The expedition Arctic Ocean 2025, blog post 6: Polar bears, multi-beam sonar and examination
During this week it has become clear that we moved into the autumn freeze up. There is almost no open water around us at all anymore. Where open water was present previously, between the more solid ice floes, the ocean is now covered with a layer of new ice.
Finally, after over four weeks in the Arctic, we got to see a couple of polar bears; a mother and a 2nd year cub. Photo: Michael Tjernström.
But the new ice takes different shapes; sometimes it is so plastic that waves move through without breaking the surface, sometimes there are large thin sheets and when these collide a large zipper-like pattern forms, but sometimes it is just gray and solid like frozen slush. The polar bears we passed by the other day benefit from the new ice since they don't have to swim from floe to floe. They are excellent swimmers but the water is cold!
The polar bears we passed by the other day benefit from the new ice since they don't have to swim from floe to floe.
The weather has also improved some and we feel the freeze up also in the air temperature, that has dropped to -10 degrees Celsius and below, especially when the clouds dissipate and the sun comes out. When it is foggy – which is quite common – it is a little less cold, but then we are also accumulating a lot of frost – on the ship and on the instruments. We have continued to conduct a few science stations sampling water, sea ice and sediments, continuous measurements on board and to fly out teams on the ice with the helicopter. But a main task has been to map the sea floor with the multi-beam sonar for a project called Polar Connect, investigating where it is possible to lay down a fiber-optic cable across the Arctic.
A "fogbow", a cousin to the rainbow. Unlike in raindrops, these cloud droplets are so small they only reflect white light. In a rainbow, the drops are so large that the solar radiation is refracted like in a prisma and reflected inside the rain drop. As with the rainbow, a fogbow is only visible when looking away from the sun. Photo: Michael Tjernström.
Nurse Johan, student Luisa and chief scientist David performs in the starboard mess during the Talent Show, onboard icebreaker Oden. Photo: Michael Tjernström.
The organized part of the research school has wrapped up with the last lectures a week ago. The last workshop group presentations was last Wednesday. The students read, discussed and presented their conclusions on the Central Arctic Ocean Large Marine Ecosystem synthesis and did a great job of a difficult task. It does feels like we are all collectively learning something each time we get together to discuss. The students are working on their individual reports, that is part of their examination.
It does feels like we are all collectively learning something each time we get together to discuss.
Among the happenings was the Talent Show on last Thursday; completely voluntary off course with several performances of music and poetry. Serious and fun mixed up for a great time together with friends – everyone won first prize!
Farewell dinner in the main mess hall, with everyone gathered. Photo: Michael Tjernström.
Saturday we had the great "Farewell Dinner", a tradition on these expeditions. Although we will be together one more week before leaving Oden next Friday, we wanted to hold the dinner before getting out in the open sea where Oden has a tendency to roll a bit. Since we always dress up a little and have a nice dinner together on Saturdays, to mark the passing of another week, this was a nice fit and an extra nice dinner on white sheets with speeches and handing out of the expedition certificates.
(Michael Tjernström, 14 September 2025)
Sun came ut with a double halo (rings around the sun) and two sun-dogs on the horizon. These are due to refraction of solar radiation in ice particles and requires that one look into the sun. Photo: Michael Tjernström.
The icebreaker Oden has set sail and is heading for the Arctic to map the seabed. On board are 21 PhD students from various countries attending a research school where practical work is combined with lectures. Follow their journey in our blog, with weekly reports by Michael Tjernström, professor emeritus of meteorology at Stockholm University with extensive experience of Arctic expeditions, and responsible for the research school.
