish were also recovered from the Azores, Madeira, northern Spain, Sicily and Antillean islands, but often found in shallow waters or as dead specimens floating near shore.

Cenocrinus asterius (Linné, 1767) (from Guettard, 1761, pl. 8; as “Palmier marin”). This was the first modern stalked crinoid that was described.

Cenocrinus asterius (Linné, 1767) (from Guettard, 1761, pl. 8; as “Palmier marin”). This was the first modern stalked crinoid that was described.  From Etter and Hess, 2015. Click to enlarge.

The peculiar appearance, especially in the case of the stalked crinoids, and lack of detailed records as to what depths they’d been recovered from, meant that studies of these specimens focused on their potential to be ‘living fossils’, rather than geographical distribution within the water column. Even John Ross’, now famous, basket star was neglected from much of the early 19th century literature. Not only that, the issues with accurately ascertaining the depths of soundings and the belief that organisms became entangled higher up in the water column, recovery of specimens via this method was considered far less reliable than dredging.

Had the records of earlier soundings been accurately logged and all discoveries portrayed in the literature of the time, would Forbes’ theory of a lifeless deep ocean been debunked sooner? As well as correcting the long established notion that John Ross’ basket star was the first record of deep water life, the findings of the Biogeosciences review paper highlight the importance of not uncritically following previously published synthesis of historical literature.

 

By Laura Roberts Artal, EGU Communications Officer.

 

References

Etter, W. and Hess, H.: Reviews and syntheses: the first records of deep-sea fauna – a correction and discussion, Biogeosciences, 12, 6453-6462, doi:10.5194/bg-12-6453-2015, 2015.

Gage, J. D. and Tyler, P. A.: Deep-Sea Biology: a Natural History of Organisms at the Deep-Sea Floor, Cambridge University Press, Cambridge, UK, 504 pp., 1991.

Imaggeo on Mondays: Man-made landscape

Imaggeo on Mondays: Man-made landscape

The landscape of the Mersey Estuary in Liverpool Bay is ever changing; it offers the opportunity to observe the changing geomorphology of a river estuary which is closely linked to a very urban and man-made landscape. For more on this unique setting, read today’s Imaggeo on Mondays post brought to you by Maria Burguet Marimon.

This picture was taken at Crosby beach, which is located just at the beginning of the Mersey Estuary in the Liverpool Bay. The current Crosby beach dates back in the beginning to the 20th century, in which the stabilization process of the sand was carried out.

It is important to remark that, during the first half of the 20th century, the estuary underwent a significant period of morphological change. Changes to the ebb and flood tide hydrodynamics in Liverpool Bay, caused by the construction of training walls in the outer estuary, resulted in large-scale movement of sediment into the inner estuary, increasing intertidal area and reducing the estuary volume from 745 Mm3 to 680 Mm3 (Thomas, 2000; Thomas et al., 2002). Since this time, a new equilibrium appears to have been reached and the rate of sediment movement into the estuary has slowed (Halcrow, 2010).

In 2007, following a meeting with the local government, Sefton Council,  sculptures made by Sir Antony Gormley were placed along a stretch of Crosby beach in an art exhibition known as Another Place. A total of 100 cast-iron sculptures were placed facing towards the sea. The idea of the exhibition is to show the statues at different stages: rising from the sand near the promenade to standing at the water’s edge and finally submerging into the sea. It is as if the statues are leaving us willingly but with a tinge of sadness or suffering. Each sculpture faces towards Burbo Bank Offshore Wind Farm, looking for a brighter and more ecological future.

By Dr. Maria Burguet Marimon, researcher at the University of Valencia.

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/.

The best of Imaggeo in 2015: in pictures

The best of Imaggeo in 2015: in pictures

Last year we prepared a round-up blog post of our favourite Imaggeo pictures, including header images from across our social media channels and Immageo on Mondays blog posts of 2014. This year, we want YOU to pick the best Imaggeo pictures of 2015, so we compiled an album on our Facebook page, which you can still see here, and asked you to cast your votes and pick your top images of 2015.

From the causes of colourful hydrovolcanism, to the stunning sedimentary layers of the Grand Canyon, through to the icy worlds of Svaalbard and southern Argentina, images from Imaggeo, the EGU’s open access geosciences image repository, have given us some stunning views of the geoscience of Planet Earth and beyond. In this post, we highlight the best images of 2015 as voted by our Facebook followers.

Of course, these are only a few of the very special images we highlighted in 2015, but take a look at our image repository, Imaggeo, for many other spectacular geo-themed pictures, including the winning images of the 2015 Photo Contest. The competition will be running again this year, so if you’ve got a flare for photography or have managed to capture a unique field work moment, consider uploading your images to Imaggeo and entering the 2016 Photo Contest.

Different degrees of oxidation during hydrovolcanism, followed by varying erosion rates on Lanzarote produce brilliant colour contrasts in the partially eroded cinder cone at El Golfo. Algae in the lagoon add their own colour contrast, whilst volcanic bedding and different degrees of welding in the cliff create interesting patterns.

 Grand Canyon . Credit: Credit: Paulina Cwik (distributed via imaggeo.egu.eu)

Grand Canyon . Credit: Credit: Paulina Cwik (distributed via imaggeo.egu.eu)

The Grand Canyon is 446 km long, up to 29 km wide and attains a depth of over a mile 1,800 meters. Nearly two billion years of Earth’s geological history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted. This image was submitted to imaggeo as part of the 2015 photo competition and theme of the EGU 2015 General Assembly, A Voyage Through Scales.

