Sunday 15 March 2015

Rockpooling destination: St. Loy, Cornwall, October 2014 - Lower shore

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

 
Fauna are relatively sparse among the boulder field of the spralittoral to upper shore, increasing within the rockpools, crevices and gullies of the mid and lower shore bedrock.


As the lower shore is reached robust wracks and red seaweeds increases in abundance.




Habitat classification (Lower shore):

Substrate
LR (Littoral rock)
Habitat
LR.HLR (High energy littoral rock)
Biotope complex
LR.HLR. MusB (Mussel and/or barnacle communities)
LR.HLR.FR (Robust fucoid and/or red seaweed communities)

Below are images of some of organisms you may encounter whilst rock pooling in these habitats:



On the lower shore wave tolerant red seaweeds form turfs with the wrack, Himanthalia elongata on the boulder below the barnacle communities . Habitat classification: LR.HLR.FR (Robust fucoid and/or red seaweed communities) EUNIS A1.12 and LR.HLR. MusB (Mussel and/or barnacle communities) EUNIS A1.11.


 On the exposed shore, Coral weed (Corallina officinalis) forms a turf  with the red seaweeds Osmundea sp, Lomentaria articulata and Mastrocarpus stellatus and occasional  bootlace weed (Himanthalia elongata).

Snakelocks anemone (Anemonia viridis) and Lomentaria articulata among coralline crusts.




Snakelocks anemones (Anemonia viridis) and the red seaweeds Osmundea sp, Corallina officinalis and coralline crusts. 

Mastrocarpus stellatusOsmundea Sp, Corallina officinalis,  Lomentaria articulata, young 'buttons' of  Himanthalia elongata and Coralline crusts.


Codium Sp.,  Corallina officinalis,  young 'buttons' of  Himanthalia elongata and Coralline crusts.


Some boulders as well as bedrock are covered in turfs of seaweed.



A variety of red and green seaweeeds cover the boulder.

A mix of reds including, Lomentaria articulata and Ceranium sp.

Blue raid limpets (Patella pellucida) on the lower shore.

Corallina officinalis

Many of the red seaweeds including, Gelidiales, grow as dense clusters and turfs.


A Gelidiale and Osmundea sp


A red seaweed


A plumose red and Mastrocarpus stellatus

Creep horn (Chondracanthus acicularis)

Osmundea sp forms a turf


A limpet (Patella sp) tackles a turf of Osmudea sp.


Seaweeds cover larger limpets of the lower shore.

 Gelidiale covers a limpet of the lower shore.


Flat top shell (Gibbula umbilicalis)



An encrusting soft red algae occurs as occasional patches covering rock and barnacles of the lower shore.

A plumose red seaweed and breadcrumb sponge (Halichondria panicea ).
Coralline crust and  a band of dulse (Palmaria palmata) on the lower shore.



Palmaria palmata


Palmaria palmata

An overhang provides shade, enabling subtidal species such as,  Fried egg anemones (Actinothoe sphyrodeta) to occur within the rockpool and enables Coralline crusts, Serpulid polychaetes  and breadcrumb sponge (Halichondria panicea)to extend up the shaded boulder sides; Grey topshells (Gibbula cineraria) also occur.





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