Laminaria saccharina and/or Saccorhiza polyschides on exposed infralittoral rock
Image Paul Brazier - Saccharina latissima and/or Saccorhiza polyschides on exposed infralittoral rock. Image width ca XX m.
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Ecological and functional relationships
The species in this biotope are either short lived opportunist species or are mobile species that migrate into the area. Kelps provide a habitat for a variety of encrusting bryozoans and the holdfasts may be colonized by mobile species including polychaete worms, crustaceans and prosobranch molluscs. The limpet Helcion pellucidum may feed on the kelps especially Saccorhiza polyschides. Grazing species such as the sea urchin Echinus esculentus are likely to keep rocks clear of a dense growth of erect algae. Kelps may provide local shelter for small fish such as the two-spotted goby Gobiusculus flavescens.
Seasonal and longer term change
This biotope will be highly changeable in relation especially to the onset of winter storms when most of the algae can be expected to be removed by scour. However, some parts of algae are likely to remain and, in less stormy winters, the biotope might remain largely intact and begin to show growth of longer lived kelps especially Laminaria hyperborea.
Habitat structure and complexity
Complexity in the biotope is brought about particularly by the structures in the kelp forest where fronds stipes and holdfasts provide different habitats for occupancy by associated species. For instance, Saccorhiza polyschides
are known to shelter large animals such as large polychaetes, squat lobsters and fish inside the bulbous holdfast, while amphipods, brittle stars and polychaetes occur in the space between the base of the bulb and the rock surface to which it is attached (McKenzie & Moore, 1981). Similar species are associated with Saccharina latissima
although holdfast faunas are of smaller species that live in the interstices between haptera. Fronds of kelps are grazed by urchins such as Echinus esculentus
and Paracentrotus lividus
, and the blue-rayed limpet Helcion pellucidum
. There will also be significant shelter afforded by foliose algae.
Rocks may have fissures and crevices providing further refuges for animal species.
This biotope would appear to be productive of organic matter from seaweeds especially (primary production).
The dominant and characteristic species are recruited from planktonic larvae and spores. Other species such as fish, sea urchins and crustaceans are mainly migratory.
Time for community to reach maturity
Providing that sources of larvae, spores and mobile animals are nearby, the biotope would develop rapidly on new substrata so that, in appearance based on visually dominant species, it would be likely to be established in less than a year.
This review can be cited as follows:
Laminaria saccharina and/or Saccorhiza polyschides on exposed infralittoral rock.
Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line].
Plymouth: Marine Biological Association of the United Kingdom.
Available from: <http://www.marlin.ac.uk/habitatecology.php?habitatid=237&code=1997>