Sea Spurge on Llangennith Burrows, Rhossili

Sea Spurge, Euphorbia paralias Linnaeus, on the sand dunes of Llangennith Burrows backing onto Rhossili Bay, Gower, South Wales, UK (1) 

The deep red stems of Sea Spurge on the sand dunes caught my eye this spring. These plants were found at Llangennith Burrows which backs onto the northern end of Rhossili Bay, Gower. It was rather a dull overcast day so it was especially cheering to see these patches of bright colour. Euphorbia paralias Linnaeus must be a very drought resistant plant to survive in this location.

Sea Spurge, Euphorbia paralias Linnaeus, on sand dunes of Llangennith Burrows backing onto Rhossili Bay, Gower, South Wales, UK (2)

There were small groups of Sea Spurge just putting on a growth spurt with the advent of a little warmer weather and lots of rain. They were mostly established around the edges of the Marram grass which topped the dunes. I saw this plant at the extreme eastern end of Whiteford Sands too.

It will be interesting to see what this plant looks like in a month or so when it is fully grown and in flower – and I visit Gower again.

Sea Spurge, Euphorbia paralias Linnaeus, on sand dunes at Llangennith Burrows backing onto Rhossili Bay, Gower, South Wales, UK (3)

Revision of a post first published 10 May 2009

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Lug Worms at Whiteford Sands

Lug worm casts on the beach: Thousands of huge lug-worm casts (probably from the marine worm Arenicola marina Linnaeus), looking like a vast field of walnut whips, stretching as far as the eye can see at Whiteford Point, Gower, South Wales (1)

Lug-worm casts  extending like a vast field of walnut whips as far as the eye can see at Whiteford Point, Gower in South Wales. These casts are made by the marine worm Arenicola marina Linnaeus.

Lug Worm blow hole and cast: Blow hole and spiral cast of the marine polychaete Blow Lug or Lug Worm, most probably Arenicola marina Linnaeus, on the shore at Whiteford Sands, Gower, South Wales (2)

Blow hole and spiral cast of the Blow Lug or Lug Worm – each representing opposite ends of the U-shaped tube occupied by the worm in the sand.

Blow hole of the marine polychaete Lug Worm Arenicola marina Linnaeus in the shore sediments at Whiteford Sands, Gower, South Wales (3)

Blow hole of the Lug Worm in sediments of Whiteford Sands in Gower. The head end of the worm lies beneath this hole and the worm eats the sand in order to get nutrients from the detritus and micro-organisms that it contains.

The spiral worm cast of excreted sediments from the marine polychaete Arenicola marina Linnaeus, the Blow Lug or Lug Worm, at Whiteford Sands, Gower, South Wales (4)

The tail end of the worm lies beneath the spiral worm cast that is composed of the excreted sediments after they have passed through the worm’s gut.

In the picture below you can see from the widely spaced distribution of blow holes and worm casts that Lug Worms on the beach at Whiteford Sands are not so abundant as at Whiteford Point (illustrated at the top of this post)because the sediments are drier, more sandy, less muddy, and therefore with a smaller organic component.

Lug Worm holes and casts on the sand: The widely spaced casts and blow holes of Lug Worms, Arenicola marina Linnaeus, on the drier and sandier shore of Whiteford Sands, Gower, South Wales in marked contrast to the intense colonisation of wetter and muddier shore sediments by Whiteford Point (5)

Hidden from view, of course, are the burrows themselves. These can only be truly observed in a laboratory observation using a glass-sided tank. As we saw yesterday (post of 9 July 2011), these or similar worms and their burrows have been around for millions of years as evidenced by trace fossils such as those found in the Jurassic Arenicolites Beds at Ringstead on the Jurassic Coast.

For more pictures showing the living Lug Worm itself, and video clips of Lug Worms click here for the ARKive web site.

Revision of a post first published 1 May 2009

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Pebbles at Rhossili Part 1

Pebbles with pastel colours like sugared almonds on the beach at Rhossili Bay, Gower, South Wales, UK (1)

Looking like lots of pastel-coloured sugared almonds, these pebbles from Rhossili Bay reflect not only the immediate solid geology of the area but also the surface geology relating to former glaciation events.

