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 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.

Rockpooling Destination: Treen Cornwall April 2015

The shore comprises shelving bedrock with gullies and rockpools. Lichens communities dominate large areas of the shore, eventually giving way to barnacle and mussel/fucoid communities. Rockpools occur throughout the shore, varying in species composition depending on their level of exposure to air and wave.

Below are images of the habitats and organisms you  may encounter whilst rockpooling on this shore:

The shore comprises shelving bedrock with gullies and rockpools. Lichens communities dominate large areas of the shore before they give way to barnacle and mussel/fucoid communities. Rockpools occur throughout the shore, varying in species composition depending on their level of exposure to air and wave. Habitat classification: LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock) EUNIS B3.111, LR.FLR.Lic.Ver (Verrucaria Maura on littoral fringe rock) EUNIS: B3.113, LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools)  EUNIS: A1.4111, LR.HLR. MusB (Mussel and/or barnacle communities) EUNIS: A1.11.

Coralline rockpools and lower barnacle/fucoid shore communities:

On the mid to lower shore the coralline rockpools increase in species diversity, including increased numbers of red seaweeds and gastropods. Habitat classification: LR.FLR.Rkp.Cor.Cor (Coralline crusts and Corallina officinalis in shallow eulittoral rockpools) EUNIS: A1.4111.

The coralline rockpools come in a variety of shapes, sizes and depths which in turn influences the species found within.

A large coralline rockpool.

Corallina officinalis forms a turf on the edge of this deeper coralline rockpool.

The coralline rockpools support a variety of species, including Corallinaceae crusts, Mytilus edulis,  Corallina officinalis, Ulva spp and China limpets (Patella ulyssiponensis). The grazing gastropods can reduce the abundance of seaweeds within the rockpool, sometimes to such an extent that only a few non encrusting individuals remain!

Periwinkles (Littorina spp)

A blenny and beadlet anemones (Actina equina)

Corallinaceae crusts and Corallina officinalis.

 Corallina officinalis.

Corallina spp. turf

Barnacles 'peak' out from the surrounding Corallinaceae crusts that envelope them.

A china limpet (Patella ulyssiponensis)

Corallinaceae crusts and sponge.

Snakelocks anemones (Anemonia viridis)

Where seaweeds can avoid grazing pressure a range of filamentous reds occur.
Ceranium spp

Many seaweeds avoid grazing by living on the grazers' shell!

A limpet encrusted by Corallinaceae crust.

Coralline rockpools of the lower shore support a greater number of brown seaweeds, and on this shore are typically characterised by the presence of the brown forking weed (Bifurcaria bifurcata).  Habitat classification: LR.FLR.Rkp.Cor.Bif  (Bifurcaria bifurcata in shallow eulittoral rockpools) EUNIS: A1.41113

Bifurcaria bifurcata  and Corallina officinalis

Young Himanthalia elongata overgrows Bifurcaria bifurcata and could, at this stage of growth, be confused with it.

Kelps may also be present within the deeper lower shore rockpools.

Red seaweed diversity and abundance increase within these deeper lower shore rockpools.

Chondrus crispus

Robust fucoids occur within a discrete band across the bedrock, marking the boundary between the barnacle dominated communities to the barnacle and fucoid communities.

Robust Fucus spp. showing signs of winter die back.

New growth of Fucus spp.

Deep crevices run through the bedrock, these shady areas retain water and contain coralline rockpools.

As the lower shore is reached there is an increase in those species that are more vulnerable to dessication. Beadlet anemones occur at a high abundance and Coralline algae is also able to grow where water seeps down the rock from the rockpools above. Habitat classification: LR.HLR.MusB (Mussel and/or barnacle communities) EUNIS A1.11.

Dog whelk (Nucella lapilus) abundance increase.


Dog whelks (Nucella lapilus), Limpets and barnacles.

Red seaweeds are no longer confined to rockpools and occur within the damp crevices and pits of the bedrock.

Dog whelks (Nucella lapillus)

Small periwinkles (Melarhaphe neritoides) seek refuge among the barnacles

Barnacles

Eventually the low water mark is characterised by Corallinaceae crusts and red seaweeds that cover the lower shore bedrock