BIOLOGY, POPULATIONS AND DISTRIBUTION AREA OF THE EUROPEAN ENDEMIC SPECIES PTILOTHAMNION
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Thalassas, 2005, 21 (2): 21-30
An International Journal of Marine Sciences
BIOLOGY, POPULATIONS AND DISTRIBUTION AREA OF THE
EUROPEAN ENDEMIC SPECIES PTILOTHAMNION
SPHAERICUM (CERAMIALES, RHODOPHYTA) IN THE IBERIAN
PENINSULA.
P. DÍAZ TAPIA & I. BÁRBARA
Keywords: Ptilothamnion sphaericum, seaweeds, Rhodophyta, Iberian Peninsula, Galicia, Portugal, biogeography, vegetation,
conservation, morphology, reproduction.
ABSTRACT Ptilothamnion sphaericum occurs from middle to
A study of the distribution, biology lower intertidal in seaweeds communities
populations of the European endemic species characteristic in sandy rocky like
Ptilothamnion sphaericum along the Atlantic Rhodothamniella floridula, Ophidocladus
coasts of the Iberian Peninsula, is shown. P. simpliciusculus, Plocamium cartilagineum,
sphaericum is reported by 18 localities, from Lugo Polysiphonia nigra, Hypnea musciformis or
in the North of Galicia to Algarve in the South of Ahnfeltia plicata populations, but in some
Portugal; standing up Galicia as the European localities P. sphaericum covers the middle
region containing the bigest number of citations. intertidal rocks where it develops an extensive
The morphology and reproduction of P. band. A field study of natural turfs and cultures of
sphaericum is described, as well as its habitat. tufts in laboratory show that P. sphaericum has a
Iberian tufts of P. sphaericum -composed by rigid hight ability to bear long dark periods. Individuals
erect axes and prostrate axes with rizoids- match growing at 6:18 and 9:15 light:dark photoperiods
with the tufts described in the British Isles. exhibted symptoms of deterioration at 1-3 months
Likewise polysporangia are similar to the ones and they not survived more than 3-4 months.
described in the British Isles, however anomalous Individuals longer surviving were grown at 1:23
off-wite polysporangia located in the apex of axes light:dark photoperiod; they lived in culture until
and branches were observed in Galician material. 21 months since lower temperature, irradiance and
photoperiod were similar to its natural habitat. P.
sphaericum is a successful species that colonize
sandy rocky where sand buried the tufts of the
pidita@udc.es & barbara@udc.es
algae during several months. Survival and
Departamento de Biología Animal, Biología Vegetal y colonization potential of new sustrata for P.
Ecología, sphaericum is established where environmental
Facultad de Ciencias, Universidad de A Coruña,
Campus de A Zapateira s/n, 15071 A Coruña, España. conditions are too harsh.
21P. Diaz Tapia & I. Barbara
2005). The scarce information about the P. sphaericum
distribution is due to it lives in rocky habitats mixed
with sand, from lower intertidal to upper subtidal, and
it is composed by small filamentosus thalli that are
easilly confused with another species.
In the Iberian Peninsula, P. sphaericum has only
previously been reported in three localities nearby one
another and all of them focus in the A Coruña's
province (Bárbara et al., 2001, 2002, Díaz Tapia &
Bárbara 2004). In the current reseachers that we are
carrying about the flora and vegetation of sandy-rocky
habitats of the Atlantic Iberian Peninsula we have
found new populations of P. sphaericum, thus we
increased the scarce information of this species in
Spain. Taking into account that P. sphaericum is an
endemic species poorly known, we have done a field
study of its nature populations and cultures in
laboratory to test its capacity of living in habitats
where environmental conditions are too harsh (e.g.,
moving sand scour and bury of substratum).
MATERIAL AND METHODS
Along the Atlantic Iberian Peninsula, more than 30
localities were explored to find new populations and
Figure 1. complete the Iberian distribution area of Ptilothamnion
Distribution area of Ptilothamnion sphaericum (A) Galway, (B) sphaericum. Mainly, intertidal and upper subtidal
Clare, (C) Cork, (D) Cornwall, (E) Dorset, (F) Brest, (G) Galicia
and Portugal. Localities in the Iberian Peninsula (1) Playa de
rocky substrata near to the beaches were selected. The
las Catedrales, (2) Peinzás, (3) Playa del Lago, (4) Playa de cespitose vegetation was studied in samples from 100
Santa Comba, (5) Playa de Barrañán, (6) Puerto de Sorrizo, to 1600 cm2 where we estimated visually the percent
(7) Playa de Leira, (8) Playa de Seaia, (9) Playa de Barizo, cover for the main species (Tab. 1) and subsequently
(10) Ensenada de Barda, (11) Aguiño, (12) Ribeira, (13) Punta
Area Brava, (14) Cangas, (15) Amorosa (Araujo, et al 2005.), verified in the laboratory by stereo microscope and
(16) Leça da Palmeira, (17) Buarcos, (18) Dona Ana. microscope. The algal material was preserved in 4%
formalin seawater at 4ºC in dark until its study in
laboratory. The herbarium material is housed at the
herbarium of the Universidad de Santiago de
INTRODUCTION
Compostela (SANT).