The pale blue-grey smooth stones are Carboniferous Limestone which outcrops in the two headlands of the bay at Worms Head and Burry Holms. The pink and red relatively coarse-grained stones are derived from the Old Red Devonian Sandstone which forms the basis of Rhossili Down at the head of the bay. Other stones of all sorts, originally from places far away, have been delivered to the location as they melted out of the bottom of an ice sheet or glacier over 10,000 years ago.

Pebbles like candy on the beach: Pebbles with pastel colours like sugared almonds on the beach at Rhossili Bay, Gower, South Wales, UK (2)

Revision of a post first published 26 March 2009

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Rhossili ripplescapes Part 1

Sand ripple patterns on the beach: Ripple patterns on Rhossili beach, Gower, West Glamorgan, New Year's Day 2010 (1) 

New Year’s Day 2010 was a fabulous day to be in Gower. Not only did the sun shine brightly from a clear blue sky on the frostiest and chilliest of days but the sea itself had decorated the seashore with wonderful, sharply-ridged ripple patterns of hard wet sand. This ornamentation was spread over extensive areas at  the Llangennith end of the beach, close to the island of Burry Holms, forming not seascapes or landscapes but unique ripplescapes. 

 Natural patterns in the sand: Ripple patterns on Rhossili beach with the island of Burry Holms in the background, Gower, West Glamorgan, New Year's Day 2010 (2)

Sand ripple patterns at Rhossili: Ripple patterns on Rhossili beach with Rhossili Down in the background, Gower, West Glamorgan, New Year's Day 2010 (3)

Revision of a post first published 3 January 2010

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Banded Wedge Shells at Rhossili

Banded Wedge Shells: Paired empty valves of Banded Wedge Shell on sand at Rhossili, Gower, South Wales, U.K. (1)

Like colourful butterflies on the sand, the paired valves of the Banded Wedge Shell are one of the common and attractive finds on Rhossili beach, Gower. On the outer surface they are often bright yellow while the inner surface is frequently a lovely lilac or purple colour.

Banded Wedge Shells: Inner surface of paired valves of Banded Wedge Shell on the sand of Rhossili beach, Gower, South Wales.

The empty shells can occur in large numbers on the strandlines but, if you look carefully underfoot at low tide level, you can find the animals alive in the wet sand. Typically, part of the shell protrudes above the surface; it may be obscured by sand.

Banded Wedge Shell: A living Banded Wedge Shell part-buried in wet sand at low tide level at Rhossili, Gower, South Wales.

The texture of the sand varies from fine and compact with a smooth surface texture to patches where the sand grains appear coarser and the surface is an uneven texture looking a bit like lumpy porridge.

Living Banded wedge Shell: Living specimen of Banded Wedge Shell (Donax vittatus da Costa) protruding from coarse wet sand at low tide level at Rhossili, Gower, South Wales, U.K. (4)

Occasionally, the Banded Wedge Shells are found entirely exposed, lying in the surface water. In the picture below you can see the soft translucent fleshy foot and the siphons partially extended between the hard shiny shell. The large muscular foot is used to rapidly draw this bivalve down into the safety of the wet sediments if it is disturbed – either by the incoming surf or passing feet.

Live Banded Wedge Shell on sand: A living Banded Wedge Shell, Donax vittatus (da Costa), with fleshy foot and siphons partially extended, in surface water on sand at Rhossili, Gower, South Wales, U.K. (5)

If you wait patiently and watch a partially buried Banded Wedge Shell, you may witness the cyclical retraction and subsequent extension of the paired tubular siphons as they squirt out water. In the photograph below the siphons are fully extended and have just evacuated.

Banded Wedge Shell alive showing siphons: Living Banded Wedge Shell with the siphon tubes fully extended on the lower seashore at Rhossili, Gower, South Wales, U.K. (6)

Revision of a post first published 29 August 2009

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Stranded starfish at Rhossili Bay

Starfish at Rhossili Bay: Stranded starfish near Burry Holms at Rhossili, Gower, South Wales, U.K. 15th August 2008 (1)

Thousands of starfish were stranded by high tides and stormy seas one August at Rhossili Bay on the  Gower Peninsula. These voiolent natural events happen from time to time in the ecology of the seashore. Although it is sad to see so many marine and seashore creatures perishing at once, it is all part of the bigger picture. These animals become part of the food chain for other creatures – the more obvious larger ones like crabs and birds and the smaller invertebrates like the sandhoppers.