Water reflection in Svalbard. Credit: Fabien Darrouzet (distributed via imaggeo.egu.eu)

Water reflection in Svalbard. Credit: Fabien Darrouzet (distributed via imaggeo.egu.eu)

Svalbard is dominated by glaciers (60% of all the surface), which are important indicators of global warming and can reveal possible answers as to what the climate was like up to several hundred thousand years ago. The glaciers are studied and analysed by scientists in order to better observe and understand the consequences of the global warming on Earth.

Waved rocks of Antelope slot canyon - Page, Arizona by Frederik Tack (distributed via imaggeo.egu.eu).

Waved rocks of Antelope slot canyon – Page, Arizona by Frederik Tack (distributed via imaggeo.egu.eu).

Antelope slot canyon is located on Navajo land east of Page, Arizona. The Navajo name for Upper Antelope Canyon is Tsé bighánílíní, which means “the place where water runs through rocks.”
Antelope Canyon was formed by erosion of Navajo Sandstone, primarily due to flash flooding and secondarily due to other sub-aerial processes. Rainwater runs into the extensive basin above the slot canyon sections, picking up speed and sand as it rushes into the narrow passageways. Over time the passageways eroded away, making the corridors deeper and smoothing hard edges in such a way as to form characteristic ‘flowing’ shapes in the rock.

 Just passing Just passing. Credit: Camille Clerc (distributed via imaggeo.egu.eu)

Just passing. Credit: Camille Clerc (distributed via imaggeo.egu.eu)

An archeological site near Illulissat, Western Greenland On the back ground 10 000 years old frozen water floats aside precambrian gneisses.

Sarez lake, born from an earthquake. Credit: Alexander Osadchiev (distributed via imaggeo.egu.eu)

Sarez lake, born from an earthquake. Credit: Alexander Osadchiev (distributed via imaggeo.egu.eu)

Beautiful Sarez lake was born in 1911 in Pamir Mountains. A landslide dam blocked the river valley after an earthquake and a blue-water lake appeared at more than 3000 m over sea level. However this beauty is dangerous: local seismicity can destroy the unstable dam and the following flood will be catastrophic for thousands Tajik, Afghan, and Uzbek people living near Mugrab, Panj and Amu Darya rivers below the lake.

Badlands national park, South Dakota, USA. Credit: Iain Willis (distributed via imaggeo.egu.eu)

Badlands national park, South Dakota, USA. Credit: Iain Willis (distributed via imaggeo.egu.eu)

Layer upon layer of sand, clay and silt, cemented together over time to form the sedimentary units of the Badlands National Park in South Dakota, USA. The sediments, delivered by rivers and streams that criss-crossed the landscape, accumulated over a period of millions of years, ranging from the late Cretaceous Period (67 to 75 million years ago) throughout to the Oligocene Epoch (26 to 34 million years ago). Interbedded greyish volcanic ash layers, sandstones deposited in ancient river channels, red fossil soils (palaeosols), and black muds deposited in shallow prehistoric seas are testament to an ever changing landscape.

Late Holocene Fever. Credit: Christian Massari (distributed via imaggeo.egu.eu)

Late Holocene Fever. Credit: Christian Massari (distributed via imaggeo.egu.eu)

Mountain glaciers are known for their high sensitivity to climate change. The ablation process depends directly on the energy balance at the surface where the processes of accumulation and ablation manifest the strict connection between glaciers and climate. In a recent interview in the Gaurdian, Bernard Francou, a famous French glaciologist, has explained that the glacier depletion in the Andes region has increased dramatically in the second half of the 20th century, especially after 1976 and in recent decades the glacier recession moved at a rate unprecedented for at least the last three centuries with a loss estimated between 35% and 50% of their area and volume. The picture shows a huge fall of an ice block of the Perito Moreno glacier, one of the most studied glaciers for its apparent insensitivity to the recent global warming.

 Nærøyfjord: The world’s most narrow fjord . Credit: Sarah Connors (distributed via imaggeo.egu.eu)

Nærøyfjord: The world’s most narrow fjord . Credit: Sarah Connors (distributed via imaggeo.egu.eu)

Feast your eyes on this Scandinavia scenic shot by Sarah Connors, the EGU Policy Fellow. While visiting Norway, Sarah, took a trip along the world famous fjords and was able to snap the epic beauty of this glacier shaped landscape. To find out more about how she captured the shot and the forces of nature which formed this region, be sure to delve into this Imaggeo on Mondays post.

The August 2015 header images was this stunning image by Kurt Stuewe, which shows the complex geology of the Helvetic Nappes of Switzerland. You can learn more about the tectonic history of The Alps by reading this blog post on the EGU Blogs.

 (A)Rising Stone. Credit: Marcus Herrmann (distributed via imaggeo.egu.eu)

(A)Rising Stone. Credit: Marcus Herrmann (distributed via imaggeo.egu.eu)

The September 2015 header images completes your picks of the best images of 2015. (A)Rising Stone by Marcus Herrmann,  pictures a chain of rocks that are part of the Schrammsteine—a long, rugged group of rocks in the Elbe Sandstone Mountains located in Saxon Switzerland, Germany.

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/.

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