The acoustic signature of marine seep bubbles

Abstract

Observations of seabed bubbles (62m depth) at a natural marine hydrocarbon seep by passive acoustic and optical approaches are compared. The acoustic and optical methods observed a bimodal distribution with peaks at 1500 and 1750Hz, and 2200 and 2800μm radius, respectively. Radii were ~20% lower than predicted by the Minnaert formula. Frequency shifts were observed for bubbles emitted within a few milliseconds and were attributed to coupling between nearby bubbles. Surfactants also may have played a role.