When an air bubble rises in water what happens to its potential energy?

no matter what happens to the bubble, even if it sinks or rises, the mass will remain the same throughout. we all know that as we go deeper into water, the pressure increases with the depth. hence, when the bubble rises, the pressure exerted on it decreases and simultaneously, the volume increases. that is all that happens to the bubble. the mass remains constant unless it bursts. the mass of air in the bubble originally is now dissolved in the water. always remember that the mass of anything is constant as long as it is acted upon the same gravitational force.