Beneath the Greenland Sea, Frozen Methane Towers Hide an Entire Ecosystem: How Do Creatures Survive Here?

Four kilometers below the icy surface of the Greenland Sea, the ocean appears to be otherworldly. It is pitch black, nearly freezing, and crushingly pressurized.

In December 2025, scientists investigating Molloy Ridge discovered an amazing sight: towering structures composed of methane ice rising from the ocean floor.

Methane hydrates are structures composed of methane and ice.


They are formed when methane is trapped in icy water under extremely cold temperatures and high pressure.

The study Deep-sea gas hydrate mounds and chemosynthetic fauna discovered at 3640 m on the Molloy Ridge, Greenland Sea describes this as the deepest methane cold seep found in the Arctic Ocean.

How Do These Ice Towers Form?

Deep under the seafloor, methane slowly collects over thousands of years. The strong pressure and cold water let it join with water and become ice-like. Sometimes, the gas moves upward. If the hydrates break down or the ground shifts, methane escapes as bubbles that can rise almost 300 meters through the water.

Tests show that the methane here comes from deep underground, made by heat and pressure, not from rotting plants or animals near the seafloor. As the gas moves and freezes again, it slowly builds the tall mounds that look like frozen reefs. The process is explained in the research Methane Hydrate Dynamics in Arctic Cold Seeps.

Life Thrives in the Darkness

What surprised scientists even more was the life found around these icy towers. Groups of tubeworms, like siboglinid and maldanid types, cling to the mud. Tiny snails from the skeneid and rissoid families move along the mounds, and small amphipods scurry across the seafloor.

Without sunlight, plants cannot make food. Instead, the ecosystem depends on chemosynthesis. Tiny organisms turn methane and other chemicals into energy, making the start of a food chain that supports bigger animals. These cold seeps create small areas full of life in a place that otherwise seems empty, according to the research Chemosynthetic Communities in Arctic Methane Seeps.

Are These Hidden Habitats Linked?

Researchers noticed that many species at Molloy Ridge look like those found near Arctic hot water vents, like the Jotul vent field on the Knipovich Ridge.

This suggests that methane seeps and hot vents might be linked, letting species slowly move across the deep Arctic seafloor. Learning about these links helps scientists understand how life survives in tough conditions and changes as the oceans change, according to the Biogeography of Arctic Deep-Sea Chemosynthetic Fauna.

Exploring the Inaccessible

Human divers cannot reach depths of 3,640 meters. Instead, the team used remote-controlled robots with cameras and tools. These robots took close-up videos of the mounds, the bubbles, and the animals living there.

The team also brought mud and water samples to the surface to study the chemistry and how this hidden ecosystem works. Thistechnological approach is detailed in ROV-Based Exploration of Deep Arctic Methane Hydrate Systems.

Why These Discoveries Are Important

Methane hydrate mounds are not just frozen oddities. They are important habitats that add to Arctic biodiversity and affect how methane moves through the environment, which matters for climate predictions. Discoveries at Molloy Ridge show that even the most remote and harsh parts of our oceans are full of life and complexity.

Every deep-sea expedition reveals a world that most people will never witness. The frozen reefs of the Greenland Sea prove that, even under dark and cold waters, nature finds amazing ways to survive.