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IR.MIR.KT.LsacT
Laminaria saccharina with foliose red seaweeds and ascidians on sheltered tide-swept infralittoral rock

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Habitat (physical) description

Distribution

 Salinity: Full (30-35 ppt), Variable (18-35 ppt) 
 Wave exposure: Sheltered, Very sheltered, Extremely sheltered 
 Tidal streams: Strong (3-6 kn), Moderately strong (1-3 kn) 
 Substratum: Boulders, bedrock and gravel 
 Zone: Infralittoral 
 Depth Band: 0-5 m 
 Other Features:  

Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.

Previous code

This biotope occurred in previous versions of the classification as:
Lsac.T (in part) - Version: 97.06

Distribution of habitat IR.MIR.KT.LsacT  Laminaria saccharina with foliose red seaweeds and ascidians on sheltered tide-swept infralittoral rock
Distribution of habitat IR.MIR.KT.LsacT Laminaria saccharina with foliose red seaweeds and ascidians on sheltered tide-swept infralittoral rock, based on records on the UK Marine Recorder database and EUSeaMap. Red dots represent records on which the biotope is based. Blue dots show other certain records, black dots show records tentatively assigned to this biotope. Yellow areas show level 2 and 3 sublittoral and deep-sea habitats prediced by EUSeaMap within UK waters.

Biotope description

Sheltered, tide-swept rock in south-western Britain tends to be restricted to estuarine conditions, where variable salinity and increased turbidity have a significant effect on the biota. Due to the turbidity of the water, the infralittoral zone is restricted to very shallow depths. Unlike the tide-swept channels in sealochs, which support a mixed kelp canopy, the rock in these estuaries is characterised by Laminaria saccharina alone, occurring in relatively low abundance (Frequent). The brown alga Desmarestia ligulata can occur in this biotope, though never dense, along with the non-native brown seaweed Sargassum muticum. Beneath the sparse kelp, cobbles and boulders, often surrounded by sediment, are encrusted by fauna and often a dense turf of red seaweed. The foliose red seaweeds associated with this biotope include Callophyllis laciniata, Nitophyllum punctatum, Kallymenia reniformis, Gracilaria gracilis, Gymnogongrus crenulatus, Hypoglossum hypoglossoides, Rhodophyllis divaricata, Chylocladia verticillata, Cryptopleura ramosa and Erythroglossum laciniatum as well as the filamentous Ceramium nodulosum and Pterothamnion plumula. Green seaweeds Ulva lactuca, Bryopsis plumosa and Cladophora spp. may be locally abundant. The dominating faunal species vary from site to site but include sponges such as Halichondria panicea, Esperiopsis fucorum, Dysidea fragilis and Hymeniacidon perleve as well as ascidians, particularly Dendrodoa grossularia and Morchellium argus, which can cover the rocks. Also present is the anthozoan Anemonia viridis, the barnacle Balanus crenatus and the tube-building polychaete Pomatoceros triqueter. The hydroid Plumularia setacea can cover rocks and seaweed fronds Of the range of solitary ascidians found in the north-west, only Ascidiella aspersa tends also to be present in these south-western inlets. There is also a general absence of echinoderms. Where there is vertical rock present, it tends to support more fauna, including barnacles Balanus crenatus, the ascidians Clavelina lepadiformis and Botryllus schlosseri and sometines the featherstar Antedon bifida. Where soft rock allows, such as the limestone in Plymouth Sound, rock-boring organisms such as Polydora sp. may be locally abundant. Sheltered, tide-swept rock is generally restricted to the narrows or tidal rapids of marine inlets. The clear tide-swept waters of Scottish sealochs are significantly different to the marine inlets of south-west Britain. This biotope deals with the latter.

Situation

This biotope generally occurs on rocky outcrops interspersed by sediment areas. Where the rock extends into deeper water, beyond the limit of kelp, sponges and ascidians tend to dominate these sheltered, tide-swept circalittoral sites (CuSpH); also Alcyonium digitatum with sponges and Nemertesia antennina (ByErSp).

Temporal variation

Unknown.

Similar biotopes

Not applicable or unknown.

Characterising Species

Taxa Frequency Typical Abundance % Contribution to similarity
Halichondria panicea O 3
Hymeniacidon perleve F 3
Dysidea fragilis O 1
Plumularia setacea O 2
Anemonia viridis O 1
Pomatoceros triqueter O 2
Balanus crenatus O 2
Morchellium argus F 1
Dendrodoa grossularia A 4
Rhodophyllis divaricata O 3
Callophyllis laciniata O 2
Kallymenia reniformis O 2
Gracilaria gracilis O 1
Chylocladia verticillata R 1
Ceramium nodulosum F 4
Pterothamnion plumula O 1
Cryptopleura ramosa F 3
Hypoglossum hypoglossoides O 3
Nitophyllum punctatum O 3
Desmarestia ligulata R 1
Laminaria saccharina F 23
Sargassum muticum O 2
Sargassum muticum O 2
Ulva lactuca F 5
Bryopsis plumosa O 1

Example photographs of biotope

No characteristic photos currently available. If you are able to provide a photograph of this biotope please contact .


Version 15.03 of the classification adds a deep-sea section to version 04.05; therefore superseding version 04.05, 97.06 and 03.02.

This online classification should be cited as:

JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed]. Available from: jncc.defra.gov.uk/MarineHabitatClassification

Information from the shallower section (up to sublittoral sediment, taken from Version 04.05) be cited as the report accompanying Version 04.05, as follows:

CONNOR, D.W., J.H. ALLEN, N.GOLDING, K.L.HOWELL, L.M. LIEBERKNECHT, K.O. NORTHEN AND J.B. REKER (2004) The Marine Habitat Classification for Britain and Ireland Version 04.05. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISBN 1 861 07561 8


Information from the deep-sea section (added in March 2015) should be cited as the report accompanying the deep-sea section, as follows:

PARRY, M.E.V., K.L. HOWELL, B.E. NARAYANASWAMY, B.J. BETT, D.O.B. JONES, D.J. HUGHES, N. PIECHAUD, T.D. NICKELL, H. ELLWOOD, N. ASKEW, C. JENKINS and E. MANCA (2015) A Deep-sea Section for the Marine Habitat Classification of Britain and Ireland. JNCC report 530. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISSN 0963 8901