Toroidal bubbles are when some ocean animals create a circulating rings that we can often see. These vortex rings are commonly made by dolphins and humpback whales, but they can be made in a variety of ways.
A toroidal, or doughnut-shaped, vortex is formed when fluid flows back on itself, making a spinning ring around an invisible core. The best-known examples of this phenomenon are smoke rings, produced by volcanoes and artillery, but perhaps the most intriguing are the bubble rings generated by marine creatures like whales and dolphins.
Toroidal Bubbles
https://www.youtube.com/watch?v=mHyTOcfF99o
