Sargassum muticum on shallow slightly tide-swept infralittoral mixed substrata

English name: Sargassum muticum on shallow slightly tide-swept infralittoral mixed substrata

Quick facts

EUNIS habitat type code A3.315
Bern Convention Included in a Resolution 4 habitat type at a higher level (A3)

Description (English)

Mixed substrata from the sublittoral fringe to 5m below chart datum dominated by the brown seaweed Sargassum muticum. This invasive non-native brown seaweed can form a dense canopy on areas of mixed substrata (typically 0-10% bedrock on 90-100% sandy sediment). The substrate on which this S. muticum-dominated community is able to develop is highly variable, but particularly prevalent on broken rock and pebbles anchored in sandy sediment. The pebbles, cobbles and broken bedrock provide a substrate for alga such as the kelp Laminaria saccharina. During the spring, S. muticum has large quantities of epiphytic ectocarpales and may also support some epifauna e.g. the hydroid Obelia geniculata commonly found on kelp. The brown seaweed Chorda filum, which thrives well on these mixed substrata, is also commonly found with S. muticum during the summer months. In Strangford Lough, where this biotope occurs, the amphipod Dexamine spinosa has been recorded to dominate the epiphytic fauna (this is known to be commonly found in Zostera spp. beds). S. muticum is also found on hard, bedrock substrates within L. saccharina canopies. S. muticum plants on hard substrate area, under a dense L. saccharina canopy, are typically smaller and at a much lower density, especially where a lush, under-storey exists with red seaweeds such as Ceramium nodolosum, Gracilaria gracilis, Chylocladia verticillata, Pterosiphonia plumula and Polysiphonia elongata and the green seaweeds Cladophora sp., Ulva lactuca and Bryopsis plumosa. The anthozoan Anemonia viridis and the crab Necora puber can be present. More information is necessary to validate this description.
Situation: Where there is a greater proportion of bedrock or boulders (15-100%) L. saccharina will typically dominate the canopy. Areas with pebble cover on a hard substrate are colonised by S. muticum, but individuals quickly become peripatetic and are lost.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Anemonia viridis
Algae Bryopsis plumosa
Algae Chorda filum
Algae Chylocladia verticillata
Invertebrates Dexamine spinosa
Algae Gracilaria gracilis
Algae Laminaria saccharina
Invertebrates Necora puber
Invertebrates Obelia geniculata
Algae Polysiphonia elongata
Algae Sargassum muticum
Algae Ulva lactuca
Species scientific name English common name Species group
Anemonia viridis Invertebrates
Bryopsis plumosa Algae
Chorda filum Algae
Chylocladia verticillata Algae
Dexamine spinosa Invertebrates
Gracilaria gracilis Algae
Laminaria saccharina Algae
Necora puber Invertebrates
Obelia geniculata Invertebrates
Polysiphonia elongata Algae
Sargassum muticum Algae
Ulva lactuca Algae

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 IR.LIR.K.Sar <I>Sargassum muticum</I> on shallow slightly tide-swept infralittoral mixed substrata source
CORINE Land Cover 5.2.3. Sea and ocean n/a
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200410 A3.315 Sargassum muticum on shallow slightly tide-swept infralittoral mixed substrata same
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