Thus, the ubiquitous existence of bulk nanobubbles is a direct consequence of the compressed amphiphile monolayer model: unavoidable existence of trace organic contaminants that act as a source of amphiphiles, and the interface adsorption of amphiphiles and shrinking of large bubbles that lead to the formation of compressed amphiphile monolayer, and the bulk nanobubbles with such a monolayer are thermodynamically stable. The ubiquitous existence of bulk nanobubbles in aqueous solutions may have significant effects on a variety of processes that are related to bubble formation and disappearance.