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fieldwork

Imaggeo on Mondays: The calm before the storm

Imaggeo on Mondays: The calm before the storm

The picture was taken during the 2015 research cruise HE441 in the southern German Bight, North Sea. It features the research vessel Heincke, on a remarkably calm and warm spring day, forming a seemingly steady wake.

The roughly 55 metre long FS Heincke, owned by the German federal government and operated by the Alfred Wegener Institute, provides a great platform for local studies of the North Sea shelf. Eleven scientists and students from the University of Bremen, MARUM Research Faculty, University of Kiel, and Federal Waterways Engineering and Research Institute, along with the ship’s crew formed a great team under the supervision of chief scientist Christian Winter.

On deck, different autonomous underwater observatories were waiting to be deployed. Their purpose was to measure the seabed- and hydrodynamics in a targeted area of the German Bight. The investigation of the interaction between geomorphology, sedimentology and biogeochemistry is crucial to understand the processes acting on this unique and dynamic environment. In the German Bight various stakeholders with diverse interests come together. Profound knowledge, backed by cutting edge research, helps to resolve future conflicts between use and protection of the environment.

While this photo features a tranquil day at sea, some days later the weather and wave conditions got so bad that the cruise had to be abandoned. Storm Niklas, causing wave heights of more than three metres, made deployment and recovery of the observatories too dangerous for the crew, scientists, and delicate instruments.

Despite the severe weather, the research cruise was still able to gather important data with the time made available. Schedules on research vessels are tight and optimized to fit as much high-quality measurements as possible into time slots that are depending on convenient sea (tide) and weather conditions. State-of-the-art research equipment were prepared, deployed, recovered and assessed several times during the then only 8-day long cruise. Measurements were supported by ship based seabed mapping and water column profiling. Transit times, like the one depicted, were used to prepare the different sensors and instruments for the upcoming deployment.

The rare occasion of good weather combined with idle time was utilized to take this long exposure photo. A calm sea, a stable clamp temporarily attached to a handrail, and a neutral density filter were additionally required to increase the exposure time of the camera to 13 seconds, in order to capture this picture. The long exposure time smooths all movement relative to the ship, enhancing the effect of the wake behind the Heincke vessel.

Over the course of several years, regular Heincke research cruises and the collaboration between the different institutions has led to the successful completion of research projects, with findings being published in various journals, listed below.

By Markus Benninghoff, MARUM, University of Bremen, Germany

Further reading

Ahmerkamp, S, Winter, C, Janssen, F, Kuypers, MMM and Holtappels, M (2015) The impact of bedform migration on benthic oxygen fluxes. Journal of Geophysical Research: Biogeosciences, 120(11). 2229-2242. doi:10.1002/2015JG003106

Ahmerkamp, S, Winter, C, Krämer, K, de Beer, D, Janssen, F, Friedrich, J, Kuypers, MMM and Holtappels, M (2017) Regulation of benthic oxygen fluxes in permeable sediments of the coastal ocean. Limnology and Oceanography. doi:10.1002/lno.10544

Amirshahi, SM, Kwoll, E and Winter, C (2018) Near bed suspended sediment flux by single turbulent events. Continental Shelf Research, 152. 76-86. doi:10.1016/j.csr.2017.11.005

Krämer, K and Winter, C (2016) Predicted ripple dimensions in relation to the precision of in situ measurements in the southern North Sea. Ocean Science, 12(6). 1221-1235. doi:10.5194/os-12-1221-2016

Krämer, K, Holler, P, Herbst, G, Bratek, A, Ahmerkamp, S, Neumann, A, Bartholomä, A, van Beusekom, JEE, Holtappels, M and Winter, C (2017) Abrupt emergence of a large pockmark field in the German Bight, southeastern North Sea. Scientific Reports, 7(1). doi:10.1038/s41598-017-05536-1

Oehler, T, Martinez, R, Schückel, U, Winter, C, Kröncke, I and Schlüter, M (2015) Seasonal and spatial variations of benthic oxygen and nitrogen fluxes in the Helgoland Mud Area (southern North Sea). Continental Shelf Research, 106. 118-129. doi:10.1016/j.csr.2015.06.009

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 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/.

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: Exploring ice in the deep

Imaggeo on Mondays: Exploring ice in the deep

The occurrence of sporadic permafrost in the Alps often needs challenging fieldwork in order to be investigated. Here in the high altitude karstic plateau of Mt. Canin-Kanin (2587 m asl) in the Julian Alps (southeastern European Alps) several permanent ice deposits have been recently investigated highlighting how also in such more resilient environments global warming is acting rapidly. Important portions of the underground cryosphere are actually rapidly melting, loosing valuable paleoarchives contained in the ice.

Description by Renato R. Colucci, 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: On the way to Tristan’s penguins

Imaggeo on Mondays: On the way to Tristan’s penguins

Tristan da Cunha is a remote volcanic island in the south Atlantic Ocean. In fact, it is the most remote inhabited archipelago in the world. Tristan is still volcanically active; the last time it erupted was in 1961. After the eruption, which luckily did not have any casualties, the whole population of around 260 people evacuated the island for some time, but they all returned back to the island because it was home.

I took this photo while aboard the ISOLDE research cruise associated with the GEOMAR Helmholtz Centre for Ocean Research in Germany. The ISOLDE project focuses on investigating the electromagnetic, gravimetric and seismic activity present on this little island.

