The German research vessel Polarstern has returned today to Bremerhaven from the Arctic Sea. It has cruised as the first research vessel ever both the Northeast and the Northwest Passages and thereby circled the North Pole.
The third part of the research vessel's 23rd Arctic expedition, operated by the Alfred Wegener Institute in the Helmholtz Association, started its journey on August 12th in Reykjavik and ended it on October 17th in Bremerhaven.
The ship travelled a distance of 10.800 nautical miles, equivalent to 20.000 kilometres. On board were 47 researchers from 12 nations, for example from Belgium, Germany, France, Japan, Canada, Korea, the Netherlands, Russia and the USA. Because of the small ice cover, the expedition members were able to research hitherto uncharted waters. The small sea ice cover presents a cause for concern regarding climate change in the Arctic Ocean. The aim of this expedition was to gather data on the development of the geology of the Arctic area.
The researchers around cruise leader Dr. Wilfried Jokat, geophysicist at the Alfred Wegener Institute, have discovered large sliding masses close beneath the seafloor of the East-Siberian continental shelf by means of sediment-acoustic parasound measurements. "Sliding masses are witnesses of great sediment relocations which appear, for instance, when large amounts of sediments are deposited," explains Jokat. The continental slope becomes instable and sediments slide down. Such a large amount of sediments causing a shift can only have one reason: the sediments were frozen in the ice masses of the East-Siberian mainland, thawed during an interglacial and unloaded their sediments with the melt water into the ocean.
"This is a spectacular finding. Large-scale glaciations in eastern Siberia within the younger geological past of 60.000 years and older are so far unknown," explains Prof. Dr. Rüdiger Stein, geologist at the Alfred Wegener Institute. Additional acoustic (seismic) data show that the East-Siberian Shelf was covered with ice over the last three million years only during a few glacial periods.
Further investigations are necessary to confirm this finding and particularly to time the reported events chronologically. The scientists have brought material in the form of sediment cores to Bremerhaven to achieve this. 16 soil samples could be taken on a transect of 700 kilometres from the Canada Basin via the Mendeleev Ridge into the Makarov Basin. The analysis will allow for the first time to compare the glacial history of the Northern USA and Canada with Siberia and to elaborate differences and parallels in detail. Furthermore, the data from the sediment cores can deliver information on the temporal and spatial changes of ocean currents and the extent of sea ice in the central Arctic Ocean. "We expect from these investigations important new insights into the control procedures of long and short term climate changes in the Arctic," says a delighted Stein.
Another focal point of this cruise was on the geological development of the Arctic Ocean during the last 90 million years. Seismic, an acoustic measurement method, allows peeking into the deep layers under the ocean floor down to 4.000 metres depth. "The collected data show that the ocean basin between the two Arctic ridge systems, the Lomonossov and the Mendeleev Ridge, are considerably older than estimated so far. Thus, the basins in the old part of the Arctic Ocean, the Makarov and the Canada Basin, have developed at about the same," reports Jokat. "The following detachment of the Lomonossov Ridge from the East-Siberian Shelf took place 60 million years ago - not without massive changes to the environment. The data present evidence of strong relocation processes in the deep-sea sediments," continues the geophysicist. "Many model representations about the development of the Arctic Ocean must be rethought on the basis of the new data," concludes Jokat.Oceanographers regularly collect data on water temperature, density and salinity from the ship. Additionally, they brought out buoys on ice floes which autonomously conduct these measurements over one or two years. The oceanographers can thereby better understand how the water masses circulate in the Arctic Ocean. Integrated into long-term measurements, they can describe changing water temperatures and sea ice cover regarding climate change.
Biologists on board investigated the occurrence and distribution of the copepod Oithona similis in the Arctic Ocean. This small crab is an important part of the food web. It feeds, among other things, on small algae and animals and serves on its part as food for fish larvae. Another biological programme is aimed at collecting data on the distribution of birds, seals, whales and polar bears along the route. An almost continuous measurement of the seafloor and a programme for water probes rounded off the interdisciplinary scientific programme.
The measurements contribute to research within the framework of the International Polar Year, the European project DAMOCLES and the North Atlantic project of the German Federal Ministry of Education and Research. After the usual maintenance and repair work, Polarstern will leave on October 31st with the destination Cape town. There begins the Antarctic season 2008/09.
The Alfred Wegener Institute carries out research in the Arctic and Antarctic as well as in the high and mid latitude oceans. The institute coordinates German polar research and makes available to international science important infrastructure, e.g. the research icebreaker "Polarstern" and research stations in the Arctic and Antarctic. AWI is one of 15 research centres within the Helmholtz-Association, Germany's largest scientific organization.
Margarete Pauls | idw
Research sheds new light on forces that threaten sensitive coastlines
24.04.2017 | Indiana University
NASA sees the end of ex-Tropical Cyclone 02W
21.04.2017 | NASA/Goddard Space Flight Center
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
24.04.2017 | Physics and Astronomy
24.04.2017 | Materials Sciences
24.04.2017 | Life Sciences