World's Deepest Gas Hydrate Cold Seep Discovered Off Greenland, Teeming with Life

Groundbreaking Discovery in the Greenland Sea

An international team of scientists, led by researchers from UiT The Arctic University of Norway, has announced the discovery of the world's deepest known gas hydrate cold seep. Located off the coast of Greenland on the Molloy Ridge in the Greenland Sea, this remarkable deep-sea ecosystem, dubbed the Freya Hydrate Mounds, was found at an unprecedented depth of 3,640 meters (approximately 11,940 feet). The findings, which reveal a vibrant community of life thriving without sunlight, were recently published in the journal Nature Communications.

Understanding Gas Hydrate Cold Seeps

Cold seeps are areas on the ocean floor where fluids rich in hydrocarbons, such as methane and hydrogen sulfide, seep out from the Earth's crust. Unlike hydrothermal vents, which release super-heated fluids, cold seeps typically emit fluids at temperatures similar to or slightly warmer than the surrounding seawater. These seeps create unique environments where specialized organisms, known as extremophiles, can flourish through a process called chemosynthesis, converting chemicals into energy rather than relying on sunlight.

The Expedition and Its Revelations

The discovery was made during the Ocean Census Arctic Deep–EXTREME24 expedition in May 2025. Researchers were initially alerted to unusual activity by the presence of massive methane gas 'flares' rising more than 3,300 meters through the water column, among the tallest ever recorded globally. Following these plumes, a remotely operated vehicle (ROV) was deployed, leading to the visualization of the Freya Hydrate Mounds. This site extends the known depth range for gas hydrate outcrops by nearly 1,800 meters beyond typical occurrences, which are usually found at less than 2,000 meters.

A Thriving Ecosystem in the Abyss

The Freya Hydrate Mounds are home to a diverse array of marine life, including:

• Siboglinid and maldanid tubeworms
• Skeneid and rissoid snails
• Melitid amphipods
• Various microbes

These organisms have evolved unique adaptations to survive the high pressures and near-freezing temperatures of this extreme environment, utilizing methane and sulfide compounds for sustenance. Professor Giuliana Panieri, co-chief scientist of the expedition, noted that the discovery 'rewrites the playbook for Arctic deep-sea ecosystems and carbon cycling,' highlighting the system's geological dynamism and biological richness.

Implications for Science and Conservation

The discovery offers new insights into how life can persist in extreme conditions, with potential implications for astrobiology and the search for life on other celestial bodies with subsurface oceans. Furthermore, the unexpected ecological overlap between the life forms at the Freya mounds and those found at Arctic hydrothermal vents suggests a previously unrecognized connectivity between diverse deep-sea habitats. This connectivity underscores the importance of protecting these 'island-like habitats' from potential future impacts, such as deep-sea mining, which is currently under evaluation in the region. Scientists emphasize that understanding these unique environments is crucial for safeguarding biodiversity and informing responsible decision-making in polar regions.