This Thursday, 14 June 2012, the research vessel Polarstern will leave Bremerhaven on course for the Arctic. 44 expedition participants from institutions from Germany, Belgium, USA and the United Kingdom will spend around one month at sea.
Their main study area is the Fram Strait between Spitsbergen and Greenland where they will conduct long-term oceanographic measurements. At the end of June the second part of the expedition will travel to the “AWI Hausgarten” for two weeks with a biological focus. In August the research icebreaker will then travel to the Central Arctic after which it is expected back in Bremerhaven at the beginning of October.
The Fram Strait is the only deep sea water connection between the Arctic Ocean and the Atlantic. How much water is exchanged between these two seas and what heat and salt transport is associated with this? How is the water in the Arctic Ocean altered which flows in the East to the North and in the West to the South? Which masses of water flow how quickly through the Fram Strait? To record these basic parameters, temperature, salinity and oxygen content are determined precisely with sensitive sensors.
“The aim of our research is to quantify the water masses and heat exchange between the North Polar Sea and the Northern Atlantic and circulation in the Fram Strait“, says Dr. Agnieszka Beszczynska-Möller. The oceanographer at the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association will be leading this first part of the expedition. The measurements are an important puzzle piece for understanding the complex correlations between ocean, sea ice and atmosphere in the Arctic. Other research groups from the Alfred Wegener Institute also use the long-term data for their disciplines such as for models on sea ice development.
The Polar Regions play a decisive role in the global ocean circulation, thereby influencing the global climate. Warm, high saline water flows from the Atlantic to the North. By contrast, cold, low saline surface water flows from the Arctic Ocean to the North Atlantic and on to the South. Low saline, cold deep-sea water also flows from the North Polar Sea and feeds the so-called thermohaline circulation. The flows may alter as a result of global warming which is why the researchers have been observing this region for 15 years by accurately recording the conditions in the Fram Strait and the changes from on board the Polarstern.
In addition to this annual inventory in summer, the researchers measure the flow conditions and different environmental parameters also in their absence using so-called moorings: anchor stones are placed on the sea bed to which lines are attached which are held up several hundred to thousand metres with the assistance of floats. Sensors are attached at defined water depths, which record data throughout the entire year. Variations throughout the seasons can also be recorded accurately in this way and be considered in the overall analysis. This work is embedded in an international observation network. Sea gliders supplement the measurements; these are free floating vehicles, which determine their course in open water via satellites and are orientated by acoustic signals in the case of ice cover. They therefore supplement the stationary mooring assemblies.
The two final parts of the Polarstern expedition also address questions of long-term changes in the Arctic. To the west of Spitsbergen biologists under the lead of Dr. Thomas Soltwedel primarily investigate the marine environment in the deep sea. After a stopover in Norwegian Tromsö an international team under the lead of deep-sea researcher Prof. Dr. Antje Boetius will leave for the Central Arctic around the North Pole.
After its return to Bremerhaven in October 2012, Polarstern will be got ready for the forthcoming Antarctic expedition. At the end of October the ship will then set out for one and a half year’s in the South: for the fourth time in its history, Polarstern will also be travelling Antarctic waters during polar night. On the way to the Neumayer Station III, on 9 December 2012, the German research icebreaker will be celebrating the 30th anniversary of its commissioning.
Subsea World News Staff , June 14, 2012; Image: AWI