There are several reasons why this area is particularly interesting for multi-disciplinary geophysical studies. First, the island is a prominent candidate for a deep-rooted hot spot. A hot spot is a volcanic region believed to be fed by mantle plumes, which bring considerable heat from deep in the Earth. Deploying ocean bottom seismometers (OBS) should help investigate the presence (or absence) of a whole-mantle plume beneath the island. Second, geophysical analysis in this region can help scientists better understand the tectonic processes involved in the extension of the South Atlantic margins and the formation of the Walvis Ridge.

In 2012, the ISOLDE (as part of the SAMPLE project) research cruise aimed to acquire a year’s worth of data on the marine electromagnetic activity, active and passive seismicity, gravity and bathymetry around Tristan da Cunha. Among others, there were 24 OBS deployed on the sea floor (around 3000-4000 m in depth). These instruments stay on the ocean bottom for one year and continuously record seismic signals.

After one year, in 2013, I joined the recovery cruise. This was my second time on a research vessel, but it was the first time I actually worked as a technical assistant on OBS.

The cruise started from Walvis Bay, a coastal town in Namibia. After a one-week transit from the harbour to the first station, we spent around seven days recovering 12 OBS around Tristan da Cunha.

The process of recovering the instruments is usually straight forward. To start, you head to the location where you first deployed the instrument, put a transducer into the water and then ping the OBS. If you get a response, you enter a code that sends an acoustic signal to release the main instrument from its steel anchor. The floating units attached to the instrument then take care of bringing the OBS back to the sea surface. Depending on the depth, it can take up to an hour until the OBS resurfaces (e.g. this is a simple calculation: 3000m deep, rising velocity of 1 m/s).

This would be a perfect recovery procedure, but you know, it rarely happens like this! After recovering half of the instruments over the course of about a week, the team got a well-deserved day off on Tristan.

Tristan da Cunha is such a small, beautiful, strange and lonely island. I was almost expecting to find a lost native tribe there, but in truth, it looked like any small town in England, with tiny gardens in front of their houses. Once we arrived at the island we had the choice between taking a touristic tour of the potato fields, where the Tristanians go in summer for holidays, or exploring the island independently.

I decided to go off to the north of the island. It was a perfect day, sunshine with no clouds in the sky, which was surprising for the South Atlantic. I wandered off past the remains of the famous 1961 eruption and the island’s own dumping place until I couldn’t go further. I arrived at a stony beach, from where I could see our ship, the M/S Merian, in the distance, anchored before the island’s coast, since our vessel was too big for Tristan’s small harbour.

I spotted the three penguins standing next to each other sun bathing. ‘Chilled guys’, I thought; and even when I drew closer to take the shot, they looked entirely relaxed and barely noticed me. It’s not like they had seen so many tourists around here! After taking the picture, I placed myself next to them (it’s surprising how smelly they are) to enjoy the view and the sun. Further down the beach, I also spotted a big mama seal and its adorable small fluffy baby. Right in front of me an orca emerged from the waters, properly trying to get to the seals. It flashed its fin before diving down again.

All in all, it was a surreal experience sitting on the remotest island on Earth surrounded by animals I usually only see in a zoo. After one wonderful day on Tristan da Cunha, we went back onboard to continue recovering the remaining OBS from the deep ocean.

By Maria Tsekhmistrenko, University of Oxford (UK)

References

SAMPLE webpage

ISOLDE project description

OBS provided by DEPAS pool in AWI

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: In-tents Icelandic sunset

Imaggeo on Mondays: In-tents Icelandic sunset

This photograph was taken at the campsite near lake Mỳvatn during a field trip to Iceland. Every year a group of students from Wageningen University travels from the Netherlands to Iceland for a weeklong excursion as part of a course on catchment hydrology. The aim of the trip is to provide students with real life examples of the processes they learned during their lectures.

After a rainy morning that day, tents and equipment were packed away as quickly as possible in order to escape the wetness. The drive took the group from the campsite in Höfn, at the foot of the Vatnajökull glacier in southeastern Iceland, along the coastal highway up north towards Myvatn. Iceland is famous for its raw and beautiful nature, with waterfalls seemingly around every corner and the imposing presence of the glaciers and volcanos in the distance.

Upon our arrival at the campsite in the evening, people begrudgingly noticed that the tents were still wet from the morning rain. The campsite was situated at the bottom of a formidable hill, which provided stunning views over the lake and landscape. Not wanting to sleep in a damp tent, a few students picked up their tents, dismantled them, went up the hill and let the evening breeze do the rest, all amid the backdrop of a stunning sunset. The desire for dry covers even outweighed the very real danger of being eaten alive by masses of midges, a known pest and hazard in these parts.

When camping there is always things that can go wrong. But for places like Iceland it is the only way to truly appreciate and experience the country’s stunning beauty and wilderness. Gazing up at the northern lights from your sleeping bag is a once-in-a-lifetime experience. While waking up in the middle of the night and having to put on boots and jacket to run to the bathroom is vexing, you might be rewarded with views of the top of the glacier that has been shrouded in clouds all day, making it seem like Zeus himself is taking a peek down from Mount Olympus to see what is going on. Iceland has to be experienced, not from a cosy hotel bed, but from a tent put up in the evening and taken down the next day. As Albert Einstein once said: “Look deep into nature, and then you will understand everything better”. Even if that means hiking up a hill and holding your tent up into the wind to dry.

By Maria Warter, PhD student at Cardiff University