Table 1 The location features (mean period of emersion during one tide in hours; parallel and perpendicular extension to the coastline in metres) and dominating algal species of the six habitats of the abrasion platform
Vertical belt | Location features | Dominant algal species | |||
|---|---|---|---|---|---|
Zone | Mean period of emersion | Parallel extension | Perpendicular extension | ||
Enteromorpha-zone | High intertidal | ca. 6 | ca. 15–40 | ca. 50–60 | Enteromorpha spp., Ulva spp., Ulothrix/Urospora spp., Fucus serratus |
Mytilus edulis-zone | Mid intertidal | ca. 4 | ca. 35-80 | ca. 60–70 | Seasonal species (e.g. Cladophora sericea, Monostroma spp., Rhizoclonium tortuosum, Dumontia contorta), F. serratus, Fucus vesiculosus, Ralfsia verrucosa, Chondrus crispus, Mastocarpus stellatus, Phymatholithon spp. |
Fucus serratus-zone | Low intertidal | ca. 2.5 | ca. 100-210 | ca. 60–150 | Cladophora rupestris, F. serratus, C. crispus, Corallina officinalis, Phymatholithon spp. |
Channels | Shallow subtidal | Permanently submerged except for short times during extreme spring tides | – | ca. 3–5 | Ulva spp., seasonal species (e.g. Cladophora spp., Rhizoclonium tortuosum), Sargassum muticum, Laminaria digitata, F. serratus, C. officinalis, C. crispus, Phymatholithon spp. |
Laminaria-zone | Subtidal | (see channels) | From ca. 230 | – | Ulva spp., C. rupestris, L. digitata, F. serratus, C. officinalis, C. crispus, Phymatholithon spp. |