New Particle System, Hairs, Debris, Dust

I am not too familiar with the new Blender particle system. I am making an underwater scene, and I need to have floating dust/particles. How can I make something that emits floating dust particles? (preferably strands too-- for added realism) Thank you in advance!

This is my scene: http://img510.imageshack.us/img510/2487/underscreeniemw7.jpg
Here is an example of what I’m looking for: http://thedirtonpregnancy.files.wordpress.com/2008/03/underwater-vector-4.jpg