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

aseline navigation antennae which are exposed to ice below the keel of the ship. Any
damage by ice floes would cause severe problems for further "Victor 6000" dives. Indeed,
some hours later we entered a large field of drifting ice floes which initiated some other
activities onboard – nearly everywhere people were taking pictures. However, ice of this
thickness is no problem for the vessel – without any special effort "Polarstern" passed
through the ice to reach the next position. The deployment and recovery of winch
operated gears at starbord side is also something like routine operation for the crew.
Saturday morning we intended to release one of our lander systems which were deployed
in April this year at 2500 m water depth. After sending the acoustic release command to
both of the releasers we waited for about 50 minutes that the system appears at the sea
surface. But the instrument did not ascend and some of us immediately thought about our
Scottish colleagues and the fate of their lander. But having a Remotely Operated Vehicle
with us we decided to spend during one of the following days some hours to check the
situation and the reason of this malfunction at the seafloor. However, shortly later our
schedule was suddenly completely different – ice was again drifting towards our position
so we decided to leave the area heading to the southeasterly position of the lander which
was one nautical mile away. After arrival at the seafloor – the lander was clearly visible at
a distance of 200 m in the forward looking sonar image – we could observe that the
lander was still standing at the seafloor although both relasers were. A slight push with
one of „Victor’s“ manipulator arms was sufficient enough and the lander started ascending
to the surface.
After termination of the time and energy consuming icebreaking on Sunday evening the
27 th of July we continued with station work at a more southern location. This sudden
change in our programme did lead to another night for many of the scientists on the
working deck and their laboratories. In the morning of the 28 th we released another
mooring like the one we recovered at the early beginning of this cruise leg. Because the
top floater unit was only 200 metres below the sea level the expected time of arrival at the
surface was only some minutes after the release code was transmitted but nothing
happened. Therefore, a rubber boat was launched to try the release procedure again at a
certain distance to "Polarstern". Surface vessels produce some underwater noise by their
own sonar systems, the propellers and thrusters which might cause that the release
command becomes not properly transmitted. However, soon after sending the command
in this way the orange top unit appeared at the surface and the 2400 metres long mooring
was succesfully recovered. Monday afternoon we reached our next location where the
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