Rock Pools at Ferriters Cove

There are some unusual mini-habitats in the shallow pools that occupy the cracks and crevices between bedding planes of the Silurian strata at Ferriters Cove. Only a few seashore creatures are seen grazing within them. A few common periwinkles (Littorina littorea) and limpets (Patella sp.) are the most frequent inhabitants. The pools have a few isolated branching seaweeds – some miniscule fine branching greens but mostly tiny clumps of Coral Weed (Corallina officinalis).

However, the rock surfaces beneath the water are also covered with a continuous coating, or small individual patches, of a variety of coloured algae such as the chalky red encrusting seaweeds like Pink Paint Weeds (Corallinaceae crusts); dark red non-calcareous encrusting seaweeds (Hildenbrandia rubra and Peyssonnelia sp. are examples in this group but not necessarily present at this location); encrusting brown seaweeds (Aglaozonia sp. and Ralfsia verrucosa would be examples of the type algae in this group); and the commonly occurring bright green algal films. Less obvious to the naked eye but probably also present in this kind of habitat would be the biofilms created by microscopic cyanobacteria, fungi, and lichens.

It is difficult to identify the species or even genera without taking samples to section and examine under the microscope. A complication with the identification or classification of these encrusting seaweeds, particularly the dark reds, is that the crustal form may represent a true species in its own right, or it may simply be only one life stage (tetrasporophyte phase) in the life cycle of a more familiar-looking foliose (branching) seaweed, or even an extensive attachment disc for a foliose alga.