These Common Starfish, Asterias rubens Linnaeus, on the sandy shore formed a virtual carpet of orange, pink, red, purple and every colour in between. Star shapes and contorted versions of them. Rough spikey textures on vividly coloured upper surfaces; and soft radiating rows of tube feet on paler lower surfaces. Spread across a wide strandline in an almost continuous mosaic pattern – interspersed with razor and other seashells and empty tests of sea urchins. The occasional crab feasting on the remains; raucous groups of big seabirds picking over the remains.

Common British starfish: Stranded starfish near Burry Holms at Rhossili, Gower, South Wales, U.K. 15th August 2008 (2)

Stranded Common Starfish (Asterias rubens Linnaeus) near Burry Holms at Rhossili, Gower, South Wales, U.K. 15th August 2008 (3)

Stranded Common Starfish (Asterias rubens Linnaeus) near Burry Holms at Rhossili, Gower, South Wales, U.K. 15th August 2008 (4)

Starfish washed ashore: Stranded Common Starfish (Asterias rubens Linnaeus) near Burry Holms at Rhossili, Gower, South Wales, U.K. 15th August 2008 (5)

Dead pink starfish: Stranded Common Starfish (Asterias rubens Linnaeus) near Burry Holms at Rhossili, Gower, South Wales, U.K. 15th August 2008 (6)

Crab eating starfish: Edible Crab (Cancer pagurus Linnaeus) eating dead stranded Common Starfish (Asterias rubens Linnaeus) near Burry Holms at Rhossili, Gower, South Wales, U.K. 15th August 2008 (7)

Upside-down stranded Common Starfish (Asteria rubens Linnaeus) still clinging to life near Burry Holms at Rhossili, Gower, South Wales, U.K. 15th August 2008, showing extended tube feet (8)

A multi-coloured carpet of stranded starfish (Asterias rubens Linnaeus) on the sandy strandline near Burry Holms at Rhossili, Gower, South Wales, U.K. 15th August 2008 (9)

Revision of a post first published 2 October 2009

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The Common Whelk (1)

Common Whelk: Pink shelled living specimen of Common Whelk, Buccinum undatum Linnaeus, on rocks at Burry Holms, Rhossili, Gower, South Wales, U.K. (1)

A pink-shelled living specimen of Common Whelk, Buccinum undatum Linnaeus, washed onto the rocks of Burry Holms on Rhossili Bay, Gower, after stormy winter weather.

Until a couple of years ago, the only place where I had seen the meaty part of a Common Whelk was at the fishmongers. I had no idea that the living animal could be such a lovely creature. The specimen at the top of this post unexpectedly had a beautiful pink shell. Its living flesh was white with black irregular speckles – particularly concentrated at the head end. You can see the two horns or cephalic tentacles sticking out on each side of the head.

On the back of the large muscular white foot is the brown horny operculum which is the lid with which it seals itself inside the shell when it retreats. Protruding from the front end of the shell, just over the head, is the tubular siphon through which is takes in water.

Whelk shell with pattern of growth lines: Brown and cream coloured empty Common Whelk shell, Buccinum undatum L., showing the pattern of growth lines, from Rhossili Bay, Gower, South Wales, U.K. (2)

Mostly, in the past, I have just found the empty shells on the beach. The colour can be quite variable. The close-up photograph above shows a fairly typical brown and cream coloured shell and it is possible to see some details of the shape and sculpturing of the shell. At a later date I will provide some specific details of how to accurately identify the shell. I will also talk a bit about the life history of the Common Whelk.

The picture below shows a group of empty shells in various colours from cream and white, to orange and a dark blue/black. These were found on Whiteford Sands in Gower.

Different coloured Whelk shells on a sandy beach: A group of white, orange and dark blue empty Common Whelk shells, Buccinum undatum L., on Whiteford Sands, Gower, South Wales, U.K. (3)

Revision of a post first published 7 July 2009

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