The fourth and final GoNorth expedition will take place from 27 November to 17 December, uncovering secrets hidden on and beneath the seafloor north and west of Svalbard. After three years of systematic exploration in the Arctic Ocean, this year’s voyage is both a conclusion and a last deep dive into some of the most inaccessible geological structures and marine ecosystems in the region.
One of the main objectives is to measure temperatures and collect samples at Ultima Thule, the hydrothermal vent field located during the 2023 GoNorth expedition. It is a rare find in the Arctic Ocean; a site where hot, mineral-rich fluids rise from the deep seafloor, creating pockets of extreme life. Whether the team will reach it this year depends entirely on weather and ice conditions; at the moment it looks challenging, but not impossible.
As an alternative target, the Molloy Deep is expected to be far more accessible. The Molloy Deep is the deepest point in the entire Arctic Ocean, so deep that it features rocks that are fragments of the Earth’s mantle; material that is normally hidden beneath the crust. Since it lies on a bend in the Arctic mid-ocean ridge, the site gives geologists access to rocks formed when the seafloor was pulled apart and fractured. The area also hosts steep slopes, complex faults, and submarine landslides, making it a natural laboratory for understanding how the deep seafloor forms and reshapes itself.
Farther north lies the Sophia Basin, another high-priority target if conditions allow. This basin has never been mapped in detail, and two seamounts within it remain largely unexplored. If the ice lets the team in, they hope to send sound waves down through the seafloor to create a cross-section of the basin — a method known as seismic profiling. These profiles could reveal how the Arctic and Atlantic oceans have been connected or separated through deep time. Instead of a simple story where the Arctic Ocean went from “closed” to “open,” the geology may show several cycles of opening and closing.
Seismic profiling on this expedition is once again made possible through the participation of our long-standing friends and collaborators at GEUS Denmark (the Geological Survey of Denmark and Greenland), who also took part in the GoNorth cruises of 2022 and 2024. Their expertise and equipment are essential for imaging the structures hidden beneath the seafloor.
A record number of biologists on board
This year’s expedition also brings a record number of biologists to the Arctic Ocean for a GoNorth expedition, with a total of five. Several teams are focusing on a different layer of life on the deep seafloor. Together, their work will help reveal how organisms survive, interact, and shape their ecosystems in one of Earth’s most extreme environments.
Petra Hribovšek (UiB) hopes to investigate chemosynthesis at hydrothermal vents — the process in which organisms create their own energy from chemicals in the water rather than sunlight. This type of metabolism is common both at hydrothermal vents (underwater hot springs) and at their colder relatives, cold seeps, where energy-rich fluids leak out of the seabed. Petra focuses on microbes: how they interact with each other and with their environment. Using a special ROV-operated syringe, she hopes to collect samples of the biological “goo” growing directly on hydrothermal chimneys, allowing her to study the microbes in situ. She will also take sediment samples in and around vent areas to understand how these microbial communities use methane as an energy source.
Arunima Sen (UNIS) is turning her attention to the larger animals that inhabit vents and seeps. With the ROV, she plans to create a detailed image mosaic of selected patches of seafloor, essentially stitching together multiple images. This will let her identify species, map where they occur, and see how they relate to one another and to the terrain. Her PhD student, Carla Lopez Mateo, will be studying meiofauna: tiny animals that live between grains of sediment. To find them, she will collect push cores; with the ROV pushing a tube in the sediment layer to bring back a sample. These will help reveal how different microhabitats near vents and seeps shape the tiny communities living there, and how the chemistry of those environments affects what survives.
Arunima and Carla will also collect animal samples for carbon and nitrogen isotope analysis. Carbon isotopes will indicate where each species gets its food: whether the carbon originates from deep-Earth fluids rising through the vents or from surface-derived material drifting down from above. Nitrogen isotopes, meanwhile, will help determine each organism’s position in the food chain.
Thomas Dahlgren will be collecting sediment samples both with the multicorer and with the ROV, aiming to analyse environmental DNA (eDNA). This is genetic material that organisms leave behind in their surroundings. In deep-sea sediments, this includes everything from microbial traces to fragments shed by much larger animals. By examining this DNA, scientists can detect species without ever seeing them directly. Thomas plans to sample several deep-sea regions: the Norwegian Basin northwest of Lofoten, Mohn’s Ridge between Norway and Greenland, and the Greenland abyssal plain farther north, with an objective of comparing the fauna across these distinct environments. This approach can reveal the presence of organisms from the microscopic to the macroscopic, offering a uniquely comprehensive view of biodiversity.
Understanding how different these areas are, and how unique their ecosystems may be, is valuable information for policymakers, especially as discussions about the future of deep-sea mining continue to intensify. In addition to sediment samples, Thomas will also collect water samples for eDNA analysis, enabling scientists to compare genetic traces in the water column with those in the sediments and with the species observed in the ROV imagery.
Tracking moisture in the Arctic atmosphere
Throughout the expedition, the ship will continuously measure water vapour isotopes in the air. These isotopes act as natural tracers, revealing how moisture moves through the atmosphere and how temperature and humidity shape that journey. Because isotopes respond subtly to processes like evaporation and condensation, they provide a powerful way to check whether climate models capture the rapid changes that occur when wind blows across sea ice and open water. Project lead Hans Christian Steen-Larsen (UiB) is monitoring results from land as they come in, and promised to share some of them before the end of the expedition, so stay tuned.
Better ice maps through big data Big data and machine learning are becoming central tools across many fields, and sea-ice science is one of them. The idea is simple: imagine icebreakers equipped with arrays of sensors that continuously collect data, which is then automatically processed to improve models of sea-ice conditions. Such models could help ships plan shorter, safer, and more fuel-efficient routes, reducing both costs and emissions. To move toward this vision, researchers need to prototype sensor systems, gather data, and see what the results look like under real Arctic conditions. This year, PhD candidate Ashiqul Alam Khan (NTNU) returns for a second round of testing, after taking part in last year’s expedition to northern Greenland. His upgraded setup will combine lidar and thermal cameras with standard optical cameras, allowing him to map sea ice in greater detail and under a wider range of conditions.
Better ice maps through big data
Big data and machine learning are becoming central tools across many fields, and sea-ice science is one of them. The idea is simple: imagine icebreakers equipped with arrays of sensors that continuously collect data, which is then automatically processed to improve models of sea-ice conditions. Such models could help ships plan shorter, safer, and more fuel-efficient routes, reducing both costs and emissions.
To move toward this goal, researchers need to prototype sensor systems, gather data, and see what the results look like under real Arctic conditions. This year, PhD candidate Ashiqul Alam Khan (NTNU) returns for a second round of testing, after taking part in last year’s expedition to northern Greenland. His upgraded setup will combine lidar and thermal cameras with standard optical cameras, allowing him to map sea ice in greater detail and under a wider range of conditions
About GoNorth
GoNorth’s objective is to push the boundaries of knowledge about Norway’s neighbourhood in the Arctic Ocean, from the sea floor and subsea geology, to the sea ice, via the water column. The project was launched in the wake of the 2009 decision by the UN’s Commission on the Limits of the Continental Shelf to grant Norways territorial claims on its northernmost shelf. GoNorth is led by NORCE.
GoNorth’s fourth expedition runs 27 November to 17 December.
