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

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.

Flat Wrack at Fermoyle

It was tranquil at Fermoyle on the Dingle Peninsula. Hardly a soul on the long sandy part of the beach, and only a solitary angler on the red rocky promontory at the western end. Vast swathes of short fruiting seaweeds clung to the rocks at the water’s edge, where the only sound breaking the stillness was the water gently lapping on the shore, while the seaweed danced slowly to the rhythm of the waves.

“Jelly Bags” Seaweed at Port Eynon

"Jelly Bags" seaweed: Fucus spiralis Linnaeus (also known as "Jelly Bags" seaweed, Spiral Wrack, and Flat Wrack) showing numerous swollen reproductive bodies at the ends of the fronds, on Port Eynon beach, Gower, South Wales, UK (1)  

A couple of things were especially interesting about the Spiral Wrack on Port Eynon beach late in June. The first was the abundance of it and the profusion of the yellow reproductive bodies (scientific name receptacle, common name jelly bags). The second was the variety of sizes, shapes, and different stages of development  of these receptacles – and the presence of a number of unusual structures that can be classified as abnormal.

Spiral Wrack (Latin name Fucus spiralis Linnaeus; alternative common names Flat Wrack and Jelly Bags) is a common British seaweed. It lives in the mid-shore zone below the Pelvetia canaliculata zone (Channelled Wrack) of the upper shore, and above the Fucus vesiculosus (Bladder Wrack) and Acophyllum nodosum (Egg or Knotted Wrack) zones of the lower shore. It is exposed to the air for long periods of time between high and low tides. This alga is hermaphrodite with male and female reproductive structures on the same individual. 

The receptacles of Spiral Wrack are developed as swollen tips, often bifurcate or forked, at the ends of the fronds. Cryptostomata, that elsewhere on the fronds remain as sterile pits containing only hairs, develop in this location as fertile conceptacles that produce both male and female gametes.  Typically receptacles are broadly ellipsoidal to almost spherical and when full, ripe, and full of mucilage, are sometimes called jelly bags

On some fronds there are  also smooth, elongated, swollen structures without the small protruberances and pores that are seen on receptacles. Examples of these can be seen well in Photograph 5. This unusual feature looks like a blister; and specimens of Fucus spiralis with blistered fronds are, apparently, not uncommon. These blisters are not to be confused with air bladders – like the ones found in Fucus vesiculosus. They are instead an irregularity or abnormality, with varying shape and size, thought to be due to some adverse conditions in the environment. They lack the regular, defined, shape of an air vesicle which is inherent in the structure of seaweeds such as Bladder Wrack and Egg Wrack. Perhaps recent encroachment by sand and partial burial in this part of the beach has stressed a seaweed that is normally free to float upwards in seawater while attached to rocks.

“Jelly Bags” seaweed might also be good for the feet. Walking barefoot through the squelching masses could have a certain therapeutic effect (if you don’t slip over first). However, for the most benefit, soaking the feet with a few handfuls of the jelly bags in a bucket of hot water and salt is traditionally thought to be an efficaceous treatment for corns!

Click her for more posts about Spiral Wrack on Jessica’a Nature Blog:

Flat or Spiral Wrack from Chapmans Pool

Three brown seaweeds: Furbelows, Sea Belt, and Spiral Wrack from Studland Bay in spring 

Seaweed on Gower beaches: Fucus spiralis Linnaeus (also known as "Jelly Bags" seaweed, Spiral Wrack, and Flat Wrack) showing numerous swollen reproductive bodies at the ends of the fronds, on Port Eynon beach, Gower, South Wales, UK (2)

Fucus spiralis Linnaeus (also known as "Jelly Bags" seaweed, Spiral Wrack, and Flat Wrack) showing a close-up of the swollen receptacles at the ends of the fronds, on Port Eynon beach, Gower, South Wales, UK (3)

Jelly Bags seaweed drying out between tides: Fucus spiralis Linnaeus (also known as "Jelly Bags" seaweed, Spiral Wrack, and Flat Wrack) showing the swollen receptacles at the ends of the drying fronds, on Port Eynon beach at low tide, Gower, South Wales, UK (4)

Spiral Wrack receptacles and blisters: Fucus spiralis Linnaeus (also known as "Jelly Bags" seaweed, Spiral Wrack, and Flat Wrack) showing the swollen reproductive receptacles in various stages of development, and elongated blisters which are not reproductive in function, on Port Eynon beach, Gower, South Wales, UK (5)

