Sunday, 28 June 2015

Rockpooling Destination: Revisit West Penwith, April 2015

The rocky shore is a high energy environment comprised of boulders and bedrock with rock pools, crevices and gullies.
he rocky shore is comprised of boulders and bedrock with rockpools, crevices and gullies. Habitat classification: LR.HLR (High energy littoral rock) EUNIS: A1.1 , LR.FLR.Rkp (Rockpools) EUNIS:A1.41 and LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock) EUNIS: B3.11.

The high energy environment of the shore leads to an extended lichen zone, that descends over much of the boulder field, which apart from Littorinids is relatively barren. Patches of lichens extend further down into the barnacle communities, which dominate from the upper to lower shore, interdispersed by shallow coralline rockpools in the mid shore, and deeper cobble filled rockpools on the lower shore. As the low tide mark is reached wave tolerant seaweeds lace the gullies.

Habitat classification:

LR (Littoral rock)

LR.HLR (High energy littoral rock)
LR.FLR (Features of littoral rock)
Biotope complex

LR.HLR. MusB (Mussel and/or barnacle communities)
    LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock).

LR.FLR.Rkp (Rockpools)

LR.FLR.Lic.Ver (Verrucaria Maura on  littoral fringe rock)

LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock)
LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools)

LR.FLR.Rkp.Cor.Bif (Bifurcaria bifurcata in shallow eulittoral rockpools)

Below are images of the organisms you may encounter in these habitats:

Lichens characterise the supralittoral and littoral fringe with periwinkles among the boulders. The littoral fringe of the boulder field does not support vast expanses of tar lichen (Verrucaria maura) which covers more stable bedrock of the littoral fringe, however, the mobile species found among the boulders on the littoral fringe are consistent with that of the V. maura biotope.  Habitat classification: LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock) and LR (Littoral rock).
Examples of lichens found in the supralittoral:

Periwinkles are the most prolific mobile fauna of the boulder field, where they seek refuge within crevices. Rough periwinkles (Littorina compressa nigrolineata) and occasional barnacles. Habitat classification: A possible variant of LR.FLR.Lic.Ver (Verrucaria Maura on  littoral fringe rock).
                           Littorina saxatilis agg
 Littorina compressa var. nigrolineata

Bedrock on the mid shore support barnacle communities and coralline rockpools. Within the barnacle communities beadlet anemones and increased numbers of gastropods can be found within the crevices, whilst limpets aggregate on the leeward sides of the rock and Lichina pygmaea forms tufts on the rock tops.
Habitat classification: LR.HLR. MusB (Mussel and/or barnacle communities) EUNIS: A1.11 and LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools) EUNIS: A1.411.

The lichen , Lichina pygmaea  forms small bushy growths on the boulders, often supporting increased numbers of small periwinkles (Melarhaphe neritoides). In April the lichen appears somewhat greenish, by comparison to previously in the year. (See blog post

A young crab feeds upon a M. neritoides

Barnacles and limpets (Patella sp)

Barnacles and M. neritoides
As the lower shore is reached the abundance of barnacles and Patella depressa increases.

The rockpools on this high energy shore are characterized by the presence of coralline seaweeds that make the rockpools appear as if they have been covered in a layer of pink paint. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools) EUNIS: A1.411.

Brown seaweeds that were absent in October, now grow in the rockpools. (See blog post:

China limpet (Patella ulyssiponensis)

P. ulyssiponensis

P. ulyssiponensis
P. ulyssiponensis interacting.
Common blue mussels (Mytilus edulis)  and Corallina officinalis occur within a crevice of a coralline rockpool.
A blenny and limpet.
Deeper rockpools support a higher diversity of seaweed species including, a greater abundance of Corallina officinalis and the brown forking weed (Bifurcaria bifurcata). Habitat classification: LR.FLR.Rkp.Cor.Bif (Bifurcaria bifurcata in shallow eulittoral rockpools) EUNIS: A1.4113
The invasive Sargassum muticum

Chondrus crispus

Chondrus crispus

Anemonia viridis
Grey topshell (Gibbula cineraria)

Monday, 22 June 2015

Rockpooling destination: Revisit Penberth April, 2015

The shore comprises a narrow cove with boulders lining either side of a slipway. There is a river that forms a small waterfall on the upper shore before flowing beneath the boulders to the sea.

