The rock ledges below the new sea wall at Church Cliffs in Lyme Regis, Dorset, are the upper strata of the Blue Lias limestone. The natural limestone ledges and the smooth artificial substrate of the concrete sea wall, provide a home for numerous seashore creatures like limpets, winkles, and top shells as well as many commonly attached red, green and brown seaweeds, and encrusting calcareous algae (pink Lithamnion). The brown substance sticking to a lot of limpet shells is also an encrusting seaweed (probably Brown Limpet Paint Ralfsia verrucosa).
Multitudes of small holes penetrating the rocks are the often-occupied burrows of small marine polychaete worms like the Polydora species. Occasional drifts of sandy ripples coating the stone are punctured by largish round holes where bivalved burrowing piddocks living in the rocks below have squirted jets of water from their exhalent siphons and cleared the sand away.
It is interesting to see that the seashore life is equally at home on the old concrete footings from the defunct breakwaters as it is on the limestone.
The shore beneath the new sea wall in Lyme Regis looks very different now the old breakwaters or groynes have been removed. You can still see the linear concrete footings of the old wood and iron structures but most of the pebbles and cobbles that used to accumulate between the walls are now absent (at least for the moment). A bare rock pavement is revealed, comprising a series of steps representing the strata and colonised by seaweeds. Rippled sand sometimes deposits in the valleys between the rock ledges.
This was almost the last time that I saw the old sea wall and breakwaters at Church Cliff in Lyme Regis. As part of a scheme to improve the sea defences in Lyme Regis, the breakwaters were demolished a few years later and the old sea wall, as it was seen in these images, disappeared from sight and was replaced by a stronger structure more fit for purpose and providing additional amenity value. I was surprised how different these shots were from the earlier ones from 2010. The tide was in and covering seaweed and cobbles, the light was different and had a big impact on the colours observed, and it was a different camera and that had an effect too.
The main sea defence structure at Church Cliff in Lyme Regis back in 2010 and 2011 was a concrete sea wall. This was built into the base of a cliff that is made of soft slipping strata. It was from the sea wall that the iron and wood breakwaters jutted out at right angles to deflect the impact of the sea. The concrete wall in part held back the cliff and in part prevented undercutting by the waves. Over time the wall had become stained by run-off from above and by lichen and bacterial deposits to form interesting striped patterns with subtle variations like an almost monochromatic natural abstract art along the length of the wall. This wall has since been replaced by a much stronger structure, along with the demolition of the breakwaters.
Follow in my footsteps with a virtual walk along beautiful Rocquaine Bay on the west coast of the Channel Island of Guernsey. It is protected by a long sea defence wall which has employed different construction techniques along its length; mostly using local stone but also with along stretch of reinforced concrete (probably originating from German occupation World War II fortifications). The beach is both rocky and sandy with some pebble patches. Seaweeds of every colour abound. Huge limpets with white shells cluster on the bright orange-spattered L’Eree granite bedrock while outcrops of monochrome microgranodiorite occur on the upper shore near Fort Grey. Marine worm casts cover the softer muddy sands. Streams flow across the shore, their clear shallow water reflecting sunlight from the ripple crests and creating shadow patterns. A small stone jetty looks marooned among the rocks and a multi-coloured carpet of weed. Small boats bobbing in the turquoise water, rusty buoys and chains half-buried in seaweed, and algae-encrusted mooring ropes add to the evidence for fishing and leisure boating activities.
Click on the first picture to view the images in the gallery in the sequence that they were taken during the walk.
The pebble bank on the seashore at Annestown is retained by a low sea wall that curves from one end of the bay to the other. (You can see it on the right of the picture above). It stops incursions by the sea in rough weather, and also prevents the movement of the pebbles inland. The car park is mostly tucked behind the sea wall but where an opening allows access to the beach, recent winter storms and wave-borne beach stones have pounded and ripped-up the tarmac.
A footpath follows the landward side of the wall from east to west. The wall is high enough to fulfill its function and low enough to allow walkers to enjoy the view at all times. The construction of this sea defence is interesting, seemingly made up from individual blocks of small pebbles in a cement matrix, and the blocks then cemented together to form the wall. It looks as though the wall is using local materials in an attempt to blend better with the surroundings. However, the rough surface is colonised extensively by black, yellow, and white lichens whose distribution varies, presumably according to the degree of exposure to prevailing sun and wind and rain, making the wall stand out as a feature rather than merge with the landscape – although there is a certain resonance with the dark cliffs and headlands beyond.