[1] The physics of vortex rings are still under active study in fluid dynamics.

[4][5] As the bubble ring rises, a lift force pointing downward that is generated by the vorticity acts on the bubble in order to counteract the buoyancy force.

The ring becomes thinner, despite the total volume inside the bubble increasing as the external water pressure decreases.

Circulation increases the velocity while reducing the rate of radial expansion.

This rotation moves the fluid around the bubble creating a toroidal vortex.

[9] Air bubbles with a diameter greater than about two centimeters become toroidal in shape due to the pressure differences.

Dolphins sometimes engage in complex play behaviours, creating bubble rings on purpose, seemingly for amusement.

[12] There are two main methods of bubble ring production: rapid puffing of a burst of air into the water and allowing it to rise to the surface, forming a ring; or creating a toroidal vortex with their flukes and injecting a bubble into the helical vortex currents thus formed.

They also appear to enjoy biting the vortex-rings they have created, so that they burst into many separate normal bubbles and then rise quickly to the surface.

Dolphins also have the ability to form bubble rings with their flukes by using the reservoir of air at the surface.

[13] Humpback whales use another type of bubble ring when they forage for fish.

They surround a school of forage fish with a circular bubble net and herd them into a bait ball.

[14] Some scuba divers and freedivers can create bubble rings by blowing air out of their mouth in a particular manner.

Long bubble rings also can form spontaneously in turbulent water such as heavy surf.