The methane hydrate blowout aboard the RV Sonne research vessel turns a seabed sample into a lethal chain reaction. A video grab driven into a worm-covered hydrate deposit broke through without resistance; gas erupted from the opening, engulfed the equipment, and sent its metal jaws swinging across the ship’s stern. A Statoil technician was killed. The accident made the unstable ground itself an immediate threat and forced the researchers to change how they would investigate it.

Sampling the Worm-Covered Hydrate

The crisis began as the researchers examined a seabed scene crowded with mussels and writhing worms. The worms appeared to be feeding on the mussels: jaws shot from their bodies and tore away pieces that disappeared into the tube-like forms. Beneath the mass of animals lay white methane ice, though the monitor no longer showed it clearly. Bubbles rose through the sediment with small, shimmering fragments of hydrate. The apparent abundance of life thus concealed a volatile geological layer, and the researchers’ attempt to sample that layer brought the hidden condition into the open.

When Bohrmann gave the signal, the seabed rushed towards the camera. The image briefly suggested that the worms were rising towards the equipment; then the screen went black as the grab’s iron jaws entered the methane and closed. The panel’s numbers spun rapidly. The grab had broken through and was sinking, an alarming failure of the expected resistance from the seabed. Bohrmann ordered it pulled up. The operator reversed the joystick, and the grab began to rise with its jaws still clenched.

Its cameras revealed the scale of the disturbance: a vast hole had opened, swollen bubbles surged from within it, and a stream of gas struck and engulfed the grab. The picture disappeared in the resulting turbulence. The sampling device had not merely collected material; its penetration had opened a pathway through which the gas could escape.

The Blowout on Deck

The danger quickly moved from the seabed to the ship. As the RV Sonne reached full speed, the sea began bubbling and white lumps shot to the surface. The cable tightened with a clunk, while two Statoil technicians stood beneath the stern’s A-frame, looking down. The first officer ran towards them, warning them to get clear. The warning came amid several events at once: a foaming geyser engulfed the stern, and the video grab rose through the surface. The vessel’s stern sank under the force of the eruption; then the grab’s metal jaws swung sideways through the air towards the ship’s topside.

One technician threw himself down. The other froze, then stepped backwards and stumbled. The first officer sprang forward to pull him to safety, but the jaws struck the technician and threw him onto the deck. Johanson and Lund ran towards the motionless man, but the first officer told them not to touch him. Bohrmann later confirmed that the technician had been killed on impact. The sudden movement from a controlled sampling operation to a fatal deck emergency showed how the consequences of disturbing the seabed could reach the people working above it within moments.

What the Accident Revealed

Afterwards, Bohrmann described the incident as a blowout: the grab had penetrated more than twenty metres into the hydrate before gas came up. The hydrate layer had been estimated at a minimum thickness of seventy to eighty metres, but Bohrmann qualified that estimate after the breach. The grab’s descent, the enormous bubble seen on the screen, and the gas that engulfed the equipment made the deposit’s condition more than a theoretical concern. The failed sample had exposed an unstable opening in a thick layer.

The researchers also considered the wider consequences of methane release. Bohrmann discussed the possibility that a sufficiently large blowout could reduce the water’s density enough for a ship to sink, and noted that large blowouts occurred in the region between Bermuda, Florida, and Costa Rica. He presented this as an explanation to be investigated, not as a demonstrated cause of the accident aboard the RV Sonne. The event therefore widened the inquiry: the danger was not confined to a troublesome organism or a damaged instrument but could involve the behaviour of gas and water on a far larger scale.

Changed Methods, Unsettled Questions

Bohrmann decided that the next sample would be taken with an autoclave corer rather than another grab, because it was safer. A corer could preserve sediment, hydrate, pore water, and local organisms under maintained temperature and pressure, avoiding the abrupt disturbance associated with the failed attempt. The team later excavated twelve cores without another incident. They stored the sealed tubes upright in a walk-in freezer, but the material could not be analysed aboard ship; it required the GEOMAR deep-sea simulation chamber to recreate the appropriate conditions.

The accident also sharpened Bohrmann’s doubts about the purpose and control of the research. The project existed because Statoil had found a worm, and the immediate industrial concern was how to remove the perceived problem. Bohrmann warned that the worms might not be the true source of danger: solving the worm problem could make matters worse if the underlying cause lay elsewhere. The death aboard the ship gave that warning force. The blowout was not proof that the worms had caused the instability, but it demonstrated that investigating them through poorly suited intervention could produce its own severe consequences. The event left the central scientific question unresolved while changing the practical terms on which the researchers could pursue it.