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

The microbathymetry survey of the "Moira mounds" was successfully completed on
Saturday afternoon. Before the end of the dive a pre-site survey across the summit of the
Galway mound was carried out in order to identify and select appropriate locations for a
lander and several current metres to be deployed on Sunday morning. After deployment it
was planned to use the ROV to locate them at the seafloor and to move them to different
locations around the "Galway mound". Therefore, the module containing the multibeam
sonar was disconnected from "Victor 6000" and another module allowing sampling and
landing at the seabed was attached during the night. At the same time benthos samples
were taken using the giant box corer, a heavy grab which takes a representative square
sample of the seafloor of 50 by 50 cm. This was the first of a number of such samples
and contained living corals, sponges, crustaceans and other invertebrates. Such single
point samples will help the scientists, for example, to identify individuals observed in the
video transects and still photographs to species level.
On Sunday morning the lander and current metres were deployed using the winches of
"Polarstern". Subsequently, the ROV started to search for them which lasted less than
one hour. After location pictures, showing the environment in which the lander was
standing, were taken and the various current metres became distributed. During the night
the wind increased again and it was decided to abort the dive. The final tracks for video
surveying and mosaicking, the latter a technique were overlapping video images are
overlain by computer software to get long stripes of seafloor images, was scheduled for
Monday afternoon under the expected better weather conditions.
During the night of Sunday 8 th June and all day Monday the box corer was used for an
intensive quantitative sampling programme of preselected seabed sites. A selection of the
live material from the box corer samples was immediately transferred to aquaria and
placed in a cooled laboratory container onboard where the fauna was kept alive at about
8 °C water temperature until transfer into larger aquaria in Galway at the end of the cruise
leg. In between box corer deployments several CTD casts were executed and the 38 kHz
fisheries echosounder used to locate potential fish shoals which may aggregate above
the mounds.
Soon before midnight the "Victor 6000" was sent down to the seafloor again to continue
with the dive which had been aborted the previous day. Tuesday the 10 th of June was
fully occupied by this "Victor 6000" dive which lasted about 36 hours in total. After
deployment during the night the ROV started with a video transect at around 900 m water
depth. Flying at an altitude of about two meters above the seabed a predefined dive track
- 7 -