Rock Pooling Destination: Porth Seal, Isles of Scilly, UK. April 2013

The rock pools at Porth Seal vary with those in the upper shore characterized by the green seaweeds Cladophora and Ulva spp; whilst mid shore pools are dominated by encrusting coralline algae and a variety of red and brown seaweeds; further down the shore brown seaweeds, such as Bifurcaria bifurcata and Himanthalia elongata, become more prolific within the coralline pools with red seaweeds occupying the understory. Above the pools is a mosaic of fucoids, osmundea, grazing molluscs and barnacles.


Spring storms had washed large quantities of seaweed up onto the shore where it formed mounds marking the successive strand lines and filled many of the higher to mid shore pools. The presence of the decomposing seaweed in the pools caused the water to become de-oxygenation and stagnant. The spring storms also deposited sand into many of the higher and mid shore pools that formed a thick layer over the pre-existing coralline algae and facilitated the growth of ephemeral green seaweeds such as Cladophora spp. In comparison to April 2012 these pools appeared to contain less mobile fauna (fewer gastropods and no sea hares were observed).

Below are photographs of some of the organisms in these pools:


                                        

Spring storms had washed large quantities of seaweed on the shore.

The washed up seaweed filled many of the higher to mid shore pools.

 The presence of the decomposing seaweed in the pools caused the water to become de-oxygenation and stagnant.

The rocky shore is comprised of bed rock and boulders interspersed with rockpools and gullies. Biotope classification:  LR.MLR (Moderate energy littoral rock).

 The mid and upper shore is charecterised by mosaics of barnacles and fucoids.

Barnacles

The shallow rock pools of the upper and mid shore that have not been smothered by sand or seaweed are charecterised by corallinacea crusts. Biotope classification:   

LR.FLR.Rkp.Cor (Coralline crust-dominated shallow eulittoral rockpools).

A corallinacea crust dominated rock pool with Coral weed (Corallina officinalis), Beadlet anemone (Actinia equina), Topshell (Gibbula umbilicus) and a blenny. 

A beadlet anemone (Actinia equina)

A mussel (Mytilus edulis)

A coralline pool dominated by ephemeral green seaweeds; coralline crusts can still be seen beneath the sand.

Sand covers the Corallinacea crust and the pool is dominated by ephemeral green seaweeds.

Mid shore pools are less effected by the deposition of seaweed and contain more seaweed species.

Coral weed (Corallina officinalis) 

Ceramium Spp 

Codium fragile 

Codium fragile on the mid shore.

 Bushy rainbow wrack (Cystoseira tamariscifolia).

Cladophora rupestris

Calliblepharis jubata

Polychaetes

Daisy anemone (Cereus pedunculatus)



Gem anemone (Aulactinia verrucosa)

  Bifurcaria bifurcate dominates certain pools of the lower shore. Biotope classification: LR.FLR.Rkp.Cor.Bif Bifurcaria bifurcata in shallow eulittoral rockpools.

Serrated wrack (Fucus serratus) dominates the lower shore with red seaweeds beneath its understory. Biotope claasification: LR.MLR.BF.Fser.R (Fucus serratus and red seaweeds on moderately exposed lower eulittoral rock).

Red seaweeds form mosaics amongst the serrated wrack (Fucus serratus). Sand binder (Rhodothamniella floridula) forms a truf whilst Osmundea spp occurs within crevices and cracks of the boulders.

Osmundea spp

A limpet (Patella vulgata) and barnacles

Grape pip weed (Mastocarpus stellatus)

Corallinacea crust, Corallina officinalis , Bifurcaria bifurcata, The limpet Patella vulgata and snakelocks anemone (Anemonia viridis) occur on a boulder amongst Serrated wrack (Fucus serratus).

Corallinacea crust occurring on the lower shore.

Coral weeds (Corallina spp ) form dense turfs on the lower shore.

Dahlia anemone (Urticina felina)

Purse sponge (Grantia compressa)

Further down the shore Thong weed (Himanthalia elongata) occurs amongst red seaweeds.

Rock Pooling Destination: Seapalling, Norfolk, England

Rock Pooling Destination: Seapalling, Norfolk March 2013

The shore at Seapalling is influenced by a series of artificial sea defenses that have changed the dynamics of the shore to produce multiple bays comprised of sand with shingle berms in between. 

After a week of spring storms a variety of subtidal fauna had been washed up in the strand line:

Thousands of razor shells  washed up on the shore.

Common starfish (Asterias rubens) in an intertidal pool. Note the wide tubular shapes also present- these are the insides of the razor shells that had been washed up on the shore.

A subtidal polychaete worm (opheliidae).

A subtidal seacucumber (Thyone spp.)

A subtidal anemone (Possibly Urticina spp).

The dorsal side of a sea mouse (Aphrodita aculeata)

The ventral side of a sea mouse (Aphrodita aculeata)

Crabs

A female shore crab (carcinus maenas) with eggs referred to by fisherman as gravid or buried.

A squat lobster (galatheoidea)

A slipper limpet (Crepidula fornicata)

Common whelk shell with a slipper limpet  (Crepidula fornicata) living inside.

A mussel (Modioulus spp.) 

Rocky shore communities of the artificial sea defenses:

Barnacles, periwinkles, limpets, sparse dog whelks and fucoids charecterise this habitat. 

Biotope classification: LR.MLR (Moderate energy littoral rock).

Rocky shore communities have formed on the artificial sea defenses; barnacles, Limpets (Patella vulgata) and the small periwinkle (Melarhaphe neritoides ) charecterise the equivalent upper and mid shore of the sea defenses. 

 Barnacles and periwinkles occur in a distinct band on the sea defenses.

A barnacle 

The common starfish (Asterias rubens) and beadlet anemones (Actinia equina). A number of  common star fish were washed up during the recent storms and were found seeking refuge amongst the sea defenses.

Common starfish (Asterias rubens) that have been washed in take refuge in the shady pools of the artificial  sea defenses.

The common sunstar (Crossaster papposus)

Ulva spp and Porphyra spp are ephemeral red and green seaweeds characteristic of mid shore communities influenced by sand scour.

On extreme low tides the blue mussel (Mytilus edulis) can also be observed (photo taken in 2012)

Serrated wrack (Fucus serratus) occurs on the lower shore

Edible crab (Cancer pagurus) and common starfish (Asterias rubens) seek refuge in the crevices between the stones of the sea defenses after being washed up in the recent storms. 

The common starfish (Asterias rubens) and razor shells washed up by the recent storms.