Thursday, 30 July 2015

Rockpooling Destination: Ardnamurchan peninsula, Scotland, May 2015

At the South-west tip of the Ardnamurchan peninsula, the waves throw up a variety of sea born creatures onto the sandy beaches....

Empty sea shells of a similar density are washed up to form strand lines.
In this instance the strand line is comprised of hundreds of limpet shells.
Many moon jellyfish (Aurelia aurita) have also been washed up onto the shore.
Aurelia aurita is recognised by the four pinkish circular gonads within its domed body. This species can form large blooms during this time of year, with many accidentally becoming washed up onto the shore.

Goose barnacles attached to drift wood.

Wednesday, 29 July 2015

Rockpooling destination: Pendeen, Cornwall April 2015

The shore comprises a sandy bay flanked by outcropping bedrock and cliffs.
The exposed shore is characterised by an extended lichen zone that reaches up the cliffs to form distinct bands of yellow and grey lichens and below the black, tar lichen. Periwinkles occur across the shore and barnacle communities dominate scour free rocks of the mid and lower shore, whilst sand scoured rocks are barren or, support organisms within the rock crevices.

Habitat classification:

LR (Littoral rock)
LS (Littoral substrate)
LR.HLR (High energy littoral rock)
FLR (Features of littoral rock)
LS.LSa (Littoral sand)
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 rock)


LR.FLR.Lic.Ver (Verrucaria maura on littoral fringe rock)
LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock)

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

The shore comprises sand flanked by bedrock outcrops and cliff. Habitat classification: LS.LSa (Littoral sand) EUNIS A2.2 and LR.HLR (High energy littoral rock) EUNIS A1.1.

High wave exposure leads to an extended splash zone enabling lichens to colonise further up the cliffs. Two distinct bands of differing lichen communities can be seen. At the highest position on the supralittoral are yellow and grey lichens, whilst on the littoral fringe below black tar lichen (Verrucaria maura) covers the bedrock. Habitat classification: LR.FLR.Lic.YG (Yellow and grey lichens on supralittoral rock) EUNIS: B3111 and LR.FLR.Lic.Ver (Verrucaria maura on littoral fringe rock) EUNIS: B3.113.
Rough periwinkles (Littorina spp) are the dominant motile species of the Verrucaria maura biotope.

Littorina spp

Littorina spp
Littorina spp
A turf forming Rhodophyta

Sand scour tolerant ephemeral green and red seaweeds occur sporadically at the rock bases.

Small periwinkle (Melarhaphe neritoides)

Rough periwinkles (Littorina spp) and Small periwinkles (Melarhaphe neritoides)

Patella vulgata

Patella vulgata huddle in the leeward corner of the rock.

Barnacles occur at low abundance on the upper shore.

Barnacles and Small periwinkles (Melarhaphe neritoides).

Barnacle abundance increases on the mid and lower shore. Note that on these sand surrounded boulders, sand scour prevents further downward colonisation of barnacles. Habitat classification: LR.HLR. MusB (Mussel and/or barnacle communities) EUNIS A1.11.

Barnacles of the mid shore.

Common blue mussels (Mytilus edulis) occur within rock crevices.

The rough periwinkle, Littorina compressa var. nigrolineata occurs amongst the barnacles of the mid and lower shore.
Barnacles and M. neritoides
Else where sand scour is too prolific to enable sessile organism to grow.
In such conditions, organisms are restricted to the crevices.

M. edulis and robust fucoids grow within boulder crevices.

Barnacles, P. vulgata and M. edulis.

M. edulis

Serrated wrack (Fucus serratus) and red seaweeds grow from crevices of the lower shore boulders. Habitat classification: LR.HLR.FR (Robust fucoid and/or red seaweed communities) EUNIS: A1.12.

F. serratus

Below the F. serratus understory are a variety of robust red seaweeds.

Mastrocarpus stellatus and F. serratus
A boulder of the lower shore has become covered by sand, to reveal just the tops of the F. serratus.

Monday, 13 July 2015

Rockpooling destination: Revisit Land's End peninsular: Scour tolerant and robust fucoid/red seaweed 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:

LR (Littoral rock)

LR.HLR (High energy littoral rock)
LR.MLR (Moderate energy littoral rock)
LR.FLR (Features of ilttoral rock)
Biotope complex

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).

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 among the lower shore habitats:

The influences of subtidal sand scour increases on the lower shore, influencing the species found. Sand scour tolerant  seaweeds flourish, including the red seaweed, sand binder (Rhodothamniella floridula) and the ephemeral green Cladophora spp.

Sand binder (Rhodothamniella floridula) can attain high abundance on the shore. Habitat classification: LR.MLR.BF.Rho (Rhodothamniella floridula on sand scoured lower eulittoral rock)
Among the sandbinder covered rock are rockpools filled with sand . These sediment filled rockpools support a variety of  red and ephemeral green seaweeds  including, Corallina officinalis, Ahnfeltia plicata and Lomentaria articulata.  LR.FLR.Rkp.SwSed (Seaweeds in sediment-floored eulittoral rockpools) EUNIS:A1.413.

Rhodophtya within a sand filled rockpool of the lower shore.

Rhodophtya within a sand filled rockpool of the lower shore.

Rhodophtya (Polyides rotundus) within a sand filled rockpool of the lower shore.

Ulva spp
A sea hare (Aplysiomorphaand anemone within a sand filled rockpool of the lower shore.

The green seaweed, Bryopsis spp

A juvenile crab

Anemonia viridis

The ephemeral green seaweed, Cladophora rupestris.

Seaweed abundance within the sediment filled rockpools, especially that of ephemeral greens is not as extensive as observed in October, 2014. (See blog post )

Where sand scour is reduced  serrated wrack and red seaweeds increase in abundance to form patches among the sand binder. Habitat classification: LR.MLR.BF.Fser.R (Fucus serratus and red seaweeds on moderately exposed lower eulittoral rock) and LR.MLR.BF.Rho (Rhodothamniella floridula on sand scoured lower eulittoral rock.
 The seaweeds of  LR.MLR.BF.Fser.R (Fucus serratus and red seaweeds on moderately exposed lower eulittoral rock)  include Lomentaria articulata, Mastocarpus stellatus, Fucus serratus, Chondrus crispus, Rhodothamniella floridula and Osmundea Spp.

Grey topshell (Gibbula cineraria)
Eventually Fucus cover gives way to robust reds and Himanthalia elongata. Habitat classification: LR.HLR.FR (Robust fucoids and/or red seaweed communities) EUNIS: A1.12.

Corallina officinalis forms a turf on the bedrock with robust reds, Himanthalia elongata and Laminaria spp.

Corallina officinalis forms a turf on the bedrock.
Mastrocarpus stellatus,  Rhodothamniella floridula, Laminaria spp and Himnathlia elongata.

Osmundea spp, Corallina spp  and Himnathlia elongata.



Bifurcaria bifurcata
Chondracanthus acicularis
A turf of robust reds, dominated by Mastrocarpus stellatus,  Laminaria spp and Himnathlia elongata.

Himnathlia elongata.

Edible crab (Cancer pagurus)

Sea caves on the shore provide shade allowing species who are more sensitive to sunlight  to extend their occurrence beyond that of the rockpools. Habitat classification: LR.FLR.CvoV (Littoral caves and overhangs) EUNIS: A1.44.
Corallinaceae crusts occur within and extend beyond the rockpools of the cave entrance due to the shade provided by the overhanging cliff.

Cladophora spp and Coralinaceae crusts live in the shaded entrance of the sea cave.

Corallinaceae crusts occur within a rockpool of the cave cliff edge.