In amongst the weed and hanging from the surface film in the rockpool you'll almost certainly find large numbers of juvenile gastropod molluscs, each only a couple of millimetres long - this one is almost certainly a Littorina (winkle) species. Notice the single dark eye at the base of each antenna.
Acarine mites are incredibly diverse animals that live in almost every habitat imaginable (click here for more information on them). Scores of these little 8-legged animals, each only about a millimetre long, were scurrying around amongst the seaweed fronds. Not much is known about the ecology of marine mites, which mostly belong to a single family - the Halacaridae. Notice the long, hooked claws that stop them from being washed out of their seaweed shelter, and the piercing mouthparts at the head end. There's a short video clip below.