After one and a half years in the Antarctic the research vessel Polarstern is expected back in its home port on 13 April.
Apart from the crew and scientists on board, there are lots of data, samples and animals from the Southern Ocean that will soon be examined more closely in the laboratories of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI).
They stem from the area of the Filchner-Ronne Ice Shelf in the very south of the Weddell Sea, where scientists conducted research on sea ice, oceanic currents and the biocoenoses on the last Antarctic cruise leg of the expedition.
Polarstern covered over 64,000 nautical miles in the past 18 months, which corresponds to about 120,000 kilometres and thus three times the circumference of the Earth at the equator. However, the icebreaker sailed through these tropical regions only on the way there and back. The main research area was the Antarctic Weddell Sea. The last expedition prior to the return to Bremerhaven again took the vessel to the very south of Antarctica, to the marine region off the Filchner-Ronne Ice Shelf.
“Even in the Antarctic summer this area is not easily accessible and we had to struggle with very difficult ice conditions,” reports Dr. Rainer Knust, head of the expedition and biologist at the Alfred Wegener Institute. He coordinated a multidisciplinary team from eleven countries on board that conducted investigations on sea ice physics, hydrography and biology.
In close consultation with the captain, Knust laid down the work programme according to the ice conditions. The sea ice physicists were thus delighted about large ice floes on which they were able to place their measuring buoys. The latter measure whether an ice floe is growing or thawing and how quickly and in what direction it is drifting. The installed measuring buoys remain on the ice floes and transmit their data via satellite to the Alfred Wegener Institute in Bremerhaven.
The oceanographers were dependent on gaps in the ice to make use of their devices. They were able to conduct extensive oceanographic measurements of water depth, salinity, temperature and oceanic currents in the research area. In addition to these measurements directly on board, they recovered long-term moorings and deployed new ones. They record oceanographic measurements over a period of more than two years. In this way it is possible to continuously measure changes in salinity and temperature of the seawater. The objective of this work is to record and monitor the very cold melt water plume from the Filchner-Ronne Ice Shelf and its mixing with warmer water from the deeper Weddell Sea.
The work of the oceanographers is supported by Weddell Seals equipped with sensors and transmitters during the expedition. They not only supply measurements on diving behaviour during their dives, but also data on the salinity and water temperature under the ice that cannot be obtained otherwise. These data, too, are transmitted to AWI via satellite. The initial results on the biocoenoses in this still extensively unexplored region show that settlement and species diversity on the seafloor are closely connected with the ice cover and hydrography. Wherever very cold water flows out or in areas that are covered with sea ice for a very long time, species diversity and settlement density are considerably lower than in open regions that are not as greatly influenced by glacier runoff.
“Earlier findings concerning the unexpected occurrence of elephant seals on the northern shelf slope of the Filchner Trench gave the impetus to study in more detail the previously only presumed connection between hydrographic conditions and increased food supply for seals in the course of our expedition with Polarstern,” reports Knust. Prior to RV Polarstern, AWI’s research aircraft Polar 6 was also in operation on the edge of the Filchner-Ronne Ice Shelf in order to record the number of seals from the air. Using Polarstern’s on-board helicopters, biologists also undertook aerial counts. Their first impression before detailed evaluation appears to substantiate the hypothesis that there is indeed a connection between seal numbers and oceanographic conditions.
The Filchner-Ronne Ice Shelf is the second largest ice shelf in Antarctica. Coupled ocean-atmosphere model calculations at AWI indicate that dramatic changes with 20-fold higher melting rates can be expected there at the end of this century. “This expedition is the first of a series of further Polarstern voyages aimed at gaining an understanding of the actual state of the Filchner-Ronne Ice Shelf system and measuring the water masses off and under the ice shelf. Then we will compare them to the little historical data available and can then check the calculated models,” says the head of the hydrographic team on board, Dr. Michael Schröder from AWI. The future expeditions in this region will also be carried out on a multidisciplinary basis in order to examine the connection between ice, seawater and biology.
Polarstern will undergo scheduled maintenance and repair work at the Lloyd shipyard in the coming weeks before the Arctic season begins in mid-May.
Notes for Editors:
We will be glad to provide you with video material on the expedition on request. Please find printable images at http://www.awi.de/en/news/press_releases/.
Your contact persons are Dr. Rainer Knust (tel.: 0049 471 4831-1709, e-mail: Rainer.Knust(at)awi.de) and Dr. Folke Mehrtens, Dept. of Communications and Media Relations (tel.: 0049 471 4831-2007; e-mail: Folke.Mehrtens(at)awi.de).
Follow the Alfred Wegener Institute on Twitter and Facebook. In this way you will receive all current news as well as information on brief everyday stories about life at the institute.
The Alfred Wegener Institute conducts research in the Arctic, Antarctic and oceans of the high and mid-latitudes. It coordinates polar research in Germany and provides major infrastructure to the international scientific community, such as the research icebreaker Polarstern and stations in the Arctic and Antarctica. The Alfred Wegener Institute is one of the 18 research centres of the Helmholtz Association, the largest scientific organisation in Germany.
Ralf Röchert | idw - Informationsdienst Wissenschaft
New plate adds plot twist to ancient tectonic tale
15.08.2017 | Rice University
Global warming will leave different fingerprints on global subtropical anticyclones
14.08.2017 | Institute of Atmospheric Physics, Chinese Academy of Sciences
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).
The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
16.08.2017 | Physics and Astronomy
16.08.2017 | Materials Sciences
16.08.2017 | Interdisciplinary Research