Methane-rich plumes on the Carolina continental rise: Associations with gas hydrates

Seafloor venting of microbial gases occurs at 2167 m water depth over the Blake Ridge diapir-Gas-rich plumes were identified acoustically in the water column up to 320 m above a pockmarked sea floor associated with active chemosynthetic biological communities. Plumes and venting fluids emanate from near a small fault that extends downward toward a dome in the bottom-simulating reflector, indicating that fluid and/or gas migration is associated with gas hydrate bearing sediment below. These plumes might be caused by gas bubbles or buoyant dumps of gas hydrate that float upward from the seafloor. 18 refs., 3 figs.