There are two Drej Stingers in this scene. One is flying above the water and the other is actually submersed below the surface. The bubbles were created with Softimage Flock animation. If you look closely, you can still see the reflections of the stinger flying above the water.

The motion of the gas trees is generated by secondary animation of the water's movement. Also, the reflections of the trees in the water was generated simply by turning on ray tracing.