Micro-rock-pooling

This is probably the low point of the year for exploring life in seaside rock pools but if you search amongst the fronds of seaweeds like the red Ceramium and green Cladophora, that can still be found on sheltered parts of the shore, and take them home for microscopic examination you can still find a wealth of marine life in miniature. Here, beautifully camouflaged in a flecked green exoskeleton, is a sea slater Idotea sp.

The multi-facetted compound eye of Idotea is exceptionally beautiful.

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.

You can find more on freshwater marine mites here.

Cyclops with Hitch-hikers

This little crustacean, about a millimetre long, is Cyclops, with a single red eye-spot in the centre of its head - a minute freshwater counterpart of the monocular monster of Greek mythology. My garden pond is swarming with them at present, even though the ice has barely thawed. If you take a close look at the top end of the tail, near the body, you can just make out clusters of short-stalked objects attached to the animal's exoskeleton. At higher magnification these turn out to be....

.......... Vorticellids - single celled protists with beating cilia around their mouth, creating a whirlpool current that sucks in foot particles. You can see a movie of Vorticella in action here. At even higher magnification..........

..you can see their cilia and the contractile vacuoles that they use to expel waste (double-click for a larger image). Vorticellids attach themselves to all sorts of small pond animals, hitching a ride.

As Jonathan Swift (1677-1745)  noted,

So, naturalists observe, a flea

Has smaller fleas that on him prey;

And these have smaller still to bite ’em;

And so proceed ad infinitum.