BIOTIC

BIOTIC Species Information for Lithothamnion corallioides

Researched by

Angus Jackson

Data supplied by

MarLIN

Refereed by

Dr Christine Maggs

Taxonomy

Scientific name

Lithothamnion corallioides

Common name

Maerl

MCS Code

ZM236

Recent Synonyms

None

Phylum

Rhodophycota

Subphylum

Superclass

Class

Rhodophyceae

Subclass

Florideophycidae

Order

Corallinales

Suborder

Family

Corallinaceae

Genus

Lithothamnion

Species

corallioides

Subspecies

Additional Information

Maerl is a generic name for certain coralline algae that grow unattached on the sea bed. Only two instances of the crustose form of Lithothamnion corallioides have been recorded from the British Isles; in Dorset and Devon.

Taxonomy References

Irvine & Chamberlain, 1994, Howson & Picton, 1997, Adey & McKibbin, 1970, Birkett et al., 1998,

General Biology

Growth form

Algal gravel

Feeding method

Photoautotroph

Mobility/Movement

Not relevant
See additional information

Environmental position

Epilithic

Typical food types

Not relevant

Habit

Bed forming

Bioturbator

Not relevant

Flexibility

None (< 10 degrees)

Fragility

Intermediate

Size

Small-medium(3-10cm)

Height

Growth Rate

1-2 mm/year

Adult dispersal potential

10-100m

Dependency

Independent

Sociability

Gregarious

Toxic/Poisonous?

General Biology Additional Information

Mobility is recorded as not relevant here since maerl does not fall into the available categories. It does have a crustose permanently attached form but this has only been recorded at 2 sites in the British Isles. It is typically found as an unattached plant. Maerl has been found in densities of up to 22,000 thalli per square metre. The proportion of live to dead nodules varies considerably. As far as is known, maerl continues to grow throughout its life but fragmentation limits the size of the nodules. Individual plants may reach up to 5 cm across. Maerl beds are highly species rich with 150 macroalgal species and over five hundred faunal species (of which 120 are molluscs) recorded as living on or in maerl beds (Birkett et al., 1998(a)); see the maerl biotope £IGS.Phy.HEc£ for further information. As far as is known, the maerl does not host any commensal or parasitic species. However, a few algae are almost entirely restricted to maerl communities e.g. the red algae Gelidiella calcicola, Gelidium maggsiae and the crustose Cruoria cruoriaeformis (Birkett et al., 1998(a)).

Biology References

Irvine & Chamberlain, 1994, Adey & McKibbin, 1970, Donnan & Davies, 1996, Birkett et al., 1998, Potin et al., 1990, Grall & Glémarec, 1997, Birkett et al., 1998(a), Maggs & Guiry, 1987,

Distribution and Habitat

Distribution in Britain & Ireland

Patchily distributed along the exposed western coasts of the southern British Isles. Locations include the west and south-west of Ireland, the south-west corner of Wales and a few sites off the south coast of England.

Global distribution

West and south-west British Isles south to the Canary Isles (unconfirmed records from Mauritania and Cape Verde). Also found in the Mediterranean.

Biogeographic range

Not researched

Depth range

1-30 m

Migratory

Non-migratory / Resident

Distribution Additional Information

Occurs most frequently at depths between 1-10 m. Occasionally found at depths of up to 30 m (for example Outer Galway Bay).

Substratum preferences

Pebbles
Gravel / shingle
Maerl
Muddy gravel
Coarse clean sand
Fine clean sand
Sandy mud
Muddy sand
Mud
Mixed

Physiographic preferences

Open coast
Strait / sound
Sealoch
Ria / Voe
Estuary

Biological zone

Sublittoral Fringe
Upper Infralittoral
Lower Infralittoral

Wave exposure

Moderately Exposed
Sheltered
Very Sheltered

Tidal stream strength/Water flow

Strong (3-6 kn)
Moderately Strong (1-3 kn)

Salinity

Full (30-40 psu)

Habitat Preferences Additional Information

Distribution References

Donnan & Davies, 1996, Birkett et al., 1998, Grall & Glémarec, 1997, Birkett et al., 1998(a), Hardy & Guiry, 2003, Hardy & Guiry, 2003,

Reproduction/Life History

Reproductive type

Vegetative

Developmental mechanism

Insufficient information

Reproductive Season

Insufficient information

Reproductive Location

Insufficient information

Reproductive frequency

Insufficient information

Regeneration potential

Life span

51-100 years

Age at reproductive maturity

Insufficient information

Generation time

Not relevant

Fecundity

Insufficient information

Egg/propagule size

Insufficient information

Fertilization type

Insufficient information

Larvae/Juveniles
Larval/Juvenile dispersal potential	<10m	Larval settlement period	Insufficient information
Duration of larval stage	Not relevant

Reproduction Preferences Additional Information

Maerl beds in the Sound of Iona are recorded as containing dead nodules up to 4,000 years old. Insufficient information is available on reproductive frequency, fecundity and developmental mechanism. In Britain there is only one record of a fertile plant (found in July). Consequently virtually all propagation must be presumed to be vegetative and therefore dispersal potential is recorded as low. Plants from Brittany are mostly fertile in winter but Adey and McKibbin (1970) recorded a plant from Spain being fertile in August. Cabioch (1969) suggested Lithothamnion corallioides may have phasic reproduction with peaks every six years. This may account for observed changes in the relative proportions of live Lithothamnion corallioides and Phymatolithon calcareum nodules in maerl beds. Dominance cycles with periods of about thirty years have been recorded on some of the maerl beds of northern Brittany.

Reproduction References

Irvine & Chamberlain, 1994, Adey & McKibbin, 1970, Birkett et al., 1998, Cabioch, 1969, Birkett et al., 1998(a),