Hill End to Spaniard Rocks & Back: Step-by-Step Part 6

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As my walk continued from Hill End northwards on Rhossili beach, the dark drift patterns and fine strandline debris covering the sand eventually faded away to be replaced by dry sand ripple and swash/backwash patterns before arriving at the extreme north-east corner of Rhossili beach. This is the place where much of the flotsam ends up. It is not that Gower visitors are careless with their trash. Most of this stuff comes from far afield – sometimes as far away as South America. It does get periodically cleared away but is difficult to manage because the rubbish arrives and leaves with each tide, and can get buried or revealed from one high water to the next. Bicycle wheels, brightly coloured plastic pieces, fishing net and ropes, toothbrushes, balloon stoppers, and flip flops are common items along with the driftwood. The pile of organic and plastic rubbish lies adjacent to Spaniard Rocks which connect the tidal island of Burry Holms to Llangennith Burrows.

The geology here is interesting but on this occasion I focussed on the seaweeds which attach to the rocks along the water-filled channel between Burry Holm and Spaniard Rocks. There are many types intermingled. They include amongst others the brown Fucoid algae such as Toothed Wrack (Fucus serratus) , Spiral or Flat Wrack (Fucus spiralis), and Egg or Knotted Wrack (Ascophyllum nodosum). Bladder Wrack or Pop Weed (Fucus vesiculosus) was also present but not in its typical form. The numerous small, paired, almost spherical air bladders typical of the species were few and far between on specimens in the area where I was looking – so that there is confusion in my mind as to the identity of some of the weed I have named as Spiral Wrack.

There were also some red algae of the thin bladed type that dry out between tides into blackened streaks on the rocks (of the kind to which the lavabread seaweed belongs). Another red alga was the Sand Binder seaweed (Rhodothamniella floridula) which forms small humps of fine filaments trapping sand grains on rocks low on the shore; it is often found beneath the taller stalked fucoids. Finely branching red Polysiphonia lanosa was epiphytically attached to the Egg Wrack.

Of special interest this visit was the fact that the seaweeds were getting ready to reproduce. The Spiral Wrack had swollen receptacles on the forked frond tips that were not fully ripened yet. However, the Egg Wrack was ready to go. It has separate males and females. The male receptacles are bright golden green studded with orange pustules (conceptacles) that release a colourful fluid containing the sperms. I had seen these and reported on them before. This time I also saw the female receptacles which were dull green and covered with minute darker almost black blisters (conceptacles) containing the eggs. It almost seems as if you can see the eggs when you zoom in on the picture – actually just the light bouncing off the ripe eggs within the pustule.

18 Replies to “Hill End to Spaniard Rocks & Back: Step-by-Step Part 6”

  1. I love the seaweed pictures – just lovely! It never ceases to amaze me what the tide washes up – I love beach combing to see what unusual and lovely things the tide has depsited! The sand patterns are lovely too – they would make the basis for some lovely abstract art… !


  2. Thank you, Evelyn. It was altogether a great walk that I am currently documenting post by post – not least because of all the patterns on the beach. I have always seen these as examples of natural abstract art and have often played with the images using digital colour transformations to further extract the abstract. Recently, I have been experimenting with digital painting, having been inspired by i-pad paintings in the latest David Hockney exhibition at Tate Britain.

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  3. You may be right. I am not certain which of the seaweed images you are looking at but in 115 and 116 I have called the species Fucus spiralis with unripened receptacles on the basis that I could not find at the time or on the photograph any of those distinct paired spherical air bladders so characteristic of Pop or Bladder Wrack (F. vesiculosus) on the stems. There did appear to be the beginnings of the “flange” that is typical of Spiraled Wrack around some of the receptacles. I have looked at all the other photographs I took on the day and have now found some specimens with a few rounded air bladders much lower on the stalk, maybe as much as 30 cm away from the receptacles. There is also one distinct air bladder on a stem in image 121 (showing the Sander Binder seaweed) that is of the typical type for Pop Wrack. I have now discovered from the Seasearch Guide to Seaweeds of Britain and Ireland by Bunker et al that “in some circumstances the classic air bladders do not form. One notable instance is on exposed shores where air bladder development can be indistinct or absent. Aberrant forms can also occur in sheltered conditions and confusion can occur, particularly with less spiraled individuals of Spiraled Wrack”. I wonder even if there are hybrids between the two species? Anyway it looks as if I have misidentified the specimens. Thank you for pointing it out if you were referring to those particular pictures. I’ll check it all with an expert.
    In the images 117, 122, 123, and 124 illustrating Egg Wrack, all the air bladders are typical of that species, although they are variable in size they are always very large compared with F. vesiculosus, have an ovoid shape, and occur singly along the stem.


