Exploring the Deep Sea: The EXTREME 25 Expedition and the Contribution of ROVs to the Multidisciplinary Characterization of Arctic Extreme Environments

On November 11, 2025, the RV Kronprins Haakon set sail from Longyearbyen dock, launching the EXTREME 25 expedition. This significant research expedition ended on November 26 when the research vessel returned to Tromsø harbour, bringing back new knowledge and findings. Led by the Department of Geosciences at UiT - The Arctic University of Norway, this expedition was a collaborative effort involving numerous esteemed institutions from around the world.

Figure 1. Researchers and students during ROV operations on the EXTREME25 expedition. Credits: Valentina Lanci (UiT)

This expedition marks the second phase of UiT's EXTREME mission, which began on 2024 (https://oceancensus.org/expeditions/arctic-deep/) and builds on the experience gained from previous centre of excellence CAGE (https://site.uit.no/cage/), the AKMA project ( https://en.uit.no/project/akma) and the discoveries made in 2023 of the Borealis Mud Volcano (https://uit.no/nyheter/artikkel?p_document_id=811650).

The primary aim of the EXTREME 25 expedition was to explore the dynamic deep-sea ecosystems, such as cold seeps and hydrothermal vents, in Norwegian waters from the Fram Strait to the Barents Sea.

These environments are characterised by the emission of hydrocarbons or hydrothermal fluids from the seafloor. Investigating these depths, often hundreds or thousands of metres below the surface, presents considerable challenges. To overcome these challenges, the international team onboard, led by Prof. Giuliana Panieri (UiT-CNR), collaborated with the NORMAR team to operate the Ægir 6000 ROV. This state-of-the-art remotely operated vehicle (ROV) was equipped with a comprehensive suite of samplers, enabling the collection of geological and biological samples and high-resolution seafloor imagery for orthomosaics and habitat mapping.

The ROV's capabilities have created new opportunities for deep-sea exploration, such as locating white patches of microbial mats that signal fluid emissions, thereby improving our understanding of these special environments and their influence on ocean dynamics.

The samples and data collected with the Ægir 6000 ROV will be analysed in the coming months. This will help us better understand this unique ecosystem and its global significance.

Figure 2. Close-up view of bacterial communities thriving at the vent site. The distance between the two green laser points is 9 cm, providing a scale for the dense microbial structures visible on the seafloor. Credits: UiT; NORMAR/ROV Ægir6000.

Figure 3. The ROV team during the diving operation in the vessel's moonpool area. Credits: Valentina Lanci (UiT)

Figure 4. The ROV team operating from the remote container situated on the surface vessel. Credits: Valentina Lanci (UiT)

“There is still so much we don’t know about the deep sea, and the EXTREME expeditions should be regarded as successful examples of multidisciplinary collaboration in addressing global challenges,” stated Dr Claudio Argentino, Co-cruise leader and researcher at UiT. “During the expedition, I spent considerable time in the ROV container, which gave me more opportunities to make decisions during the dives. It was an exciting experience, but I also realised how stressful it can be to stay focused for hours while making the right decisions. The ROV team was exceptional, providing logistical suggestions whenever needed, both before and during the dives.” 

Figure 5. Dr Claudio Argentino supervising the ROV team during the ROV dives. Credits: Valentina Lanci (UiT).

But Extreme 25 was not solely focused on science. In fact, with over 30 participants from diverse fields—including geology, biology, micropaleontology, natural sciences, art history, sound and visual arts, illustration, and anthropology—the expedition also aimed to integrate scientific research with artistic expression.  In this context, the ROV played a key role in one of the most unusual artistic performances during the early days of the cruise. Gry Bagøien, a skilled Danish sound artist whose work connects humans with the Ocean's song, used a speaker in the ROV moonpool to project her voice into the ocean, attempting to harmonise with the underwater robot's sounds during its dives. Using a hydrophone to record her vocal performance, she aimed to create a new language that resonates with the ocean's diverse elements, including the ROV, marine life, and the cold waters around them. Her presence onboard culminated in a spontaneous singing performance around the moonpool, with all expedition members and many crew members gathered to sing for the sea and their underwater robot. This act not only aimed to raise awareness of our dependence on the seas but also encouraged reflection on the use of advanced technology to explore deep-sea environments inhospitable to humans.

Figure 6.  Gry Bagoien, crew members, and expedition participants during the singing performance around the ROV moonpool. Credits: John Grzinich; NORMAR/Ægir6000

Figure 7. Professor Giuliana Panieri (UiT; CNR-ISP). Credits: Martin Hartley.

Giuliana Panieri, professor of geology at the UiT - Arctic University of Norway in Tromsø and director of the Italian Institute of Polar Science, who led the project and expedition, explains, "Combining multiple disciplines enhances our ability to observe and understand the sea. This isn't just about different scientific fields but also about disciplines with diverse cultures, backgrounds, and methods. Gaining new perspectives on familiar topics can inspire us to think differently. Although multidisciplinary collaboration can be challenging, requiring openness to unfamiliar approaches, it's precisely this challenge that keeps us curious and motivated to continue".

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About the EXTREME25 expedition

The EXTREME 25 expedition adopts a multidisciplinary approach, bringing together scientists, students, media experts, and artists from around the world to explore extreme environments. This research cruise stands out not only for its scientific results but also for the breadth of expertise on board. Alongside geologists, geophysicists, geochemists, methane specialists, and marine ecologists, the expedition hosted: an active delegation from the National Research Council of Italy (CNR), representing multiple institutes and disciplines; a team of chemists and engineers from Woods Hole Oceanographic Institution; researchers from EXTREMES, a UArctic-supported initiative exploring the intersection of aesthetics, art, and science; scientists from the University of Bergen contributing expertise in deep-sea chemosynthesis-based ecosystems; scientists from University Milano Bicocca supporting the high-resolution mapping effort; microbiologists from University of Naples Federico II; micropalaeontologists from University of Vienna; anthropologists and artists studying human–polar interactions and new modes of science communication; a project supported by Equinor and NOD, focused on understanding subsurface processes and methane pathways.

Explore the StoryMap Expedition to learn more about the EXTREME 25 Expedition: https://storymaps.arcgis.com/stories/b646a515db214abcb8320035f0cd12ee  

To stay updated about EXTREMES, visit the project website: https://uit.no/project/extremes  and the project Instagram page: @extremes_arctic