View of Port Eynon looking north-east, showing Fucus spiralis drying out on rocky outcrops and sand exposed at low tide, Gower, South Wales, UK (6)

Spiral wrack at Port Eynon: View of Port Eynon looking north from the shore by the Salt House, showing Fucus spiralis just exposed by the ebbing tide, Gower, South Wales, UK (7) 

Seaweed reflecting the setting sun at Port Eynon: Detail of Fucus spiralis L. (Spiral Wrack, Flat Wrack, or "Jelly Bags") wet and glowing golden in the setting sun, at Port Eynon, Gower, South Wales, UK (8)

Close-up of Fucus spiralis L. (Spiral Wrack, Flat Wrack, or "Jelly Bags") wet and glowing golden in the setting sun, at Port Eynon, Gower, South Wales, UK (9)

COPYRIGHT JESSICA WINDER 2011

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Flat or Spiral Wrack from Chapmans Pool

Common British seaweeds picture: An arrangement of Flat or Spiral Wrack, Fucus spiralis L., from Chapman's Pool, Dorset, UK, on the Jurassic Coast World Heritage Site (P1100394aBlog1) 

I’ve talked about Flat or Spiral Wrack (Fucus spiralis Linnaeus) before but wasn’t able to show a good photograph of one of its defining features. Getting close-ups of details on the seashore is sometimes impossible – without lying full-length face-down in wet seaweed. So the last time I was on the beach I collected a few fronds of Flat Wrack, from the extensive beds of Fucoids that covered the flat rock platform on the eastern shore of Chapmans Pool, and took them home to get the photographs that I wanted in comfort.

The pictures above and below illustrate the way that the swollen granular reproductive bodies at the ends of the fronds in this species have a unique flat border – like a seam – around the edge. You can see this border both flat-on and edge-on in the photographs. In other characteristics Flat or Spiral Wrack could be mistaken for another species of Fucoid brown seaweed but it is the only one with this particular characteristic.

Seaweed close-up photograph: Detail of Flat or Spiral Wrack, Fucus spiralis L., from Chapmans Pool, Dorset, UK - part of the Jurassic Coast (P1100402aBlog2) 

The rock platform on the eastern edge of Chapmans Pool in June was covered in an olive green carpet of short Fucoid seaweeds including, Toothed Wrack, Bladder Wrack, and Flat or Spiral Wrack.

Seaweeds photograph: View of the seashore at Chapman's Pool with a rock platform covered with Flat Wrack and other Fucoid seaweeds, in Dorset, UK, on the Jurassic Coast World Heritage Site (P1100262aBlog3) 

You have to look closely to see that the seaweed bed is composed of all the different types of weed, growing together, and overlapping each other in a complex natural mosaic pattern.

Picture of seaweeds: Closer view of Flat Wrack and other Fucoid seaweeds on a rock platform at Chapmans Pool, Dorset, UK - part of the Jurassic Coast (P1100259aBlog4) 

In the picture below you can see the round pea-shaped air bladders that occur in Bladder Wrack. There are fronds like this on the left side of the picture. The golden yellow-green reproductive bodies on the forked tips of the Flat Wrack are quite distinct elsewhere in the photograph. Both seaweeds have a central midrib along the fronds. 

Previously, Flat or Spiral Wrack was discussed in the earlier post Three brown seaweeds: Furbelows, Sea Belt & Spiral Wrack from Studland Bay in spring.

Seaweeds close-up photograph: Detail of Flat Wrack and other Fucoid seaweeds on a rock platform at Chapmans Pool, Dorset, UK - part of the Jurassic Coast (P1100264aBlog5) 

Revision of a post first published 5 June 2010

COPYRIGHT JESSICA WINDER 2011

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Three brown seaweeds: Furbelows, Sea Belt & Spiral Wrack from Studland Bay in spring

Common British seaweeds picture: Furbelows seaweed, Saccorhiza polyschides, washed ashore onto the sandy beach at Studland Bay, Dorset, UK, on the Jurassic Coast World Heritage Site (P1070086Blog1) 

Seaweeds usually start off life attached to rocks. Although Studland Bay is famous for its beautiful fine, clean sand, there are rocks to the west of the bay near Old Harry Rocks, and also the artificial substratum of what is locally termed the Training Bar. The Training Bar runs from the junction of Shell Bay and Knoll Beach (both are parts of Studland Beach) seawards in an approximately south-westerly direction. It is signposted with beacons on poles. Its purpose is to guide boats safely into the narrow entrance to Poole Harbour by the Sandbanks Ferry.

