Ahnfeltia plicata

Researched By	Will Rayment	Data Supplied By	MarLIN
Refereed by	Dr Fabio Rindi
Taxonomy
Scientific name	Ahnfeltia plicata	Common name	A red seaweed
MCS Code	ZM186	Recent Synonyms	None
Phylum	Rhodophycota	Subphylum
Superclass		Class	Rhodophyceae
Subclass	Florideophycidae	Order	Ahnfeltiales
Suborder		Family	Ahnfeltiaceae
Genus	Ahnfeltia	Species	plicata
Subspecies
Additional Information
Taxonomy References	Fish & Fish, 1996, Dickinson, 1963, Dixon & Irvine, 1977, Maggs & Pueschel, 1989, Howson & Picton, 1997
General Biology
Growth form	Foliose, Turf, Crustose soft	Feeding method	Photoautotroph
Mobility/Movement	Permanent attachment	Environmental position	Epilithic
Typical food types	Not relevant	Habit	Attached
Bioturbator	Not relevant	Flexibility	High (>45 degrees)
Fragility	Intermediate	Size	Medium(11-20 cm)
Height		Growth Rate	See additional information
Adult dispersal potential	None	Dependency	Independent
Sociability	Solitary
Toxic/Poisonous?	No
Additional Information	Growth rate Maggs & Pueschel (1989) recorded observations on growth of Ahnfeltia plicata from Nova Scotia. 4 months after germination of carpospores, tetrasporophyte crusts had grown up to 2.6 mm in diameter. 2 months after germination of tetraspores, the basal holdfast had reached 1.1 mm in diameter, with numerous hair like fronds emerging. After 14 months the axes had grown up to 50 mm in length. In a continuous spray culture with water at 8-11°C and light intensities of 40-60 µE/m²/s, mean apical growth of Ahnfeltia plicata was 17.2 µm/day over 19 days (Indergaard et al., 1986). Permanently immersed plants under the same conditions grew at approximately 7 µm/day. Conversely, percentage biomass increase was greater under the permanent immersion regime; 0.57% increase in mass/day vs. 0.20% for the plants in spray culture (Indergaard et al., 1986).
Biology References	Fish & Fish, 1996, Dickinson, 1963, Dixon & Irvine, 1977, Maggs & Pueschel, 1989, Indergaard et al., 1986, Bird et al., 1991
Distribution and Habitat
Distribution in Britain & Ireland	Occurs on all coasts of Britain and Ireland. There is a paucity of records from south east England, reflecting a lack of suitable substrata.
Global distribution	Occurs in Europe from northern Russia to southern Portugal and in the Baltic Sea. Occurs in the Americas from arctic Canada to Mexico and is widely distributed in the Indian and Pacific Oceans.
Biogeographic range	Not researched	Depth range	lower shore to 22 m
Migratory	Non-migratory / Resident
Distribution Additional Information	Lüning (1990) suggested that Ahnfeltia plicata typically occurs as an understory algae beneath Laminaria sp. at depths of 1.5 to 4 m.
Substratum preferences	Bedrock, Cobbles, Pebbles, Coarse clean sand	Physiographic preferences	Open coast, Strait / sound, Enclosed coast / Embayment
Biological zone	Lower Eulittoral, Upper Infralittoral, Sublittoral Fringe, Lower Infralittoral	Wave exposure	Exposed, Moderately Exposed, Sheltered
Tidal stream strength/Water flow	Moderately Strong (1-3 kn), Weak (<1 kn)	Salinity	Full (30-40 psu), Variable (18-40 psu), Reduced (18-30 psu)
Habitat Additional Information
Distribution References	Fish & Fish, 1996, Dickinson, 1963, Dixon & Irvine, 1977, Maggs & Pueschel, 1989, Lüning, 1990, JNCC, 1999, Picton & Costello, 1998, Lewis, 1964, Connor et al., 1997(a), Hardy & Guiry, 2003
Reproduction/Life History
Reproductive type	Vegetative, Self-fertilization, Permanent hermaphrodite, See additional information	Developmental mechanism	Spores (sexual / asexual)
Reproductive Season	Insufficient information	Reproductive Location
Reproductive frequency	Annual protracted	Regeneration potential	No
Life span	6-10 years	Age at reproductive maturity	1-2 years
Generation time	Insufficient information	Fecundity	No information found
Egg/propagule size		Fertilization type
Larvae/Juveniles Larval/Juvenile dispersal potential Insufficient information Larval settlement period Duration of larval stage Insufficient information
Additional Information	Life span No information was found concerning the longevity of Ahnfeltia plicata. However, it is a slow maturing perennial (Dickinson, 1963) and the thallus survives several years without considerable losses (Lüning, 1990). It likely to have a life span of 5-10 years, similar to other red seaweeds, such as Furcellaria lumbricalis. Age at maturity No definitive information was found concerning age at maturity. However, Maggs & Pueschel (1989) made observations of Ahnfeltia plicata from Nova Scotia. Tetrasporophyte crusts matured and released tetraspores after 15 months. Gametangial plants had produced abundant monosporangia after 14 months but no other reproductive structures were formed during this time. Reproductive type Ahnfeltia plicata has a heteromorphic life history (Maggs & Pueschel, 1989). Carpospores formed on the female thallus as a result of sexual reproduction give rise to the tetrasporophyte encrusting form. In turn, the tetraspores formed on the tetrasporophyte phase give rise to the erect, gametophyte plants. However, male gametophytes also give rise to monosporangia, producing monospores which also develop into gametophytes. Maggs & Pueschel (1989) suggest that the recycling of erect male gametophytes may be important in habitats which are unsuitable for the encrusting phase. Timing of reproduction Maggs & Pueschel (1989) recorded observations of reproduction by Ahnfeltia plicata in Nova Scotia. Spermatangia were present on male gametophytes between July and January. Carpogonia were present on female gametophytes between July and November, carposporophytes began development between September and November, and were mature between October and July. Monosporangia, which were only found on male plants in the intertidal, were present from November to January.
Reproduction References	Dickinson, 1963, Dixon & Irvine, 1977, Maggs & Pueschel, 1989, Lüning, 1990