Today we pieced together the multi sensor track core logger in the sediment lab. The core logger provides down core data on physical properties such as magnetic susceptibility, P-wave velocity and gamma ray attenuation. These properties can be used to correlate certain layers between nearby sediment cores and also tell something about the depositional environment where the sediment was laid down.

During the day at least three polar bears were spotted!

We are now making our way through the pack ice towards the center of the Arctic Ocean. The helicopter is sent out to scout for open leads in the ice which we follow in order to avoid pressure ridges that can be several meters thick. Today we also got the official expedition T-shirt!

Since we left Svalbard, our Multibeam echo sounder has been logging continuously, with three watch-keeping teams day round. During the first two or three days, close to Svalbard and on the Yermak Plateau, some traces of erosion from iceberg and possibly ice shelves were quite exciting. But since we entered the abyssal plain of the Nansen Basin yesterday around lunch time, we have seen just see a vast and completely flat sea floor under 4017–4029m of water. In the last 24 hours we made it just about 140km northwards – cycling would have been at least twice as fast.

Oden continues to make slow but steady progress through the ice. When we find open lead systems in the ice, Oden can easily make 8–10 knots. In contrast, when Oden has to break its way through the more than 2m thick ice, the speed is often reduced to 1 knot.

Right now we are travelling over the central valley of the Gakkel Spreading ridge, meaning that we are passing from the Eurasian plate over to the Laurentian plate.

Markus Karasti during winch testing.

Today we had the opportunity to test the coring winch. Using the gravity corer’s head as a weight we lowered the weight down to 4000 m water depth and then pulled it back in to make sure that the wire was spooled back on the drum in a proper way. Despite some minor problems the test was successful and we are now eagerly awaiting the first coring station!

Now we have left the Lomonosov Ridge and entered the Makarov Basin in the Canadian half of the Arctic Ocean. Ice conditions made coring very difficult because ice floes kept drifting towards the wire when we were launching and retrieving the corer. Despite these problems we got a wonderful record of 2.7 m of sediment from more than 3800 meters of water depth!

After our excursion in the Makarov Basin we are now back on the Lomonosov Ridge. The Lomonosov Ridge is like a huge underwater mountain range stretching across the whole Arctic Ocean, from the shelf north of Greenland to the Siberian shelf. Usually, this ridge rises steeply from the abyssal plain at around 4000 m up to around 1000 m water. In the middle of the ridge, only about a degree from the North Pole, there is a large depression, like a basin within the ridge. The sediments in this basin are relatively undisturbed and should give us much information about the climate history of the Arctic Ocean. The coring team worked for 15 hours and in the end obtained two nice records about 6 m long before falling asleep exhausted at three o’clock in the morning.

Matti Karlström and some of the sediment cores we have taken so far.

Today we finished the coring phase of the expedition by taking two long sediment cores on the Eurasian side of the Lomonosov Ridge. On the two last stations curious seals have come close to the ship to find out what we are doing. Markus Karasti managed to catch one of them with his camera. The last few days have been hectic, filled with hard work around the clock. As a result, the coring team is totally exhausted, but now we will have a day of rest while heading for the North Pole.

Arm wrestling on the North Pole.

This evening we reached the North Pole! After a cheer on the bridge we all went out on the ice for a session of picture taking, flag waving and various other crazy activities. Mike Lampalugh (Canada) and Uni Bull (Denmark) engaged in arm wrestling, and after that Ludvig Löwemark and Benjamin Hell from Stockholm University got a hair cut by Uni, while Jeff Bowman (USA) was rolling around in the snow. Åsa Wallin and Matti Karlström (SU) took their mascots for a walk around the Pole. Frisbees were thrown, shirts ironed and some of us went off chasing the 90°N with a GPS. All while guards armed with shotguns and rifles were on the alert looking out for polar bears. After having the obligatory group photo taken, we went back to the ship's mess for some well deserved hot chocolate, wine, beer and a late night snack.

Benjamin Hell doing snow angels on the North Pole.

Watchint out for Polar bears.

Getting a new haircut.

We have now turned around and slowly started to move back towards Svalbard. The days are filled with laboratory work and data acquisition. All the cores obtained during the hectic days last week must be opened and described, and all the equipment must be cleaned and repaired, and lists be made over things that should be replaced before the next cruise. There is not much life on the ice here and everybody is looking forward to the ice margin, the transition zone where the pack ice gradually disintegrates into the open ocean, because that’s where we will have the biggest chance of seeing polar bears and seals again.

Åsa Wallin is inspecting one of the cores retrieved last week.

This evening we had the traditional surströmming dinner. Surströmming is a very special form of herring that divides people into devoted followers and those who cannot stand it. The herrings are produced in a way that allows the fermentation process to continue inside the cans. When the cans are about to explode from the pressure build-up inside the can, the herrings are ready to be eaten. Opinions during the dinner varied from “delicious” to “never again” …

Crew onboard Oden claysculpturing.

The scientific program is now more or less finished and we are cruising South through the pack ice on our way back to Longyearbyen. People are working on their contributions to the cruise report that will sum up our achievements. In the evening we arranged an art contest using clay that we collected when describing and sampling our sediment cores. Over twenty sculptures were created during the evening, and the work with the clay obviously released some of the wild imagination stored among the scientist and crew onboard Oden.

The chief.

Mike Lamplugh came running up to the bridge with a wild expression on his face shouting “polar bear, polar bear!”. A mother and her two cubs were walking along Oden for more than an hour giving us ample photo opportunities before slowly disappearing into the distance.

Polar bear with cubs.

Longyearbyen. Photo: Martin Jakobsson

Now we are back where we started, anchored outside Longyearbyen. The expedition has finished and tomorrow we will fly home. It has been a fantastic expedition, both scientifically and personally. A big thanks to the crew on Oden and everyone who helped make this expedition such a success!