Thursday, 14 November 2013

Rock pooling destination: Penberth, Cornwall September 2013

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

The upper most shore is characterised by yellow and green lichens. Fucus ceranoides and ephermeral seaweeds characterise areas of the upper shore influenced by fresh water influx, whilst elsewhere tar lichen, barnacles, limpets and periwinkles occur. As you extend further down green ephermeral seaweeds, limpets and barnacles become more abundant with the odd dog whelk and mussel. On this visit the lower shore could not be observed but previously beadlet anemones, red seaweeds and crustaceans have been recorded.
Habitat classifications:
LR (Littoral rock)
HLR (High energy littoral rock)
FLR (Features of littoral rock)
LR (Low energy littoral rock)
Biotope complex
LR.HLR. MusB (Mussel and/or barnacle communities)
LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock).
Eph.FLR.Eph (Ephemeral green or red seaweed communities
LR.LLR.FVS (Fucoids in variable salinity)

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

LR.LLR.FVS.Fcer (Fucus ceranoides on reduced salinity eultittoral rock)

Rocky shore comprising boulders.

Lichens in the upper most part of the shore. Habitat classification: LR.FLR.Lic (Lichens on supralittoral and littoral fringe rock).

Sea ivory (Ramalina siliquosa)

Possible Parelle (Ochrolechia parella).

Anaptychia spp.

Sea ivory (Ramalina siliquosa) and other lichens.

Tar lichen (Verrucaria maura) occurs below the band of yellow and green lichens. Habitat classification: 
LR.FLR.Lic.Ver (Verrucaria Maura on littoral fringe rock).

Small periwinkles (Melarhaphe neritoides) occur within cracks and divots of the boulders.
Sparse barnacles occur with Small periwinkles (Melarhaphe neritoides).

Periwinkles aggregated between boulders where conditions are more sheltered.
Periwinkles aggregate between the boulders on the shore.

Periwinkles aggregate in the lee too of boulders on the shore.

Limpets also aggregate on the sheltered side of boulders.

Limpets (Patella vulgata) aggregate in the shelter of two boulders.

A limpet (Patella vulgata)

Meanwhile where the river brings fresh water onto the shore it influences the communities found with low salinity tolerant species  such as Fucus ceranoides and ephermeral seaweeds dominating. Habitat classification: LR.LLR.FVS.Fcer (Fucus ceranoides on reduced salinity eultittoral rock).

The water collects for form low salinity pools. Habitat classification:  FLR.Rkp (Rockpools).

Fucus ceranoides

Porphyra spp
The river soon flows beneath the boulders.

Further down on the mid to lower shore the river flows beneath the boulders and species such as the limpets, Patella depressa and mussels (Mytilus edulis) occur. Habitat classification: LR.HLR. MusB (Mussel and/or barnacle communities).

Barnacle abundance also increases.


Patella depressa

Patella depressa and barnacles

Boulders are covered in barnacles and limpets.

As the lower shore is reached red seaweeds occur beneath the boulders and extend below to form an understory.

But the tide was too high to see any more!

Seaweed washed in during winter storms had aggregated on the slip way.