Do water bubbles explode or implode?

If you shake up a glass of water, a bunch of bubbles form at the surface then slowly pop as the turbulence settles down.

So, is the pressure inside those temporary bubbles higher or lower than the surrounding air/water?

The pressure must be more or less equal to the water, as the bubbles aren’t rigid.

They burst, emptying their contents into the air, as the water displaces them.

Because of surface tension in the skin of the bubble, the pressure inside the bubble is slightly higher than local atmospheric pressure. You can observe this with a kid’s bubble wand: blow a bubble, but leave it attached to the wand and unsealed: surface tension will cause the bubble to shrink, blowing the air back out toward you through the hole in the wand.