  4. Hello Jessica
    As you might recall from an earlier comments I made, Rhossili is one of my all-time favourite places in the world – and once again you have captured your recent walk magically for those of us who pine for our far-away beloved places.

    Just this weekend I returned from a long weekend break wandering the west coast of Vancouver Island around Ucluelet – Tofino, taking photos in much the same spirit as yours – natural patterns, seaweeds, flotsam from the winter Pacific storms etc. I didn’t see any massive die-off events and the pebble beaches are less entertaining being mostly from the lavas and granites in that area. Lots of extensive “log beaches” of cast up dead trees and roots from the extensive forests that reach right down to the shore line all along BC’s west coast.

    What prompts me to write to you however are photos 106 and 107 on this page and 126 on the next post.which are almost identical to some I took on Long Beach – so much so that I briefly thought they were taken on the same stretch of beach on the same day! Of course not! The beaches are over 7400 km apart!

    Just thought you’d like to know that these patterns do repeat elsewhere! I guess there’s nothing new under the sun, wherever It’s shining.


  5. Hello Paddy
    Thank you for writing. I am so glad you enjoyed walking along Rhossili beach with me. I had hoped that readers would like to share my experience of that great seashore. As you have discovered, the patterns in the sand are not unique to Rhossili. I have been trying to work out how each of the pattern types are created and during that research have found out that they have a global occurrence dependant on common conditions being in place.
    It sounds like you had a great trek too along the west coast of Vancouver Island. I wish I could see what you have seen. Have you thought about writing a blog? Or maybe you are still too busy in your retirement – I wonder if you have transferred any of those old 35mm colour slides to digital format yet?


  6. Thanks for the all the wrack info, Jessica. I see it is all far more complicated than I had thought. TBH we rather unscientifically follow our granddaughter in calling any seaweed that has a bladder that bursts with a satisfying ‘pop’ and a squirt of liquid in the eye “pop wrack”. I think this usually turns out to be what I know as bladder wrack.


  7. Hello Jessica
    Thanks for replying! I’m working hard at the scanning business – very tedious really – but with wonderful memories brought alive again. I got side-tracked into making some photo-books to share with family. Once I have sorted the photos I’ll decide the best way to share them and your blog is a great template – I’m sure you’ve been told that by many people! Sometime this year I promise. Keep up the great work that you do!


  8. Hello again Jessica
    Below is a link so you can view the Long Beach patterns I photographed – you don’t need a password or to have Dropbox installed.

    Interestingly, the beach profile of Long Beach and Rhossili Beach are very similar – a long flat gentle slope seawards and a similar fine sand texture. The “peaks” in the patterns point towards the sea and as the incoming water gently washes in over the sand and back out again it only changes the patterns a minuscule amount with each wave, presumably sorting and sifting the heavier and lighter material into the patterns we see. Not sure what affect heavier surf would have. I’ll leave the link open for 7 days.



  9. I see. Not all seaweeds have air bladders. Usually it is the small paired air bladders of bladder wrack that are popped, giving it its alternate name of pop wrack, especially if they are a bit dry – rather like popping bubble-wrap bubbles but better. You can’t do that to the big egg-shaped air bladders of egg or knotted wrack because they are too tough. If you squeeze the squidgy things at the ends of the fronds to squirt liquid, those are the seasonally swollen reproductive parts of the seaweed.

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  10. Well done with all the scanning, Paddy. It is great to re-live all the experiences from old photographs. I like to compose photobooks too but on topics like my Impressions of Rhossili, Rocks around Louisbourg, Natural Geological Abstract Images – it’s a shame that they are not really a viable proposition for selling because of the expense of this kind of self publishing – but most of the images are on Jessica’s Nature Blog anyway. It’s just that it is good to see the pictures in a hard copy format sometimes.
    I look forward to seeing some of your pictures when you eventually set up a blog.


  11. Thank you very much. Paddy, for letting me have a look at your photographs of sand patterns from Long Beach. I have had a look at them on Drop Box and they are amazingly similar to the ones I have taken on Rhossili Beach. There have been occasions when I have been able, as you have, to watch the patterns forming in clear shallow lapping water. I have tried to capture the movements on video but not with great success. However, it is fascinating to observe sand pattern and sand ripple formation which are the subjects of scientific studies of their own.


  12. What’s the betting that someone somewhere has already done that? Sounds like great undergraduate/graduate thesis stuff! Keep up the great work.


  13. You are right. A great deal of research has been already achieved in this subject area – part of which is referred to as beach and shoreface morphodynamics. Many scientific disciplines are involved in the investigation of ripple formations and beach sediment patterns.


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