About Weddell seals and ROV
By Dominik Nachtsheim
It has been a long way, but we made it: On 20th December Polarstern successfully approached the shelf ice edge despite heavy ice conditions in the Atka Bay. The unloading of cargo and fuel for Neumayer-Station III and the Kohnen Station started immediately. The whole process was coordinated and performed perfectly by the team from Polarstern and Neumayer Station III. A farewell event took place in the evening of 21st December. Hereafter, we left Neumayer III behind, as well as the South African research vessel SA Agulhas II, which has been waiting to unload in the bay, and steamed in southwesterly direction.
Next to some containers also new people entered the vessel: the seal and ROV team, consisting of Horst, Nils, Richard and Dominik. Our arrival was quite different compared to that of our colleagues onboard Polarstern. From Bremen and Frankfurt, respectively, we travelled via Munich to Cape Town on the 7th December. After a two day stay in the city at the famous table mountain we proceeded to Novo Airbase in Antarctica onboard an Ilyushin Il-76, a Russian cargo aircraft. Since the weather conditions were perfect, we could directly head to Neumayer-Station III but not before having a hot soup in the local canteen. At Neumayer-Station III we spent 10 days preparing our upcoming project and exploring the Atka Bay as an alternative study area. Our actual final destination and prioritized study area is the Drescher Inlet, a 25 kilometer long crack in the Riiser Larsen Ice Shelf. We are going to establish a camp, and operate it for five weeks, from which we are able to work independently.
In the Drescher Inlet we are going to equip Weddell seals with small cameras, which take photos in intervals of a few seconds over several days. For this the seals will be immobilized by our experienced vet Horst and the device will be glued to the fur on the head of the seal. By this means we aim to investigate the intake of food items by the seals. We are especially interested in dives, which target the underside of the shelf ice. From previous campaigns we know that a poorly known faunal community, described as ‘hanging gardens’, inhabits this area. These could be very worthwhile to visit for Weddell seals due to a potentially abundant food resource. Moreover, we are going to deploy a remotely operated vehicle (ROV) to further investigate, record and quantify the under shelf ice fauna. At the end of our campaign some seals will also be equipped with satellite-linked dive loggers not bigger than the palm of a hand, which track the animals’ movements over the next months. At the latest in one year seals will shed off all devices during their annual moult.
The few days we spent onboard were used to prepare the set-up of our camp at the Drescher Inlet. Our whole freight must be transported from the vessel to our camp location by helicopter. This requires accurate planning, especially because we should not forget anything important on-board Polarstern. A team of scientists and crew members will be dropped at the shelf ice at our camp location to take over our freight, while a second team on-board will eagerly re-load the helicopter upon return from the camp. We will probably need a full 8 hour working day until our camp is fully equipped. From then on we are there by ourselves and Polarstern is going to pick us up again from the Drescher Inlet in the end of January.
At Polarstern’s first station, at which several devices from almost each working group were deployed, first samples were obtained. Now we are steaming towards Drescher Inlet, where we may arrive at the 26th December. As always in the Antarctic, all plans and calculations are dependent on the weather and ice conditions. So, we will see what happens and will report about the arrival of the seal & ROV team at the next opportunity.
Happy Holidays and best regards from board of Polarstern,
Dominik Nachtsheim
