Measurements of the fate of gas hydrates during transit through the ocean water column

We report on controlled experiments to document the fate of naturally occurring methane hydrate released from the sea floor (780 m, 4.3degreesC) by remotely operated vehicle (ROV) disturbance. Images of buoyant sediment-coated solids rising (similar to0.24 m/s) from the debris cloud, soon revealed clear crystals of methane hydrate as surficial material sloughed off. Decomposition and visible degassing began close to the predicted phase boundary, yet pieces initially of similar to0.10 m size easily survived transit to the surface ocean. Smaller pieces dissolved or dissociated before reaching the surface ocean, yet effectively transferred gas to depths where atmospheric ventilation times are short relative to methane oxidation rates.