3 results for 'SS.SMp.KSwSS.SlatR.CbPb'
SS.SMp.KSwSS.SlatR.CbPb Red seaweeds and kelps on tide-swept mobile infralittoral cobbles and pebbles
Shallow mixed substrata of cobbles and pebbles swept by moderately strong tidal streams in exposed areas, and characterised by dense stands of red seaweeds. Tide-swept infralittoral cobbles and pebbles which may be highly mobile, create an environment that is difficult for many algae to survive in. Foliose and filamentous seaweeds with an encrusting phase in their life history, or those that are able to withstand rolling of the substratum and scouring, can form dense turfs of seaweed in the more settled summer months. Characteristic red seaweeds include Halarachnion ligulatum which is able to survive attached to the pebbles and cobbles. Ephemeral algae grow rapidly in periods of relative stability. Other characteristic red seaweeds include Plocamium cartilagineum, Hypoglossum hypoglossoides, Bonnemaisonia asparagoides and Vertebrata byssoides. Coralline encrusting algae cover many of the cobbles and pebbles; some areas of cobbles may be quite barren, dominated only by encrusting coralline algae and brittlestars. Of the brown seaweeds scattered Laminaria spp. and Desmarestia spp. may be present on more stable large boulders or bedrock outcrops. Chorda filum and Halidrys siliquosa may be present in low abundance but where these seaweeds occur in greater abundance (typically >Frequent) refer to IR.HIR.KSed.SlatChoR and IR.HIR.KSed.XKHal, respectively. Although the faunal component of this biotope is usually relatively sparse it can include a wide variety of species. Turfs of hydroids (Nemertesia spp., Aglaophenia tubulifera) and bryozoans (Crisia spp. and Bugula spp.) are the major components but sponges and anemones may also occur. Brittlestars, sea-urchins, hydroids and solitary ascidians are more prominent in the Scottish examples of this biotope, which tend to occur in deeper water, due in part to clearer waters.
SS.SMp.KSwSS.SlatR.Gv Saccharina latissima and robust red algae on infralittoral gravel and pebbles
Shallow kelp community found on gravel and gravelly sand in slightly less exposed areas than SS.SMp.KSwSS.SlatR.CbPb but in moderately strong tidal currents, and characterised by occasional Saccharina latissima with an undergrowth of robust red seaweeds. Characteristic red seaweeds, as with SS.SMp.KSwSS.SlatR.CbPb, include Plocamium cartilagineum, Halarachnion ligulatum and Vertebrata byssoides. However, the greater stability of this biotope allows a slightly more diverse range of red seaweeds to become established including Polyides rotunda, Rhodophyllis divaricata, Delesseria sanguinea and Nitophyllum punctatum. Coralline encrusting algae may be found covering the larger pebbles. Laminaria hyperborea may also be present within this biotope at low densities. Other brown algal species present include Desmarestia spp., Dictyota dichotoma and Chorda filum, all at low abundance. The ubiquitous green seaweed Ulva sp. may be found attached to larger pebbles.
SS.SMp.KSwSS.SlatR Saccharina latissima and red seaweeds on infralittoral sediments
On infralittoral mixed muddy substrata communities characterised by the kelp Saccharina latissima and mixed filamentous and foliose red algae can be found. This biotope contains a number of sub-biotopes distinguished by the degree of either wave or tidal exposure. In moderately strong tidal streams in exposed areas Laminaria is sparse and dense stands of red seaweeds are found attached to the boulders and cobbles that make up a large proportion of the sediment (SS.SMp.KSwSS.SlatR.CbPb). As the degree of wave and/or tidal exposure decreases there is a change in community structure, with the density of Laminaria and the diversity of red algal species increasing (SS.SMp.KSwSS.SlatR.Gv). As the environment becomes more stable a few brown algal species are able to inhabit this environment and a rich infauna develops (SS.SMp.KSwSS.SlatR.Sa). In the most sheltered examples of this biotope a diverse muddy sediment infauna can be found and the 'Trailliella' phase of Bonnemaisonia hamifera may develop (SS.SMp.KSwSS.SlatR.Mu).