Rockpooling destination: Revisit West Penwith, June 2016

The 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 rocky shore is a high energy environment comprised of boulders and bedrock with rock pools, crevices and gullies.

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, inter-dispersed 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:

Substrate	LR (Littoral rock)
Habitat	LR.HLR (High energy littoral rock)			LR.FLR (Features of littoral rock)
Biotope complex	LR.HLR. MusB (Mussel and/or barnacle communities)		LR.HLR.FR (Robust fucoid and/or red seaweed communities)	LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock).		LR.FLR.Rkp (Rockpools)
Biotope	LR.HLR.MusB.Cht (Chthamalus sp on exposed upper eulittoral rock)	LR.HLR.MusB.Sem (Semibalanus balanoides on exposed to moderately exposed or vertical sheltered eulittoral rock)		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)

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

Among the mobile boulders and bedrock of the littoral fringe are populations of rough and small periwinkles with occasional limpets on the lower littoral. In this high energy environment organisms are confined to crevices and nooks, where they are buffeted from the full force of the waves and potential dislodgement. Habitat classification:  LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock) EUNIS: B3.11

During winter storms slabs of granite were broken away from the bedrock. Now in June this rock has not yet been colonised. 

The same area of bedrock in March 2016.

The exposed uppershore bedrock is covered in dense barnacles, with crevices jammed by mussels, anemones and coralline seaweeds. Small periwinkles occur among the barnacles, seeking shelter within the dead barnacle tests. The black lichen Lichina pygmaea forms tufts on the upper rock. All these organisms are characteristic of the biotope: LR.HLR.MUSb.CHT (Chthamalus sp on exposed upper eulittoral rock) EUNIS: A1.112. Darted among this habitat are small coralline rockpools. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools) EUNIS:A1.411.

Lichina pygmaea forms tufts of varying density

During the summer months rockpools experience prolific growth of ephemeral green seaweeds.

 The distribution of the ephemeral green seaweeds can be patchy.

In many cases the ephemeral green seaweeds dominate the coralline rockpools.

Ephemeral green seaweeds come to dominate many of the shallow rockpools during the summer months.

The coralline rockpools of the mid and lower eulittoral support a greater diversity of seaweeds than the upper, including Bifurcaria bifurcata, Corallina officinalis, coralinaceae crusts and ephemeral green seaweeds, along with beadlet anemones, china limpets, flat topshells and thick topshells. Habitat classification: LR.FLR.Rkp.Cor.Bif (Bifurcaria bifurcata in shallow eulittoral rockpools) Eunis A1.4113

Bifurcaria bifurcata in a shallow coralline eulittoral rockpool

Compared to March there are a greater diversity of  ephemeral and seasonal seaweeds, including Scytosiphon lomentaria.

On the sections of moderately exposed lower shore the diversity of seaweeds on the exposed bedrock also increases.

In these areas the abundance of barnacles is lower and the abundance of topshells, anemones, limpets, fucoids and red seaweeds increase. Habitat classification: LR.MUSb.Sem (Semibalanus balanoides on exposed to moderately exposed or vertical sheltered eulittoral rock) EUNIS: A1.113.

Red seaweed 'turfs' form between damp crevices and beneath overhangs.

The highest diversity of life is still found within the rockpools and on the lower shore were there is an explosion of seaweeds!

As the subtidal pools are reached the abundance of red seaweeds and kelp increase.

Rockpooling Destination: Revisit West Penwith, December, 2015

The 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 rocky shore is a high energy environment comprised of boulders and bedrock with rock pools, crevices and gullies.

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:

Substrate	LR (Littoral rock)
Habitat	LR.HLR (High energy littoral rock)			LR.FLR (Features of littoral rock)
Biotope complex	LR.HLR. MusB (Mussel and/or barnacle communities)		LR.HLR.FR (Robust fucoid and/or red seaweed communities)	LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock).		LR.FLR.Rkp (Rockpools)
Biotope	LR.HLR.MusB.Cht (Chthamalus sp on exposed upper eulittoral rock)	LR.HLR.MusB.Sem (Semibalanus balanoides on exposed to moderately exposed or vertical sheltered eulittoral rock)		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)

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

A 'By the wind sailor' (Velella velella)  washed up high onto the shore. This is a pelagic hydrozoa that is often washed up onto shores during the winter months.

