Rockpooling Destination: Land's End Penisula March 2016 (Part 2)

Continued from the previous blog:

The rocky shore in March, 2016 has changed from that observed in June, 2015 with increased sand deposition and reduced seaweed cover and rockpool abundance.

The habitats encountered are consistent with those previously recorded in September 2015 but the distribution and extent of each habitat has changed.

Habitat classification:

Substrate	LR (Littoral rock)						LS (Littoral Sediments)
Habitat	LR.HLR (High energy littoral rock)	LR.MLR (Moderate energy littoral rock)	LR.FLR (Features of littoral rock)				LS.Lsa (Littoral Sand)
Biotope complex	LR.HLR.MusB (Mussel and/or barnacle communities)	LR.MLR.BF (Barnacles and fucoids on moderately exposed shores)	LR.FLR.Rkp (Rockpools)		LR.FLR.Eph (Ephemeral green or red seaweed communities)	LR.FLR.Lic (Lichens and small green algae on suprallitoral and littoral fringe rock)
Biotope		LR.MLR.BF.Fser.R (Fucus serratus and red seaweeds on moderately exposed lower eulittoral rock)	LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools)	LR.FLR.Rkp.SwSed (Seaweeds in sediment-floored eulittoral rockpools)

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

Lichens on supralittoral and littoral fringe rock. Habitat classification LR.FLR.Lic (Lichens on supralittoral and littoral fringe rock) EUNIS: B3.11

Green algae surrounds the fresh water falls.

Ephemeral green algae cover upper shore rocks around the stack.

Small and rough periwinkles occur among these boulders.


Rough periwinkle (Littorina sp)

Increased sand deposits have formed a sandy area in the left hand side of the bay's upper shore. Habitat classification: LS.Lsa (Littoral Sand).

The distribution of organisms has changed in response to the sand deposition, with many gastropods taking to the cliff walls and extending further up the cliff than would usually be encountered.

The  rocks to the right of the bay have not experienced the same amount of sand deposition and hence support habitats similar to that observed during previous rockpooling visits. Ephemeral green and red seaweeds cover boulders of the upper to mid shore, with  barnacles throughout. The bedrock also supports ephemeral greens such as Ulva sp and Cladophora sp, especially where influenced by the fresh water runoff from the river. Lastly the patches of the lower shore support a canopy of Fucus serratus under which reds can be found. Habitat classification: LR.FLR.Eph (Ephemeral green or, red seaweeds (Fresh water or sand influenced) EUNIS: A1.45 and LR.FLR.Rkp (Rockpools) EUNIS: A1.41,LR.MLR.BF (Barnacles and fucoids on moderately exposed shores) EUNIS: A1.21 and LR.FLR.Rkp (Rockpools) EUNIS: A1.4.

Coralline rockpools on the stack appear to have been unaffected by the sand deposition on the shore and are continuing their establishment. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools) EUNIS: A1.41.

Bifucaria bifactata is becoming established within the deeper coralline rockpools.

 Scytosiphon lomentaria grows on a china limpet

Barnacles and limpets occur at variable densities across the shore where there are boulders and bedrock. Among the boulders of the lower shore are patches of green algae, Verrucaria mucosa and the occasional dog whelk (Nucella lapillus).

Fucus serratus forms a patchy canopy on the lower shore.

The abundance of F. serratus has reduced with the increased sand deposition which has scoured and buried the seaweeds.

The sand has infilled in the rockpools and covered the bedrock.

 This photograph shows the Cladophora sp that once covered the bedrock together with sandbinder (Rhodothaminiella floridula). Now these seaweeds occur in patches.

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.

Rockpooling Destination: Revisit Land's End Peninsular April 2015 - Littoral fringe, barnacle communities and coralline rockpools

Steep cliffs surround the bay, the lower craggy edges covered in lichens. The cliff bases and steeper bedrock transition between the lichen and barnacle communities with limpets, periwinkles and whelks. Boulders and bedrock of the mid and lower shore host a similar barnacle community plus a variety of seaweeds, including where sand scour is event, ephemeral seaweeds. Rockpools occur throughout the shore, and a river flows downs from the cliffs.

The bay experiences a dynamic regime, alternating between periods of erosion and deposition. The underlying substrate is boulders and bedrock, however, variable amounts of sand may be deposited on top, sourced from the sand bar situated offshore. The communities encountered reflect the alternation between these regimes.


The shore alternates between periods of deposition, sandy  and erosion, stony.

April 2015

September 2013                    January 2014
The overlaying sand has been eroded to reveal the boulders beneath.

