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

6000" was still at depth "Polarstern" would have been hampered in search manoeuvres
for the shuttle in the fog. The meteorologist onboard predicted better conditions for the
next morning so the risk to loose the shuttle after release was not taken under these
circumstances.
During the final days of the second cruise leg of the expedition ARK XIX/3 the water
column above the HMMV was investigated with almost all instruments we had onboard.
The CTD and water sampler, for example, were additionally equipped with a methane
sensor and a camera. According to actual sonar data information we placed these
instruments in different regions, either with high methane concentration, at borders and at
such depth where no methane was acoustically detected.
Wednesday morning (16.07.2003) the last dive of "Victor 6000" during the second part of
the cruise leg ARK XIX/3 started. Twenty minutes earlier the shuttle was send down to
the seafloor – also its last launch. The shuttle was additionally equipped with a radio
beacon. Because we had to leave our area of investigation on Thursday in time we could
not risk that fog, which might have come up the next day, delays our departure. The final
dive of "Victor 6000" was again used to work with autonomous instruments. Among a
system which measures the exchange of solutes between sediment and the water column
another system measuring the current speed was used to get data on fluid and gas
release rates out of the sediment. Such data might help to estimate the amount of
methane release at the Håkon Mosby Mud Volcano.
After safe recovery of "Victor 6000" and the shuttle on Thursday the research activities
were stopped and "Polarstern" started to head northward to Longyearbyen on Svålbard,
some 400 miles away. The last hours onboard were used to get all material stowed into
the boxes and containers, final treatment of some samples, writing of the cruise report
and the closing colloquium where all working groups presented their preliminary results.
At July the 19 th the majority of scientists, technicians and all ROV pilots disembarked in
Longyearbyen (Svålbard) while other personell came onboard for the final leg ARK
XIX/3c. This leg was dedicated to work at the AWI long-term deep-sea station
"Hausgarten" at 79 ° N and 4 ° E. First long-term experiments with special emphasis on
Arctic deep-sea biodiversity and exchange processes across the sediment-water interface
were already launched during the "Polarstern" expedition PS ARK XV/1 in 1999 using
"Victor 6000" and two years later again with the ROV onboard the French RV "L'Atalante".
Sampling of long-term experiments started during both expeditons, e.g. sediment
- 16 -