Longyearbyen (Svalbard), November 9, 2025 – After roughly two and a half weeks of research in the far north, the Norwegian icebreaker Kronprins Haakon returned to the port of Longyearbyen three days ago, emerging from the Arctic ice. The crew and the international team of scientists on board brought back valuable data and samples from the depths of the Arctic Ocean.
The expedition took the researchers as far as the 85th parallel north, about 500 kilometers from the geographic North Pole. Under harsh conditions and the advancing polar night, the scientists studied various oceanographic processes. One of the main goals was to better understand how ongoing climate change is affecting the fragile polar region.
The Kronprins Haakon is one of the most advanced polar research vessels in the world and a source of pride for Norway in the polar regions. It is equipped with state-of-the-art research technology – including underwater vehicles, multiple laboratories, and a helicopter deck. On this expedition, a CTD rosette, echo sounders, plankton and fishing nets were primarily used, explained Silje van Mierlo, a master’s student from Bergen.
At 23, Silje van Mierlo is among the young generation of scientists who are passionately shaping the future of marine research. As a student at the Institute of Marine Research (Havforskningsinstituttet) in Bergen, she had the opportunity to take part in this extraordinary winter expedition into the pack ice.
A Path into Oceanographic Research
Silje completed her bachelor’s degree in Marine Science at Eckerd College in St. Petersburg, Florida, and is now focusing on the carbonate system during her master’s studies.
The carbonate system describes the chemical balance between dissolved carbon dioxide, bicarbonate, and carbonate ions that regulates seawater pH, buffers acidity, and controls the ocean’s ability to absorb CO₂ and thus the survival of many marine organisms. Using a CTD rosette, she collected samples to measure depth, water conductivity, and temperature. These data provide essential information about how physical conditions change with depth. Additional analyses and water samples supply chemical data such as pH, dissolved CO₂, total alkalinity, and dissolved inorganic carbon. Only the combination of these measurements makes it possible to understand the state of the carbonate system.
In this way, scientists can identify main factors causing changes in the carbonate system and how ocean acidification is developing. Through regular CTD profiles, a detailed picture of chemical and physical changes in the ocean emerges – an important foundation for assessing the impacts of climate change on marine ecosystems.
Because these expeditions are repeated regularly, they also allow researchers to track changes over time and better understand the underlying processes.
Research in 24-Hour Operation
During the expedition, Silje often worked night shifts. Since other projects were also underway, work had to continue whenever the ship reached the respective research site. The scientific operations ran around the clock, yet daily life still followed a set rhythm:
07:30–08:00 Breakfast,
11:30–12:30 Lunch,
15:00 Afternoon coffee with cake and boller (sweet buns),
17:00–18:00 Dinner.
The scientific evaluation of the expedition is still in its early stages, but it is already considered an important contribution to understanding the Arctic winter months. “It’s too early to talk about specific results,” Silje says, “but we’ve already concluded that there are significantly fewer fish further north.”
However, this could change with the retreat of sea ice and shifting currents. “As the ocean warms, Atlantic water and fish species are moving farther north – a development with far-reaching ecological as well as geopolitical consequences,” Silje explains.
Life and Everyday Routine on Board
Despite the demanding work, the sense of community remained strong. “There was a good balance between scientific discipline and social togetherness,” Silje says. During breaks, people played cards or board games, held Mario Kart tournaments on the Nintendo Switch, or watched movies in the common room.
For a change of pace, there was a small gym, and the hangar area offered space for workouts or table tennis – a welcome way to unwind after long shifts. Because of the high latitude, the crew spent the entire voyage in darkness, with days and nights blending seamlessly into one another.
Encounters in the Ice
A particular highlight of the expedition was observing wildlife: “We saw seals and belugas, but despite many tracks we didn’t spot any polar bears – visibility wasn’t very good anyway.”
The most impressive moment of the voyage, however, came when the Kronprins Haakon broke into the dense sea ice. “The cracking and rumbling as the ship forced its way through the ice was unforgettable,” she recalls. Her cabin was right at the level of the ice: “You could constantly hear the crunching and grinding of the ice – a very special sound. I’ll miss it,” she says with a smile.
Marcel Schütz, Polar Journal