Seaweed becomes detached from the rocks for many reasons but most commonly due to strong wave action in stormy weather. The weed then floats around and often gets washed ashore. Because the weed may have been swilling around for a considerable time, the condition may be poor when it is found on the beach.

Most of the time the quantities of weed are moderate, scattered and impermanent  – it gets washed out to sea on the next tide. Occasionally vast banks of weed accumulate and do not disperse. If this happens, the National Trust (who own the beach) have hit on the novel idea of bagging it up and selling it as fertiliser for the garden. It makes excellent enrichment for the soil. For centuries, people have gathered seaweed for this purpose. In Alderney in the Channel Islands, for example, you can find evidence of the former wrack-gathering activities in the cobbled ramps that lead down to the beaches; these were constructed for the carts to get down to the shore. 

The top picture shows the commonly occurring kelp called Furbelows, Saccorhiza polyschides(Lightfoot) Batters, washed up at Studland Bay, Dorset. It is one of the largest brown seaweeds or Phaeophyceae. It has long strap-like leathery fronds. The stalk is short, flat and typically has a wavy ruff or frill either side of it as you can see in the picture below. Sometimes the stalk is twisted at the base. The holdfast at the base frequently has a warty and bulbous hemispherical appearance as well as rootlets. Lots of plants and animals prefer to settle here on both stalk and holdfast. The specimen below has red seaweeds attached to it. 

Common British seaweed photograph: Furbelows kelp, Saccorhiza polyschides (Lightfoot), showing wavy-edged lower stem and holdfast, washed up at Studland Bay, Dorset, UK - part of the Jurassic Coast World Heritage Site (P1070088Blog2)

Sea Belt or Poor Man’s Weather GlassLaminaria saccharina (Linnaeus) Lamouroux, is another large brown kelp but is easily distinguished from Furbelows. The frond is often a single blade and is has a crinkly surface that looks like that old-fashioned fabric known as seersucker.

Common British seaweeds photograph: Sea Belt or Poor Man's Weather Glass, Laminaria saccharina (Linnaeus) Lamouroux, washed up onto the sandy shore at Studland Bay, Dorset, UK - part of the Jurassic Coast (P1070094Blog3).

The stem of Sea Belt is short and slender as you can see in the photograph below. There are no lateral frilly edges. The holdfasts are a series of intertwined rootlets and there is no large bulbous structure.

Common British seaweeds photograph: Stems and holdfasts of Sea Belt, Laminaria saccharina (Linnaeus) Lamouroux, washed up on the sandy shore at Studland, Dorset, UK - part of the Jurassic Coast (P1070110Blog4)

You can find more pictures and information about these two kelps in a previous post – click here for Kelps at Kimmeridge Bay.

Studland Bay seaweed photograph: Flat or Spiral Wrack, Fucus spiralis Linnaeus, washed up on the sandy shore at Studland Bay, Dorset, UK - part of the Jurassic Coast World Heritage Site (P1070122Blog5)

One of the smaller brown seaweeds is Flat or Spiral Wrack, Fucus spiralis Linnaeus, pictured above and below. Like Bladder Wrack and Toothed Wrack it has a central midrib – but it doesn’t have any air bladders and the edges of the fronds are smooth. One of its supposed characteristics, and the one from which it gets the name Spiral Wrack, is the tendency of the fronds to twist -but you can’t rely on this feature alone for identification. When the forked tips of the fronds swell with reproductive products, they are lighter in colour and have a granular appearance. However, these swellings have a distinct longitudinal ridge or border around their edge which is a continuation of the blade or frond. This is one of the diagnostic features for the species.

There are more detailed pictures and explanations about Flat or Spiral Wrack click here for Flat or Spiral Wrack from Chapman’s Pool.

Common British seaweeds photograp: Flat or Spiral Wrack, Fucus spiralis Linnaeus, showing reproductive bodies at frond tips; Studland Bay, Dorset, UK - part of the Jurassic Coast (P1070123Blog6) 

Revision of a post first published 4 June 2009

COPYRIGHT JESSICA WINDER 2011

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