BECKYHITCHIN
As above , so below
Our science writer Becky Hitchin continues her tour of Great Britain ’ s coastal geology . Part 2 : Farne Islands to Chesil Beach
You may remember that back in the January issue , we took a journey around the shores of Scotland to look at how the underlying geology affects our diving . This time I ’ d like to carry on round the English coasts , which start just a smidge south of our favourite weatherbeaten sites of St Abbs and Eyemouth .
First we come to the Farne Islands , known and loved for encounters with voracious carnivores who like chomping on fins and various other bits of diving equipment . Seals are an essential part of Farne Islands diving , and the presence of these grey seals does again depend on geology . We have two species of seals common to UK shores – grey seals and common ( harbour ) seals . While common seal pups are born with the ability to swim , grey seal pups are not . So grey seals prefer living around rocky shores , where they can pup slightly inland . If the Farnes were all sandy , it ’ s likely that we ’ d be swimming with common seals instead .
Moving further south , we come into more challenging areas of diving . From north Norfolk round to the English Channel , just getting in the water can be demanding . But rewarding . North Norfolk shores are home to a Marine Conservation Zone protected for incredible , delicate chalk reefs , likely to be the longest chalk reef in Europe , possibly the world . The life growing on and living among the chalk arches and reefs is different from that in any of our other coasts , with at least one sponge known only from these reefs . So why is the diving different from that further north ? Well , we ’ re now jumping into the Southern North Sea , which is a very different environment from the old volcanic rocks and clear upwelling waters of the west coast . The Southern North Sea is a shallow , contained basin , no more than 40m deep in most places , with huge sediment loads coming in both from large rivers such as the Thames and from eroding cliffs . This generally leads to a heavy sediment load in the water , and often frustrated divers and photographers .
Moving south , these sandy , muddy , sediment shores continue round to north
“ I actually did my first ever open water dive at Chesil ”
Kent , where again chalk outcrops around the Thanet headlands . One interesting dive there isn ’ t a geological issue , but a manmade one . If you ’ re ever near Walpole Tidal Pool , go and have a swim , snorkel or dive . It ’ s amazing what you can find in that pool on the beach : sponges , lobsters ... even lumpsuckers .
We head round to the English Channel , the domain of deeper wrecks and strong tidal currents . A buddy and I once dived on the Dornier DO17 discovered off southern Kent . I didn ’ t actually see it . Or my buddy . Or the seafloor . I spent 15 minutes hanging onto the line , feeling like a flag flying from a flagpole in high winds in zero visibility before crawling back up the line and flopping into the RIB . But really , the diving round there is stunning , on good days .
Leaving Kent , we head through Sussex ( the SS Pentrych is a great dive out of Brighton by the way ), Hampshire and on to Dorset where the intimating expanse of Chesil Beach awaits divers . I actually did my first ever open water dive at Chesil , and wondered what on earth I was letting myself in for . Here the interesting geology is also above water . This huge barrier beach created of pebbles of just the right size to annoy the tired diver was formed at the end of the last Ice Age , as Dogger Bank was being lost . It was formed from sediments initially from Lyme Bay , and has been a fully-formed feature in that area for at least 4000-5000 years . Exactly the time it feels for me to drag myself up over the beach after a dive .
Next month , we ’ ll head through Cornwall and Devon to Wales ’ s islands and tidal straits , up to the north west coast of England and back to where we started . �
Scenes from the Farne Islands , above the water line
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