Each time we visit this beach, the landscape of the strand has changed. Giant boulders are exposed or disappear completely. Bladderwrack accumulates in spongy piles – tricky to walk on – then is taken back by the sea to leave smooth clean sand. Sometimes there’s sea coal, at other times heaps of periwinkles and limpets. Wind and tides are forever shaping and reshaping the coast.
Today, after a turbulent sea, there are crunchy razor clams underfoot. Sharp-edged, they were named after the cut-throat razors used for wet shaves. These are molluscs that drag themselves beneath the sand using strong muscular “feet”. To make their downward passage smoother they shoot out a jet of water, which led to the delightful Scottish name of spoots. Their pale shells stand out against the background of sea‑moulded nuggets of coal, along with broken crab claws and the spiral skeletons of whelks.
Festooned over it all are heaps of straw-coloured strands, floppy like long catkins or cereal bran sticks. I scoop up a handful and marvel at the intricate beauty laid out in my palm. These are the tubes of the sand mason worm, Lanice conchilega, normally buried like the razor clams but washed ashore by rough seas instead. Each multicoloured tube is a necklace of tiny fragments of shell and rock, cemented together to protect the body of the worm, in a similar technique to that of caddis fly larvae in rivers. The worm has a fringed top of tentacles, a miniature palm tree, for catching any passing food of plankton, algae or decaying plants; it’s normally the only thing visible when it sticks out of the seabed.
What I hold in my hand is a microcosm of the landscape, each grain telling a story of its origins. Sparkling quartz, Cheviot granite, honey-coloured feldspar, black whinstone, stacked in methodical order to create the mason worms’ home. If the sediment increases in depth, the worm can simply build more, though it’s not enough to protect against wading birds with specialised sensitive beaks. Curlew and redshank probe the shore and can tweezer out the worm, pulling it from its now redundant tube in a protein-rich meal for a hungry wader.
• Under the Changing Skies: The Best of the Guardian’s Country Diary, 2018-2024 is published by Guardian Faber; order at guardianbookshop.com and get a 15% discount
