News from the CSD

02.04.017: AWI Scientific divers investigated the growth of cold-water corals in a naturally acidified Patagonian fjord.

The rising CO2 levels in the atmosphere are predicted to change seawater chemistry and lower the aragonite saturation state, with negative consequences particularly for animals building up calcium carbonate skeletons such as cold-water corals. The Chilean Fjord Comau offers a unique natural laboratory, with conditions from aragonite-supersaturated waters near the surface to under saturated waters at depth. Our research revealed that the cold-water coral Desmophyllum dianthus even thrives below the aragonite saturation horizon, indicating an adaptation to acidified conditions. Because coral growth demands energy, we hypothesize that a good food supply provides the energy to maintain growth in acidified waters (lower pH-values of the seawater).

The third-part project (BMBF and CONICYT) “Plankton- And cold-water COral ecology in the Comau fjord (PACOC)” involves observational and experimental studies on the ecology of the cold-water coral Desmophyllum dianthus and ability to cope with global CO2 rise. In January/February 2017 a research team of AWI, University Austral de Chile and the Huinay Field Station carried out an expedition to Comau Fjord.

Previously test corals of the species Desmophyllum dianthus had been chiselled from the vertical rock faces by scientific divers and brought to the laboratory, where they had been glued on plastic screws, labelled, photographed and stained. Furthermore the mass had been determined with a fine balance. The corals were attached on hand made coral holders, produced in the AWI workshop and installed in the sampling depth (20m). In order to analyse the possible influence of acidified conditions on growth, test corals were cross-transplanted within the seven stations along the natural pH-gradient of the fjord. In order to have a control some corals were installed at the place of origin.

During the present austral summer expedition (after three months of exposure) test corals were de-attached and analysed for growth in the laboratory before they had been re-installed at the sites again. Furthermore the diving scientists exchanged temperature loggers. In order to describe the food supply and feeding impact by the corals, plankton nets were operated by scientific divers along a horizontal transect close to the coral wall and two meters off the wall. The data is currently analysed in Bremerhaven. The team is looking forward to the next expedition, taking place in austral autumn 2017.

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14.02.2017: Ny-Ålesund dive season 2017 successfully opened.

The AWI opened its research diving season 2017 at the polar research station Ny Ålesund by arrival of the scientific diving team on the 27.01.2017. Five different projects were scheduled for this first expedition. For three “macro algae” projects (KOL-06), fresh algae and long term exposure samples had to be recovered and the status of underwater long term experiments had to be checked and photographically documented. Furthermore, the status of the AWIPEV underwater observatory had to be assessed after an iceberg hit the system at the 15. Jan. 2017 - and in case of damage -  the respective repair works should be performed under water. Besides, routine maintenance and calibration procedures were scheduled for the AWIPEV-FerryBox, which is part of the underwater observatory project KOL07.

The first days started in truly arctic conditions. -25°C (-40° with wind chill factor) made diving very challenging with respect to freezing equipment on the boat and the human factor, when staying more than 2h outside outsind on the water. After one week, the temperatures increased to unexpected positive degrees and intense rainfall started. This turned all roads and places in Ny-Ålesund into an almost perfect skating rink and stopped all regular flight movements from and to Longyearbyen for almost one week. Parts of the scientific crew therefore arrived by helicopter while others left Ny-Ålesund, other collegues could not arrive at all.

Nevertheless, all samplings were performed as scheduled and the maintenance work under water could be finished successfully within a total of 18 “night”-dives.

The AWI dive team

Interested in the AWIPEV underwater observatory at Ny Alesund work? Please visit the project page here

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07.12.2016: Pressemeldung - Forscher entwickeln Unterwasser-Observatorium

Die Weiten des Meeres und dessen zeitweise harschen Bedingungen stellen Meeresforscher häufig vor schwierige Situationen. In der Nordsee nahe Helgoland haben Wissenschaftler des Thünen-Instituts für Seefischerei, des Alfred-Wegener-Instituts (AWI) und des Helmholtz-Zentrums Geesthacht (HZG) jetzt ein außergewöhnliches Gerät ausgebracht: ein optisch-akustisches Unterwasser-Observatorium....(mehr)

09.12.2016: Artikel in der Bergedorfer Zeitung zum Unterwasserobservatorium Helgoland.

 

 

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14.11.2016: Successful year 2016 at Svalbard for the AWI dive-group: Three dive-missions completed

The year 2016 comes to an end and the AWI dive-group looks back on three busy and successful dive-missions in Svalbard's Kongsjord on 79°N.

The group opened the diving-season in the middle of winter in February 2016 when three AWI divers together with a team of technicians from 4H Jena and from the French cooperation partners "Laboratoire d'Océanographie Villefranche" travelled to Ny Ålesund. Their mission during this early time of the year was the regular surface- and underwater maintenance of the "Spitsbergen Underwa­ter Observatory" (COSYNA@AWIPEV Underwater Observatory).

This observatory is located at the south shore of the Kongsfjord (West Spitsbergen) and includes various scientific instruments at land and under water. The observatory makes continuous remote controlled measurements of the main oceanographic data such as tempera­ture, salinity, oxygen, turbidity, pCO2 and others. The system also supports a permanent operating ADCP (Acoustic Doppler Current Profiler - fig. 5) for continuous current and wave measurements, a remote-controlled stereo-optical unit to assess species abundance and length-frequency distributions of the macrobi­otic commu­nity including the fish (fig. 3) and instruments from cooperating institutes (fig. 6).

