Preface The expedition ARK XIX/3 with the German icebreaking RV ...

deep-sea research group of the AWI already worked with "Victor 6000" onboard the
French RV „L’Atalante“ in 2001. Experiments initiated two years ago were sampled during
the night.
On Wednesday the 30 th of July we started with the preparation of a rather ambitious
project: the installation of a current flume in the Arctic deep sea. Two packages of
compartments of this roughly 10 m long channel were deployed with the ship’s winch and
"Victor 6000" was subsequently send down to put them together. For one day the ROVpilots
were constantly working on this task and finally succeeded in the installation of the
first current channel in the Arctic deep-sea to simulate and create gradients at the
seafloor. Because of the shape of the flume the current speed should increase inside,
thus causing different environmental conditions for the sediment inhabiting fauna, the
settling regime for organic particles as well as alterations in exchange processes between
sediment and water. The installation of such infrastructure at great water depth is only
possible by using working class ROV’s like "Victor 6000".
During the last dive of "Victor 6000" at the central station of the long-term deep-sea
station at the beginning of the last week in July we had to recover the ROV very fast
because another drifting ice field approached. The shuttle and two scientific instruments
had to be left at the seafloor. During the following days "Polarstern" worked at other
locations, the current flume was somewhat further in the south installed, but the ice
situation was constantly evaluated according to actual satellite images provided by the
meteorological service onboard. With regard to the end of the cruise leg and the
termination of ROV operations some days in advance to ensure that everything of the
ROV system is stored before arrival in Tromsø, our last chance to recover the instruments
came on Friday. The ice was drifting further northeastward and the ROV was immediately
launched under ice-free conditions to recover the instruments and to get some final
samples.
After safe recovery of "Victor 6000" from its last dive during this expedition the final days
of our cruise leg were used to work with winch operated gears, free falling lander systems
and the deployment of moorings. In the meantime the ultra short baseline underwater
navigation antenna was also removed from the ships’s keel so that we were more flexible
in our operation between floating ice.
In the early evening of the 4 th of August all station work was completed and "Polarstern"
started to head south to Tromsø where the cruise leg ARK XIX/3 c was terminated in the
morning of August 7 th .
- 19 -