The cove experiences high wave exposure and is characterized by an extended splash zone with lichens and periwinkles. Barnacles characterise the mid and lower shore,  with an increased abundance of barnacles, limpets and robust seaweeds towards the low water mark. There are relatively small gravel filled rockpools beneath the boulders and coralline rockpools at the cliff edges.

The tide was lower than during previous visits allowing  a greater variety of lower shore red seaweeds to be photographed. However, time prevented me from looking at the fresh water influenced habitats of the upper shore which, I have photographed previously. 
See blog post:

Below are images of organisms you may encounter whilst rockpooling in these habitats:

The rocky shore is comprised of boulders and a slip way. A variety of Yellow and grey lichens characterise the supralittoral.  Habitat classification: LR.FLR.Lic (Lichens on supralittoral and littoral fringe rock) EUNIS:B3.111


Plants also occur between the boulders in the supralittoral.

Black tar lichen (Verrucaria maura) markes the transitions from the supralittoral to the littoral fringe habitats. Habitat classification: 
LR.FLR.Lic.Ver (Verrucaria Maura on littoral fringe rock) EUNIS: B3.113
Sparse barnacles occur within the V.maura biotope.
Limpets (Patella vulgata), Periwinkles (Littorina spp.) and sparse barnacles.

Littorina compressa nigrolineata 

Barnacles and periwinkle

Small periwinkles (Melarhaphe neritoides)

Small red mites scurry across the rocks.

An ant on the upper shore. There are a variety of terrestrial insects that you can come across on the shore, especially during the summer months. However, this component of the intertidal ecology is often over looked.

An ant on the top of a coralline rock pool.

Snakelocks anemone (Anemonia viridis) in a coralline rockpool. The rockpools of the shore are confined to the bedrock of the cliff edges, and mainly comprise narrow stretches of water. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust-dominated shallow eulittoral rockpools) EUNIS A1.411

Snakelocks anemone (Anemonia viridis)

China limpets (Patella ulyssiponensis) within a coralline rockpool. 

Thick topshell (Osilinus lineatus)

The lichen, Lichina pygmaea occurs in patches among the barnacles communities of the upper shore. Habitat classification: LR.HLR. MusB (Mussel and/or barnacle communities), EUNIS: A1.11.
The boulders of the mid shore support a community of barnacles, limpets, dog whelks and where conditions allow seaweeds. Habitat classification: LR.HLR. MusB (Mussel and/or barnacle communities), EUNIS: A1.11.
Between the boulders beadlet anemones (Actina equina) and small individual seaweeds can also be found.
Spiral wrack  (Fucus spiralis)
Several of the boulders have patches of a dark green lichen/algae?
Dog whelks (Nucella lapillus)

On the lower shore the density of barnacles increases and Patella depressa is found.
Barnacles on the lower shore.
Volcano barnacles (Balanus perforatus) beneath a boulder overhang if the lower shore.

Grey topshell (Gibbul cineraria) on the lower shore.

A low turf of coralline algae.
As the lower shore is reached there is a proliferation of wracks and red seaweeds. Habitat classification: LR.HLR.FR.Him (Himanthalia elongata and red seaweeds on exposed to moderately exposed lower eulittoral rock).

Osmundea spp and short Corallina spp turfs

Throng weed (Himanthalia elongata) over grows a turf if red seaweeds at the low tide mark.

A variety of red seaweeds co occur in close proximity.
Mastrocarpus stellatus grows among the stypes of Himanthalia elongata.

Chondrus crispus and Osmundea spp

Lomentaria articulata

Young fucoids, greens and plumose reds drape a boulder at the low tide mark.

A seal sleeps whilst I rockpool around the shore.