At the time of visitation the cove was comprised of boulders and bedrock with an occasional thin veneer of sand.

Habitat classification:

Substrate	LR (Littoral rock)
Habitat	LR.HLR (High energy littoral rock)	LR.MLR (Moderate energy littoral rock)		LR.FLR (Features of ilttoral rock)
Biotope complex	LR.  HLR.MusB (Mussels and/or barnacles on high energy littoral rock)	LR.MLR.BF (Barnacles and fucoids on moderately exposed shores)		LR.FLR.Lic.(Lichens on supralittoral and littoral fringe rock).	LR.FLR.Rkp (Rockpools)		LR.FLR.Eph (Ephemeral green or red seaweed communities		LR.FLR.CvoV (Littoral caves and overhangs).
Biotope		LR.MLR.BF.Fser (Fucus serratus on   moderately exposed eulittoral rock)	LR.MLR.BF.Rho (Rhodothamniella floridula on sand scoured lower eulittoral rock)	LR.FLR.Lic.Ver (Verrucaria Maura on littoral fringe rock)	LR.FLR.Rkp.Cor (Coralline crust-dominated shallow eulittoral rockpools)	LR.FLR.Rckp.SwSed (Seaweeds in sediment- floored eulittoral rockpools).	LR.FLR.Eph (Ephermeral green or red   seaweeds (Fresh water or sand influenced)	LR.FLR.Eph.EntPor (Porphyra purpurea and Entomorpha spp. on sand scoured mid to  lower eulittoral rock)
Sub Biotope		LR.MLR.BF.Fser.R (Fucus serratus and red seaweeds on moderately exposed lower eulittoral rock)			LR.FLR.Rkp.Cor.Cor (Corallina officinalis and coralline crusts in shallow eulittoral rockpools)

Bedrock and boulders of the upper shore. A year ago theses were covered by sand, now they are slowly being colonized by fauna, many of whom appear to have moved down from the previously bare rock. Small periwinkles (Melarhaphe neritoides), Rough periwinkles (Littorina sp) and limpets occur on bedrock outcrops, whilst rockpools and boulders are becoming colonised by ephemeral greens.

The assignment of habitats to such shores can be difficult as the species present represent transitional communities that have not yet attained a stable species/ abundance relationship upon which classical biotope classification systems are based. This highlights the importance of long term monitoring of shores when conducting phase 1 habitat surveys, as the habitats found can change.

Below are images of organisms you may encounter whilst rockpooling within the littoral fringe and upper to mid shore habitats:

These photographs show the increase in ephemeral green algae cover on rocks between October 2014 and April 2015. 

Periwinkles occur on the shore and are one of the most prominent mobile fauna of the littoral fringe and upper shore.

Melarhaphe neritoides

Littorina spp and M. neritoides and sparse barnacles on the littoral fringe cliff edge.

Rough periwinkles (Littorina spp) and limpets (Patella vulgata) have begun to recolonise upper shore boulders that were previously covered by sand.

Similarly upper shore bed rock is being recolonised by limpets (Patella vulgata)

The cliff bases enable organisms to move up and down in response to the sediment regime and sand scour, as a result they support more stable barnacle communities with limpets, periwinkles, mussels and whelks. In the case of limpets the spray from the waves of this high energy shore, enable them to live far up the cliff base.Habitat classification: LR.HLR.MusB (Mussels and/or barnacles on high energy littoral rock) EUNIS: A1.11.

The base of the cliffs are hollowed by the grinding of the boulders. An indication of the high wave exposure experienced by organisms on this shore.



Barnacles and small periwinkles (Melarhaphe neritoides) cover the bases of the cliffs.

The cliff bases hold a number of small coralline rockpools that support corallinaceae crusts, limpets and red seaweeds. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust-dominated shallow eulittoral rockpools) EUNIS: A1.411

A coralline rockpool with red seaweeds and limpets.

The distribution of fauna in the upper and mid shore is influenced by wave exposure, subtidal sand scour, fresh water runoff and desiccation.  Where the upper shore is not influenced by fresh water run off, barnacle communities similar to that of the cliff bases cover the boulders. Habitat classification: LR.HLR.MusB (Mussels and/or barnacles on high energy littoral rock) EUNIS: A1.11. 

Barnacles

Barnacles

A limpet (Patella spp)

A limpet (Patella spp)

Barnacles and Littorina compressa var. nigrolineata.

Dog whelks (Nucella lapillus), Limpets (Patella spp) and barnacles.

Barnacles and Patella depressa

Verrucaria mucosa

Some boulders are smooth and uncolonised by fauna.