Thursday 10 October 2013

Rock pooling destination: Behind the harbour Cafe on Eigg, May 2013

The shore comprises a bedrock platform that drops off towards the low tide mark and contains a number of rock pools.

Lichens occur in the splash zone and extend into the upper shore with channel wrack and periwinkles. The mid to lower shore is covered by a patch work of fucoids and barnacles. Rock pools occur across the shore, with species diversity increasing as you near the low tide mark.


Habitat classifications: 

Substrate
LR (Littoral rock)
Habitat
MLR (Moderate energy littoral rock)
FLR (Features of ilttoral rock)
Biotope complex
BF (Barnacles and fucoids on moderately exposed shores)
Rkp (Rockpools)
LR.FLR.Lic (Lichens or small green algae on supralittoral rock)
Biotope
LR.LMR.BF       (Pelvetia canaliculata and barnacles on moderately exposed shores)
LR.MLR.BF.FspiB (Fucus spiralis on full salinity exposed to moderately exposed upper eulittoral rock)
LR.FLR.Rkp.G        (Green seaweeds (Entomorpha spp. and Cladophora spp.) in shallow upper shore rock pools)
LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools)
LR.FLR.Lic.Ver (Verrucaria Maura on littoral fringe rock)

Below are images of some of the organisms you may encounter whilst rock pooling in these habitats:
The rocky shore at Eigg. Habitat classifications: LR.FLR.Lic (Lichens or small green algae on supralittoral rock), LR.MLR.BF (Barnacles and fucoids on moderately exposed shores) and LR.FLR.Rkp (Rock pools).


A rock pool in the upper shore is dominated by Entomorpha spp. Entomorpha spp. characterises the biotope LR.FLR.Rkp.G (Green seaweeds (Entomorpha spp. and cladophora spp. in shallow upper shore rock pools.) that occurs within the broader biotope complex LR.FLR.Rkp (Rockpools). The black lichen Verrucaria maura covers the surrounding rocks and characterises the biotope  LR.FLR.Lic.Ver (Verrucaria Maura on littoral fringe rock) that occurs within the broader biotope complex of LR.FLR.Lic (Lichens or small green algae on supralittoral rock).

Small periwinkles (Melarhaphe neritoides) seek shelter from desiccation within a crevice on the upper shore. Habitat classification: LR.FLR.Lic.Ver (Verrucaria Maura on littoral fringe rock).

The periwinkles, Littorina saxatilis and Melarhaphe neritoides) with Channel wrack (Pelvetia canaliculata)on the upper shore. Pelvetia canaliculata characterises the biotope LR.LMR.BF (Pelvetia canaliculata and barnacles on moderately exposed shores) that occurs within the broader biotope complex of LR.MLR.BF (Barnacles and fucoids on moderately exposed shores). The band of channel wrack delimits the upper extent of the biotope complex.

Channel wrack (Pelvetia canaliculata) and spiral wrack (Fucus spiralis) on the upper shore. Habitat classification: LR.LMR.BF (Pelvetia canaliculata and barnacles on moderately exposed shores).

The periwinkles, Littorina saxatilis and Melarhaphe neritoides) seek refuge in a rock pool of the upper shore. Habitat classification: LR.FLR.Rkp (Rockpools).

Rough periwinkles (Littorina saxatilis) and Entomorpha spp. in a pool. Habitat classification: LR.FLR.Rkp (Rockpools).

A shallow rock pool edges by clumps of spiral wrack (Fucus spiralis). Fucus spiralis characterises the biotope LR.MLR.BF.FspiB (Fucus spiralis on full salinity exposed to moderately exposed upper eulittoral rock) that occurs within the broader biotope complex of LR.MLR.BF (Barnacles and fucoids on moderately exposed shores). The rock pool itself holds a few patches of coralline crust and green algae. Habitat classification: LR.FLR.Rkp (Rockpools).

Seaweed deposited by wave action fills a rockpool; as the seaweed decomposes and using the available oxygen within the pool it can, over time, become stagnant. Habitat classification: LR.FLR.Rkp (Rockpools)

Spiral wrack (Fucus spiralis) has a patchy distribution interspersed with barnacles and rock pools. Habitat classification: LR.MLR.BF.FspiB (Fucus spiralis on full salinity exposed to moderately exposed upper eulittoral rock) and LR.FLR.Rkp (Rockpools).

Coralline crust extends over the bottom of the rock pool together with clumps of green algae, while spiral wrack (Fucus spiralis) edges the rock pool. Coralline crusts characterises the biotope LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools) that occurs within the broader biotope complex LR.FLR.Rkp (Rock pools).

A coralline crust dominated pool, with coral weed (Corallina officinalis), beadlet anemones (Actinia equina),  limpets (Patella sp), Topshells (Gibbula spp.), barnacles, the red seaweeds Osmundea spp and green seaweeds. Habitat classification: LR.FLR.Rkp.Cor (Coralline crust dominated shallow eulittoral rockpools). Surrounding the pool is a mosaic of barnacles and spiral wrack (Fucus spiralis). Habitat classification: LR.MLR.BF.FspiB (Fucus spiralis on full salinity exposed to moderately exposed upper eulittoral rock).


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