Steaming to the Southern Ocean: Part 4
This blog is intended to capture the experience of the Macrozooplankton and Micronekton team led by Evgeny Pakhomov, comprising Lora Pakhomov, Florian Lüskow, and myself on board the Alfred Wegener Institute’s Polarstern research vessel. From October 1st – November 17th for the PS 133-1 Island Impact cruise to the South Atlantic sector of the Southern Ocean, we will record daily insights of the activities on board, with a personal perspective of what it’s like conducting science at sea. All thoughts are ours and are not to be taken for media use. This work is funded by Alexis Bahl's 2022 Explorer Grant with the National Geographic Society.
Day 35: First ice
November 4, 2022
After leaving the Falkland Islands, the winds are with us and the RV Polarstern proceeds quickly on its way east-southeast. Noticeably, the days are becoming colder and rarely does the fog lift, preventing minimal visibility. Trained to endure grey ocean waters and appreciating already fine differences in lighting, we are excited about words spreading from the bridge – there are icebergs in sight! It is only early in the morning; some people enjoy their breakfast and Florian just woke up. Electrified by the thought to witness the drifting ice of considerable size (smaller pieces were observed already the day before), Florian and all awake scientists make their way up to the bridge or to higher decks to catch a view and the opportunity for a photo.
The following view is remarkable, maybe not because of the iceberg per se, but due to the crowd of scientists. Cameras, phones, and everything with a lens are now directed toward the two icebergs that pass the ship on the backboard side. They are accompanied by smaller pieces that most likely broke apart earlier on their journey. Dark elongated shapes are sighted calling for a more detailed observation with binoculars. Florian hopes for one or two penguins standing on the frozen drift islands, but his hopes will not materialize. The about one-meter-long structures are dark cracks in the ice. Regardless of the unfulfilled wish to see penguins, Florian and all the other scientists return to the mess room to warm up. This breakfast was chattier than most previous ones and our sightings spark the hope for more Southern Ocean highlights.
Photo credit: Lora Pakhomova.
Day 36: Ocean work in the shadow of the mountains
November 5, 2022
The first time after leaving our “weathering camp” at the Falkland Islands, we see land – South Georgia.
This isolated island south of the Antarctic Polar Front offers us again the opportunity to find shelter in the middle of a massive storm. In the lee of South Georgia, we spent about two days and take the opportunity to sample on the 250 m deep island shelf. The scenery is impressive as we work in the shadow of the South Georgia mountain range with peaks up to almost 3000 m – indeed, the highest mountains in all UK overseas territories. The view is breathtaking and makes us realize how monumental this sight must have been also for early polar explorers like Ernest Shackleton.
As on previous process stations, we deploy the RMT-8 and IKMT, but because the depth of the water column is relatively low, the tows are quick and already 20 minutes later, we receive the zooplankton samples on deck. Following the established sampling routine, Evgeny and Florian recover the nets and Lora rushes out to receive the cod-end containing the precious sample. On the light table, the sample is then analyzed by all team members. It is impressive that after only a few weeks, we can process the sample in a third of the time it took for the very first sample.
Mountain ridge on South Georgia (upper picture) and analysis of RMT-8 zooplankton catch on the light table (lower picture). Photo credit: Larissa Pattison (upper picture) and Annika Oetjens (lower picture).
Day 37: Disassembling the RMT-8
November 6, 2022
All good things must come to an end and after successful sampling on the South Georgia shelf, Evgeny, Lora, and Florian decided to disassemble the RMT-8. The 8.5 m2 net is a heavy instrument and it was therefore expected that it would take some time to take it apart, as well as clean and store it. After unscrewing the first metal connections, it suddenly begins to snow and should not stop until nightfall. Protected from the wind on the back of the ship, it took about 40 min to separate all parts of the net, bars, and weights – only half the time it took to assemble it at the beginning of the expedition. Having been used many times for sampling at this point, the RMT-8 smells like used fishing gear, so Evgeny suggests washing it with hot fresh water. Loaded on a Euro-pallet, the net was moved from the front of the working deck to begin the cleaning. It’s clearly a two- or three-person job, as the net itself is heavy and needs to be spread for the washing. Hot steam is flushing into Florian’s face while Evgeny hoses the net. By this point, the snowfall has intensified, and Florian feels reminded of the ship’s sauna (a luxury for all on board). Twenty minutes later, the net is clean and hung for drying with the help of a crew member. After two days of drying, the RMT net will be brought inside to get rid of any last bit of moisture. Next step: disassembling the IKMT net.
After the last night tow of the RMT-8 (left), Evgeny A. Pakhomov and Florian Lüskow take it apart, wash, and pack it (right). Photo credit: Annika Oetjens (left) and Lora Pakhomova (right).
Day 38: From penguins and whales
November 7, 2022
The days are now cold (air temperature is around freezing point) but the sea is calm, granting us great conditions for wildlife observations. In the previous weeks, we were unlucky in terms of whale or seal sightings, but the hopes are high as we steam toward the South Sandwich Islands. Scientists and technicians from the hadal team make sure their gear for sampling the deep-sea sediments in the South Sandwich Trench is ready. Hadal referring to the hadal zone, or the hadopelagic zone, makes up the deepest oceanic regions where deep-sea trenches host extreme marine ecosystems.
The first deployment site is exciting, as it’s also the deepest point in the Southern Ocean - known as Meteor Deep (> 8000 m). Using an instrument known as MUC, the hadal team begins sampling, while most other scientists, including Evgeny and Lora, find themselves more often than before on the upper deck looking for wildlife. Then, a few minutes before the MUC is expected back from its deployment on deck, somebody yells “Penguins!”- Florian’s favorite. Within minutes, Florian runs to the back of the ship onto the upper decks where a crowd of scientists peer into the water with the hopes of witnessing the bypassing seabirds. Four penguins are sighted jumping through the water like little dolphins and eventually rest near the ship and observe what strange “metal creature” is coming out of the ocean. Only minutes later, the penguins disappear, but then, humpbacks are sighted! The South Sandwich Trench stations prove themselves as most promising in terms of wildlife observations and new deep discoveries.
Teaming wildlife in the South Sandwich Islands region: humpback whale (upper picture) and penguins (lower picture). Photo credit: Evgeny A. Pakhomov.
To be continued....