Rockpooling Destination: Revisit Lands' End Penisular, April 2015 - Ephemeral seaweeds to Fucoid and Barnacle habitats

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)

 Below are images of organisms you may encounter whilst rockpooling in the upper and mid shore habitats:

One year ago these boulders were covered by sand. Now uncovered they are slowly being colonized by organisms, either from neighbouring rock or from planktonic recruitment.

Boulders and rockpools of the upper to mid shore that are influenced by the fresh water run off and sand scour are characterised by ephemeral red and green seaweeds. Habitat classification: LR.FLR.Eph (Ephermeral green or red  seaweeds (Fresh water or sand influenced) EUNIS:A2.82

The ephermeral green and/or red  seaweed biotope extends over much of the upper and mid shore coinciding with the rivers flow.

Ephemeral green algae (Ulva spp - previously Entomorpha spp)

The distribution of fauna in the mid to lower shore is influenced by wave exposure, subtidal sand scour, fresh water run off and desiccation. The result is a patchwork of biotopes that are not distributed evenly down the shore. Here fucoids and barnacles cover the boulders, whilst ephemeral green algae lace the diluted pools where the river flows to the sea.  Habitat classification: LR.MLR. BF (Barnacles and fucoids on moderately exposed shores) and LR.FLR.Eph (Ephermeral green or red seaweeds (Fresh water or sand influenced). 

Unlike the upper shore the mid shore habitats appear unchanged from October, 2014 when this photograph was taken.

The fucoid and barnacle community of the  LR.MLR. BF (Barnacles and fucoids on moderately exposed shores) habitat comprises dog whelks, beadelt anemones, barnacles and red seaweeds, among other species....

Beadlet anemone (Actinia equina)

A Chiton, so highly camouflaged it could be missed among the coralline edged rock.

Gibbula umbilicus can be found between and under the boulders, where conditions are damper.

Limpets are able to withstand greater desiccation than other shore gastropods and are found all over the boulders, usually aggregated on the lee ward side.  

New fucoid growth, on a particularly sandy boulder. As the lower shore is reached the influence of subtidal sand scour increases and this influences the organisms found.

Fucus sp and a red seaweed.