Research vessel Polarstern returns with new findings from the Central Arctic during the 2012 ice minimum

October 10, 2012
Melt Pond sampling site; in the front: llka Peeken (MARUM/AWI), Anique Stecher, Christiane Uhlig (both AWI) and Luisa Galgani (GEOMAR), to the right: Stefan Hendricks (AWI) on bear watch (© M. Fernandez, Alfred Wegener Institute)

Polarstern is expected back from the Central Arctic expedition "IceArc" in Bremerhaven on 8 October 2012 after a good two months. 54 scientists and technicians from twelve different countries conducted research on the retreat of the sea ice and the consequences for the Arctic Ocean and its ecosystems over a period of two months in the High North. A number of new technologies were used for to film and photograph life in and below the ice down to a depth of 4400 metres. Since its departure from Tromsø (Norway) on 2 August 2012 Polarstern has travelled some 12,000 kilometres and conducted research at 306 stations. These included nine ice stations where the ship moored to an ice floe for several days to examine the ice, the water beneath it and the bottom of the sea.

Many measurements were concerned with responses to the rapid retreat of the this summer. The researchers determined that the thick multiyear sea ice in the area of investigation had declined further. With the so-called EM-Bird (electromagnetic sensor to record the thickness of sea ice) an area of 3,500 kilometres of sea ice was measured from a helicopter. As early as July 2012 the Siberian shelves including the Laptev Sea were free from ice, whereas in the summer of 2011 Polarstern had still encountered multiyear ice in this region. This means that the volume of ice is greatly reduced by melting. The fresh of the has increased accordingly as a result of the melting ice. "The Arctic of the future will consist of thinner sea ice which will therefore survive the summer less frequently, will drift more quickly and permit more light to penetrate the ocean. This will lead to great changes in the composition of ", says head of the expedition Prof. Dr. Antje Boetius, who manages the Helmholtz-Max-Planck Research Group for Deep-sea Ecology and Technology at the Alfred Wegener Institute.

Credit: Marcel Nicolaus, Alfred-Wegener-Institut

With a new type of under-ice trawl, the researchers headed by Dr. Hauke Flores from the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association were able for the first time to conduct large-scale investigations of the communities living directly on the lower side of the Arctic pack ice. "We had a polar cod in our net almost every time. This species is particularly adapted to life below the ice; it does not occur without ice", explained Flores on the significance of the sea ice as a habitat. The sea ice physicists from the Alfred Wegener Institute also used an under-ice robot to record the light incidence and distribution of algae on the lower side of the ice. They were able to detect the diatom Melosira artica in high concentrations also under the first-year ice in the central basin of the Arctic. These single cell algae can produce metre-long chains and form dense accumulations beneath the ice. Photos from the deep sea have shown that the algae largely dropped to the as a result of the .

According to the findings of the returning Polar researchers, the rapid changes in the Arctic were not therefore restricted to the sea surface. Atlantic water flowing into the Arctic at a depth of several hundreds had an elevated temperature and salinity which could be measured down to a depth of several thousands of metres in the Arctic Basins. Images and measurements of the bottom of the sea showed for the first time that the deep sea of the Central Arctic is not a desert, but that frequently accumulations of sea cucumbers, sponges, feather stars and sea anemones gather to feed on the sea algae.

The warm temperatures, the retreat of the ice and the greater light availability beneath the ice causes the seasonality of the Central Arctic to shift. The production and the export of algae is taking place earlier compared with previous years, as the results of annually anchored sediment traps show. As a result of the extremely thin ice cover, Polarstern was able to navigate far into the North later in the year than usual. The sea ice physicists were therefore able to collect important data at the start of the freezing period. The measurements on the new thin ice are important, because this sea ice will occur more frequently in the future.

Explore further: Higher Water Temperatures and Reduced Ice Cover In the Arctic Ocean

More information: www.geo.de/blog/geo/polarstern-expedition

Related Stories

Arctic sea ice may be at 'tipping point'

September 16, 2005

Arctic ice melting may have accelerated to a "tipping point" that will produce a vicious cycle of melting and heating, U.S. scientists say.

Winter Sea Ice Fails to Recover, Down to Record Low

April 6, 2006

Scientists at NSIDC announced that March 2006 shows the lowest Arctic winter sea ice extent since the beginning of the satellite record in 1979 (see Figures 1 and 2). Sea ice extent, or the area of ocean that is covered by ...

Is the ice in the Arctic Ocean getting thinner and thinner?

August 20, 2010

The extent of the sea ice in the Arctic will reach its annual minimum in September. Forecasts indicate that it will not be as low as in 2007, the year of the smallest area covered by sea ice since satellites started recording ...

Declining sea ice to lead to cloudier Arctic: study

March 31, 2012

Arctic sea ice has been declining over the past several decades as global climate has warmed. In fact, sea ice has declined more quickly than many models predicted, indicating that climate models may not be correctly representing ...

Annual Arctic sea ice less reflective than old ice

May 17, 2012

In the Arctic Ocean, the blanket of permanent sea ice is being progressively replaced by a transient winter cover. In recent years the extent of the northern ocean's ice cover has declined. The summer melt season is starting ...

Recommended for you

What would a tsunami in the Mediterranean look like?

August 27, 2015

A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal ...

Intensity of desert storms may affect ocean phytoplankton

August 27, 2015

Each spring, powerful dust storms in the deserts of Mongolia and northern China send thick clouds of particles into the atmosphere. Eastward winds sweep these particles as far as the Pacific, where dust ultimately settles ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.