Dead seaweed has uses. The Pelvetia of the marsh, dry or sodden, seems to help on the growth of other plants; through its decomposing masses the fleshy leaves of sea purslane (Obione) and aster push to the salt-laden air. Where it lies, tide-drifted, with other heterogeneous litter, the small crustaceans of the shore find that it gives shelter; beneath the weed are sand-hoppers and small crabs enjoying damp shade until the next tide brings the longed-for water.

Yet it is not always a safe refuge, for there are still some turnstones that have not left our shores for northern homes, and they find dead weed easier to throw over than heavy beach pebbles. We watched these beautiful little “tortoiseshell plovers” systematically working the tide-line. When one reached a likely looking patch of weed the head was lowered so that the short, slightly uptilted bill could be pushed well under; one quick upward stroke and over went the shelter, and the bird pounced on as many of the light-surprised refugees as it could catch before they hopped away or burrowed in the sand. When all the best weed had been turned the little flock, with trilling notes and flickering wings, hurried off to find a fresh spot for investigation.

Source: theguardian.com