The system is completed by a land based "ferry-box" system pumping seawater from the observatory's base station in 12 m water depth for further water analysis and sampling. Since this base unit including the seawater pumps and the so called under water node (the underwater supply unit for power and network - fig. 2) is operated year-round, it is heavily exposed to the harsh arctic condi­tions such as low temperatures, currents, high sedimentation and the omnipresent threat by drifting ice and icebergs. Therefore, together with the regular maintenance, the dive-team had to repair some ice caused damages and exchanged some technical parts and instruments to bring the observatory back to a 100% operating status for the upcoming season.

Even though the permanent darkness of the polar winter (fig. 1) was already replaced by some dawn light at least for a few hours per day, the divers under water had to work in almost complete darkness with underwater lights mounted to their equipment to illuminate the working area. Finally, everything went well during this first mission and even the repositioning of a 400 kg concrete anchor-block which was displaced by an ice­berg, worked out quite well in complete darkness.

Unfortunately, only few weeks after the AWI dive team left NyAlesund, another iceberg hit the underwater cable so that the communication to the underwater part of the observatory started to become critical. With the help of the AWIPEV station personal, the REMOS part of the underwater observatory (the cam­era- and profiling observation unit of the COSYNA@AWIPEV Underwater Observatory) could be "parked" safely on the seafloor. Fortunately, the land based "ferry-box" system could be still operated in an emergency mode so that the measurements of the basic hydrographic variables could be continued. Because of this damage, the AWI dive-group carried out a second mission in April to repair the underwater system and to resolve some further damages.

During this second stay, the daylight was back, the weather conditions were good and the dive locker including the dive boat were prepared within 1½ days, so that the second mission could start. For this stay, a team of three experienced divers were chosen to recover the underwater observatory system, to ex­change parts, repair pumps and bring the whole system back into operation mode within a few days.

The third dive-mission in 2016 took place in September/October for eight weeks with the overall goal to collect more scientific data and information on the polar fjord system during autumn and beginning winter. During this stay, the dive team supported a total of eight different scientific projects with seven projects, partly with own diving scientists on site which were integrated in the core dive team. The main task for most of the projects was the collection of samples such as macro algae, benthic animals or sediment cores. Furthermore, several experimental underwater set-ups had to be installed, maintenance of existing set-ups had to be carried out and long-term experiments had to be checked and evaluated. Additionally, the underwater observatory was upgraded by two new concrete fundaments carrying new light-loggers (PAR). In this regard, special thanks goes to the department "AWI technical workshop" (Erich Dunker and Matthias Littmann) which provided us, as always over the last years, with perfect scientific equippement to install and improove the under water installations at the Svalbard observatory.  

Unfortunately, unusual strong rainfall and relatively warm temperatures dominated the last time of the year 2016 so that high sedimentation-rates caused a quite bad visibility under water, which sometimes made our efficient work under water quite problematic. Nevertheless, at the end every­thing worked out, all experiments for the winter season 2016-2017 were installed and all involved parties are looking forward to the winter results in spring 2017. Altogether, during the 2016 Svalbard dive-missions, the AWI dive team did more than 120 dives in the Kongsfjord with a total of eight different divers, supporting nine scientific projects with at least four scientific institutions involved.

 

 

 

 

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29.10.2016: News from the AWIPEV Underwater observatory at 79°N.

A filmteam from the Norwegian broadcast visited the AWIPEV underwater observatory in September 2016 during our maintenance stay at NyAlesund. Please click here to go to the TV-story.

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10.01.2016: Course "European Scientific Diver - geprüfter Forschungstaucher 2016" open for application.

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20.11.2015: AWI dive expedition to the German Antarctic Station Neumayer III started

See the weekly reports in the Neumayer III Blog AtkaXpress

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18.11.2015: Field campaign of the Master student Jonas Löb successfully finished.

Since the beginning of September Jonas Löb from Oldenburg University was part of our scientific diving group to work on his Master thesis. The topic of the thesis is about the effect of feeding pressure by herbivorous animals on the depth zonation of Fucus spp. on Helgoland. Therefore 24 enclosure cages (see photo - 12 fully closed and 12 half closed) and 12 open rings were equipped with the brown algae Fucus serratus and Fucus vesiculosus and were deployed near the MarGate experimental field in a water depth of around 5m. The experiment started on the 24th of September and lasted six weeks. On November the 5th the cages and rings were successfully recovered. The comparative approach shall increase the understanding how herbivorous feeding pressure affects different algal species, if feeding pressure can restrict the lower depth limit  of F. vesiculosus compared to F. serratus and additionally, whether the exclusion of herbivorous feeding pressure increases the competitive ability of F. vesiculosus compared to F. serratus.

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07.11.2015: Field campaigns of the two Master students Gustavo Gumprich and Kristin Sprenger successfully finished.

After three months of intense field work with a lot of scientific diving in the underwater experimental field MarGate off Helgoland, the two Master students and Certified Research Divers Gustavo Gumprich and Kristin Sprenger from University Rostock have successfully finished their field work. In stratified line-transect counting in 5 m and 10 m water depth, they assessed the fish and crustacean community in the MarGate field in the month August to October. The data are now analyzed and the two theses will be submitted before Christmas. The two studies are done in the framework of the long term project „Impact of coastal defence structures (tetrapods) on demersal fish and decapod crustaceans“ at the AWI Centre for Scientific Diving.