Underwater observatory deployed
In mid-September 2025, a long-term underwater observatory was successfully deployed near Ultima Thule, a hydrothermal vent site in the Lena Trough between Svalbard and Greenland first discovered by CDeepSea researchers in 2023.
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The deployment, carried out by the Swedish icebreaker Oden, with support from GoNorth 2025 (external link), is part of the national research infrastructure NOR-EMSO. The observatory consists of a lander and multiple sensors calibrated and prepared by CDeepSea, which will gather critical data and serve as an important test for future deployments. Placed northeast of the vent field, it is one of the deepest of the northerly moorings and is in a location that is both scientifically valuable and difficult to reach. (The next GoNorth cruise, led by Steffen Leth Jørgensen, aims to revisit the site in November if sea conditions allow.)
The Ultima Thule vent field includes a black smoker chimney estimated to be up to 10 metres tall. Black smoker vents emit hot water, sometimes reaching 400°C, that appears black due to chemical interactions with underground rocks. The chimney is located on Lucky Ridge, a 1600-metre-high subsea mountain range rising from a valley floor at 4000 metres below sea level. The unique geology of this particular ridge makes it an extraordinary natural laboratory for studying the interplay between seawater, mantle rocks and life.
The instruments in the observatory include conductivity, temperature and depth (CTD) sensors, nine temperature sensors and a high-accuracy pressure sensor. Together, they will provide continuous measurements of water properties close to a hydrothermal system. The data will help improve our understanding of how heat, minerals and chemical compounds spread through the deep ocean environment. This information is of interest to anyone studying hydrothermal systems, which host unique ecosystems based on chemical energy rather than sunlight.
Scheduled for recovery in 2026, the observatory's data will be available to the scientific community, advancing our understanding of the Arctic deep sea.