Sheep skull on a signpost along the Welsh Coastal Path, at Whiteford Sands, Gower, South Wales.
The shape of natural abstract sand sculptures, like these ripples on the seashore, result from complex interactions of water and substrate which are the subject of much research in the field of fluid mechanics. They are described as “small-scale three-dimensional bedforms due to interactions of an erodible bed with a sea wave that obliquely approaches the coast, being partially reflected at the beach” (Roos & Blondeaux 2001). Different combinations of three main perturbation agencies create different ripple designs.
Roos, P.C. and Blondeaux, P. (2001) Sand ripples under sea waves. Part 4. Tile ripple formation, J. Fluid Mech. vol. 447, pp. 227-246.
Yesterday I posted pictures of a massive tree trunk that is being washed out of the peat on the beach at Whiteford Sands. It is lying on its side. Next to it are the remains of a clump of smaller trees. [I have indicated their positions with arrows in a context shot below]. The trees were growing close together. Only the stumps survive but they are preserved upright in their life position, complete with root systems penetrating downwards through the peat. I noticed for the first time in preparing these photographs for the post that someone has very neatly and professionally cut off one of the tree roots; this may substantiate my assumption that someone is in fact carrying out research on the newly emerging trees of this submerged forest.
Some of the ancient wood that has long been buried in peat and clay deposited after the last ice age has wonderful textures and woodgrain patterns. Whole recumbent tree trunks have been emerging from the peat as a result of recent beach erosion at Whiteford on the Gower Peninsula in South Wales. This wood is not fossilised but is preserved in its original state by the anaerobic conditions in which it was buried – in the same way that the bodies of the so-called Bog People were preserved.
You don’t exactly have to keep your nose to the ground to see them but you do have to be a keen observer to notice all the different tracks and trails left on the soft wet sediments of the beach at low tide. Larger marks left by people and vehicles are the first ones you see. Bird footprints are every where. The birds are feeding on all sorts of invertebrate seashore creatures like worms, small crustacea and molluscs – all of which leave holes, burrows and furrows as they move in and out of the sand and across the surface. Some of the pictures shown here simply aim to give the general context for the area of Whiteford Sands that I was walking across. If you look closely the other images, you will see not only the ripples in the sand but also the intricate network of traces left by the virtually invisible organisms that inhabit this ecosystem. The larger furrows in photos 1, 12 and 13 are made by the common winkle (Littorina littorea Linnaeus). I cannot name each animal that is responsible for each of the other types of trace. However, I am sure that there will be some specialists out there who could, especially those researchers concerned with the interpretation of trace fossils (the ichnologists).
Click images to view full size.
At low tide many thousands of common winkles or periwinkles (Littorina littorea Linnaeus) seek shelter from dessication and predation by clustering together in the few hiding places available on the beach. At Whiteford Sands these niches include the overhung bases of larger stones, crevices in ancient timbers from the rapidly emerging submerged forest, and nooks and crannies in the recently exposed ancient peat. Alternating layers of peat and clay, overlain by rocks from glacial till, provide algae-covered surfaces on which gastropods can feed, and islands of low tide refuge in the vast expanses of sand on this sea shore.
Crisp and cold, bright and sunny, just right for blowing away the cobwebs with a walk along the strand at Whiteford Sands. On this particular winter’s day the tide had brought ashore lots of flotsam – fishing nets, buoys, floats, and crates, shoes, hard hats, and miscellaneous plastic rubbish that rested on a driftline of sand, pebbles or shells. Here are some of the things that caught my eye as I strolled the high water mark from Cwm Ivy Tor to the spit beyond Whiteford Point on Boxing Day 2013. Click on any of the images in the gallery below to view in a larger format and slideshow.