This effect creates vertical streams of bubbles based on the original image which you have imported.
As usual, the best way to see the possibilities of a single effect is to hit F8 or the 
icon in the toolbar..
With F9 (or the slider icon 
in the toolbar) you can change the settings of the bubble effect. The settings are:
| • | The total number of bubbles in the image |
| • | The average bubble size as a % of the x dimension of the image |
| • | The foreground color of bubble outlines |
| • | The background of the image |
| • | The highlight color on the bubbles, and from where the light is coming from which forms the highlight |