ANT-XXVI/1, Weekly Report No. 1

16 October 2009 - 25 October 2009

The POLARSTERN leaves on schedule the harbour of Bremerhaven on October 16th, 2009 at 9 pm accompanied by frenetic applause and Mexican waves from the crew of the school ship ALEXANDER VON HUMBOLDT, the staff from the shipping company Laeisz and the Alfred Wegener Institute (AWI) as well as from the family members of the cruise participants. The ship is on the way to Antarctica via Las Palmas (Spain) and Punta Arenas (Chile), where the first leg of the 26th Antarctic cruise (ANT-XXVI) will be completed on 25.11.09.

A red dot was following us. It is the light of the camera of the German NDR TV team, which films the new LIDAR-System. This system is able to measure concentration and distribution profiles of atmospheric aerosols up to 30 km height. LIDAR means Light Detection and Ranging. The system has been built by the Institute for Tropospheric Research (IfT) in Leipzig and is integral part of the OCEANET project.

In the dead of night at 4 pm we pass the British Channel, Europe’s largest “ship highway”. According to our Capitan the passage was quite and decent. Unfortunately we are not able to see the famous white Cliffs of Dover.

The first day on board is dominated by the preparation of the upcoming scientific investigations and experiments, which will characterize the rhythm on deck and in the labs during our journey. During the first meeting a detailed plan for each single ship station and the respective working programme are jointly elaborated.
 
At the next daily meeting we are steeled by our meteorologist from the “Deutscher Wetterdienst DWD” for the upcoming low. This is bad news as besides rain and strong winds ranging from 7 to 9 on the Beaufort scale, we also have to face a swell of up to 6 m for the next days. Obviously, the malicious Bay of Biscay keeps its promises.

On October 20th at 1 pm the first CTD measurement starts. The CTD probe measures Conductivity, Temperature and Depth. Additional sensors and water samplers can be added to the CTD system to collect seawater samples on different depth and to provide additional information about other physical or chemical seawater parameters. The ship provides the user permanently with seawater, which is used for continuous measurements of chemical, biological and oceanographic parameters. A new autonomous CO2 sensor, which will measure initially the CO2 concentrations in deep water, is installed for the first time on POLARSTERN. Those data are important to better understand CO2 exchange and the interactions between water and atmosphere.

On the second half of the day the mobile friction winch planned for use during the next expedition of the research vessel “SONNE” is tested. A 3000 m cable is deployed into the nearly 5000 m deep water with a small weight and then recovered and stored back perfectly on the winch again.

The strong waves dominate the organisation of the scientific work. The combination of the northwest swell and the west to southwest wind brings us waves of 8 to 10 m height und dictates the rhythm of the scientific work on board.

On 23rd October in the afternoon a final test with 5-tons weight was carried out on the friction winch and took the whole afternoon. However, the highlight of the day is the trial of an underwater camera system, which is mounted on a small sediment grab together with two under water lamps. The whole unit is lowered to about 2500 m depth. The camera is connected via an 8 km long cable to the control computer. Mesmerized by the pictures obtained, the scientific team is starring at the screen and watching the slow gliding of the green claw into the dark. After camera recovering, the whole Laeisz, AWI and iSiTEC team, who developed and designed the camera system, were satisfied by this success. This new camera system was used for the first time to transfer real on-line images at high quality using the normal coax cable. This tool makes the use of marine equipments visible and effective.

In the night from 23rd to 24th October, the POSIDONIA system is calibrated. POSIDONIA is an acoustic positioning and communication system, which is able to detect, locate, communicate and recover moored equipment at great depth at the seafloor. The intensive calibration work was carried out during all the night. The calibration has been successfully completed and the system is now ready to be used at any time.

For Saturday 24th of October a barbecue is planned. But before the party starts a number of trials have been still to be undertaken. The mobile winch, the CTD and the underwater camera are tested again. At about 9 pm the POLARSTERN starts to depart to the next location, where the calibration of the multibeam sonar “HYDROSWEEP” has to be carried out. Like the PARASOUND system, HYDROSWEEP is a sonar system and mounted on the hull of the POLARSTERN. This multibeam sonar produces high-resolution bathymetric charts of the seafloor.

Since Thursday, we left the storm region and heading slowly to the island of Gran Canaria, which we will arrive on 27th of October in the morning.
 
The PARASOUND school is completed. During our 10 days trip, the students have learnt how to operate the sediment echo sounder which emits and receives acoustic waves and allows us to profile the sediments between 0 and 130 m under the sea floor.

The weather is getting better and better. For Sunday our weatherman continues to predict good weather ahead and we take advantage of the last sun before we disembark on next Tuesday.

 All cruise participants, who will disembark in Las Palmas would like to say good bye to colleagues and crew members and would like to thanks them for the effective and fruitful cruise.

Many greetings from all cruise participants of the POLARSTERN,

Bonnie Wolff-Boenisch / Saad El Naggar