Arctic Ocean, 17 September 2026

A few days ago, we experienced a true scientific highlight. A conversation between a young researcher and a senior professor earlier in the expedition set an intense planning process in motion. The target was one of the hydrothermal vents along the Gakkel Ridge.

Where new ocean floor is formed

The Gakkel Ridge is an underwater mountain range extending approximately 1,800 kilometres from Siberia to the north-eastern coast of Greenland. It rises several thousand metres above the surrounding seafloor. What makes this mountain range special is that it forms what is known as a spreading zone. It lies at the boundary between two tectonic plates – the Eurasian and North American plates – which are slowly moving apart at a rate of less than one centimetre per year.

At the centre of the ridge is a deep rift valley where new ocean floor is formed as magma rises from the Earth’s interior. Hydrothermal vents can be found within this valley. Water several hundred degrees Celsius in temperature and with a distinctive chemical composition flows from these vents. We had now set out to find one of these vents and investigate its outflow.

Hydrothermal vents transport heat and chemical substances from the Earth's interior. They can provide researchers with insights into both processes within the Earth's crust and microorganisms that thrive on chemical energy in an environment completely devoid of sunlight. We had set out to locate such a vent and examine its discharge.

Earlier discoveries showed the way

As is so often the case in science, we benefit from those who have gone before us. In 2001, a polar expedition used an American and a German research icebreaker. The vessels travelled along the Gakkel Ridge, and one of the expedition’s results was the discovery of several hydrothermal vents (Edmonds et al., 2003). Our route turned out to pass directly over one of them.

A signal at a depth of 3,300 metres

When the expedition management gave the go-ahead for a sampling station at the Gakkel Ridge, a flurry of activity began among several of our research teams. The idea was to position Oden beside a suitable ice floe and then drift with the ice across the site. The sea-ice experts calculated the direction and speed at which the ice floe and Oden were expected to move during the survey. The seafloor researchers started up their instruments to locate the hydrothermal vents.

Once in position, the oceanographers and plankton team lowered a CTD rosette, which measures parameters including temperature and collects water samples at selected depths. This time, we were looking for a plume of warmer water expected above the hydrothermal vent. We used the CTD like a yo-yo, raising and lowering it between 2,500 and 3,700 metres to detect a temperature anomaly.

Finally, we picked up a signal between 3,200 and 3,400 metres, where the water showed an elevated temperature. What a moment!

The plankton team will now analyse several water samples to investigate the chemistry and biology of the warmer water mass. The analyses will help determine whether the water originates from a hydrothermal vent. Overall, the sampling station at the Gakkel Ridge showed how researchers from different parts of the expedition worked hard together to achieve their goal: finding traces of a hydrothermal vent.

With this final blog post, I sign off and hope that you, the reader, have gained some insight into life on board Oden during the Canada–Sweden Arctic Ocean 2026 expedition.

Text: Henrik Swärd, Teacher Programme participant