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.

Egg Wrack Seaweed at Saints Rest Beach

Egg Wrack with fruiting bodies

Around the shores of the Bay of Fundy on the northeast Atlantic coast of Canada, where the highest tides in the world are experienced, the inter-tidal zone is correspondingly extensive. Where the beaches are bordered by steep-sided rock, seaweed grows to a great height and the fronds hang down in long curtains to meet seashore.

These photographs show one of the beaches where this can be seen: Saints Rest Beach in New Brunswick on the edge of Irving Nature Park. It was a rather bleak wet day in early June this year when the wrack, Egg Wrack (Ascophyllum nodosum), was sporting short, contrastingly yellow receptacles. These are stalked, warty, fruiting structures that release motile sex cells before falling off. Some of the stalks also bear attached the red seaweed Polysiphonia.

Parting the hanging strands of weed reveals the rock beneath. This is covered with encrusting pink algae and sessile barnacles. The rock itself provides evidence of the region’s glaciated past with a polished surface and striations made by the passage of ice sheets bearing a load of rocks and stones. The patchwork-patterned rock in one of the photographs is a consolidation of some of this glacial debris – possibly glacial outwash materials with interspersed layers of marine deposits.

See the earlier posts on Saints Rest Beach

… and more posts about Egg Wrack.

Egg Wrack on barnacle-covered rock

Egg wrack on a boulder of consolidated glacial outwash material

Egg wrack on glaciated rock with polished surface and striations

Thick curtains of seaweed hanging down from rocks on the Bay of Fundy

Thick curtains of seaweed hanging down from rocks on the Bay of Fundy

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