Lichens have a patchy distribution, covering the larger and more stable boulders and bedrock of the supralittoral and littoral fringe rock. Habitat classification: LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock) EUNIS: B3.11.

Many boulders are too mobile to facilitate lichen growth, in such circumstances lichen growth is restricted to areas surrounding 'protected' crevices.

The boulders of the littoral fringe support a community of  rough and small periwinkles with seasonal growths of green ephemeral seaweeds. Towards the lower extend of the littoral fringe rock, sparse barnacles are found. On the boulders where the V. maura is absent the littoral fringe is identified by the presence of other organisms, including rough (Littorina saxatilis) and small periwinkles (Melarhaphe neritoides) and sparse barnacles. The ineffective application of the JNCC and EUNIS habitat classification to the littoral fringe boulder habitat is rectified by the much broader 1993 phase 1 habitat classification which seems to capture these environments under the boulder habitat classification which is in turn is listed under the EUNIS website as comparable to the habitat classification supralittoral rock (lichen or splash zone).

On stable bedrock and larger boulders  V. maura is evident. Common limpets (Patella vulgata), sparse barnacles and an increased diversity of periwinkles (Littorina sp)are also present. The mobile organisms congregate within crevices, nooks and crannies or the leeward sides of rock in a bid to avoid wave exposure.

Littorinid identifications helped by Ian Smith..... 

Rough periwinkles (Littorina saxatilis agg)

Rough periwinkles (Littorina saxatilis agg)

Rough periwinkles (Littorina compressa)

Rough periwinkles (Littorina compressa)

Rough periwinkles (Littorina sp)

The bedrock of the upper eulittoral supports barnacle communities and shallow coralline rockpools. Patches of the lichen, Lichina pygmaea occur on certain rock faces, as does Verrucaria mucosa, whilst the crevices support mussels (Mytilus edulis), periwinkles and  beadlet anemones (Actina equina). Habitat classification: LR.HLR.MusB.Cht (Chthamalus sp on exposed upper eulittoral rock) EUNIS: A1.112 and LR.HLR.MusB.Sem (Semibalanus balanoides on exposed to moderately exposed or vertical sheltered eulittoral rock) EUNIS: A1.113.

Patches of Lichina pygmaea show seasonal die back.

Barnacles

Coralline rockpools occur throughout the bedrock of the eulittoral. During the winter months the ephemeral seaweeds of the pools have died back, as too has those corallinaceae crusts that were exposed to the sun. China limpets (Patella ulyssiponensis),  M. edulis and the seaweeds Corallinaceae crusts, Corallina officinalis, Chondrus crispus and ephemeral greens can be found within these pools. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools) EUNIS: A1.411.

Mid eulittoral bedrock and less stable boulders, support a more patchy distribution of barnacles, and appear 'pinker' as the granite colour can be seen. Robust fucoids cling on in this environment and between the boulders are filter feeders and robust red seaweeds and beadlet anemones (Actina equina) and among boulders in sheltered gullies are dog whelks (Nucella lapillus) and topshells. Habitat classification: LR.HLR.MusB.Sem (Semibalanus balanoides on exposed to moderately exposed or vertical sheltered eulittoral rock) EUNIS: A1.113.

A flat topshell (Littorina sp) found among the robust fucoids.

Where wave exposure and scour from pebbles and cobbles is high, faunal cover is low.

Bedrock of the lower eulittoral supports an ever increasing diversity of filter feeders, that form 'turfs' with the robust red seaweeds.Habitat classification: LR.HLR.FR (Robust fucoid and/or red seaweed communities) EUNIS: A1.12

Sponges occur beneath shaded over hangs.

Red seaweeds including, Palmaria palmata, Corallinaceae crusts and foliose reds, lace a gully of the lower eulittoral. 

Red seaweed diversity is highest on the lower eulittoral, comprising Calliblepharis sp, Fucus serratus,  Chondrus crispus, Mastrocarous stellatus, Corallinaceae crusts, Corallina officinalis,  Geldium sp and others.

The coralline rockpools of the lower eulittoral support higher densities and diversity of red seaweeds and anemones. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools) EUNIS: A1.411.

In those rockpools filled with coarser sediment the diversity is less.