With the aim to test the variability of nature
Ptilothamnion sphaericum (P.L. Crouan et H.M.
populations, a seasonal field study was done from
Crouan ex J. Agardh) Maggs et Hommersand is an
2002 to 2004 in three Galician localities (Barrañán,
European endemic species which is only known from
Seaia and Barizo) where P. sphaericum was more
the warm-temperate NE Atlantic subregion 1, in the
abundant. Moreover, to obtain data of thallus survival
terminology of Hoek & Breeman (1990). As it shown
that could explain the ability of natural colonizacion
in the Figure 1, P. sphaericum was only reported for
populations, some turfs of P. sphaericum were cultured
the northeast of France (J. Agardh, 1851), South of the
in Petri's dish with seawater (Fig. 4H). The culture
British Isles (Maggs & Hommersand, 1993, Hardy &
conditions were: temperature 10ºC, irradiance 15 µm
Guiry, 2003) and atlantic coasts of the Iberian
m-2 s-1 (18-watt light aquarium Grolux tube) and
Peninsula (Bárbara et al., 2001, 2002, Díaz Tapia &
photoperiod (light:dark, 9:15, 6:18 and 1:23).
Bárbara, 2004, Araújo et al., 2005, Peña & Bárbara
22Biology, Populations and Distribution Area of the European Endemic Species Ptilothamniom Sphaericum (Ceramiales, Rhodophyta) in the Iberian Peninsula.
over rocky-sandy sustrata by mean of prostrate axes
Herbarium material: and rizoids (Fig. 3F-I). Dense mass of prostrate axes
LUGO: Playa de las Catedrales, Ribadeo, (Fig. 3G, H) irregularly branched, pinkish-red in
29TPJ490242, 4-XI-2003, SANT-Algae 15130. colour, 35-90 µm wide, and composed of cells 1,5-4
Peinzás, Foz, 29TPJ396277, 19-II-2003, SANT-Algae diameters long. Erect axes and rhizoids grow in middle
15131. position of prostrate cells (Fig. 3G-H) which is a
A CORUÑA: Playa de Santa Comba, Ferrol, distinctive character to Spermothamnion repens.
29TNJ580233, 22-I-2004, 26-IV-2005, SANT-Algae Unicellular rhizoids (Fig. 3I), 30-40 µm wide, up to
15154, 15599. Playa de Barrañán, Arteixo, 750 µm long and ending up in unicellular discoid
29TNH358957, 11-IX-2002, 5-XI-2002, 5-XII-2002, holdfast up to 100 µm in diameter. Ramification of the
5-I-2003, 19-III-2003, 18-X-2003, 24-XII-2003, erect axes varies from a dense irregularly secund
SANT-Algae 15021, 15120, 15122-15127. Puerto de arrangement of branches up to 4º order (Fig. 3A) to
Sorrizo, Arteixo, 29TNH352958, 18-X-2003, SANT- axes unbranched. Axes bearing polysporangia are
Algae 14998. Playa de Leira, Carballo, plentifully branched especially towards the tips (Fig.
29TNH297954, 3-III-2002, 4-XII-2002, SANT-Algae 3A, D). Erect axes dark red, sometimes brownish,
13884, 15128. Playa de Seaia, Malpica,
29TNH143975, 27-II-2002, 22-VIII-2002, 20-II-2003, A B
11-XI-2003, 29-III-2005, SANT-Algae 13878-13880,
14632, 15121, 15132, 15133, 15550. Playa de Barizo,
Malpica, 29TNH102958, 10-XII-2000, 22-VI-2001, 3-
I-2003, 5-IV-2004, 8-IV-2005, SANT-Algae 12931,
13372, 15129, 15553, 15556. Ensenada de Barda,
Ponteceso, 29TNH059924, 21-I-2003, SANT-Algae
C D E
13903. Aguiño, Ribeira, Ría de Arousa,
29TMH993077, 20-XII-2002, SANT-Algae 15153.
Punta Corbeiro, Ribeira, parte externa Ría de Arousa,
28-IV-2004, SANT-Algae 15148.
PONTEVEDRA: Punta Area Brava, Cangas, Ría
de Aldán, 29TNG134825, 25-I-2004, SANT-Algae
15033. Rodeira, Cangas, Ría de Vigo, 29TNG205783,
17-III-2004, SANT-Algae 15152.
MIHNO: Minho, Amorosa, 29TNG147098, 20-II-
2003. F G
DOURO LITORAL: Leça de Palmeira,
29TNF240601, 26-X-2004, SANT-Algae 15551.
BEIRA LITORAL: Buarcos (al noroeste),
29TNE075485, 15-XI-2004, SANT-Algae 15552.
ALGARVE: Dona Ana, 29SNB296054, 8-V-2005,
SANT-Algae 15733.
Figure 2.
A B: Intertidal rocks of the playa de Seaia (20-II-2003 and 11-
RESULTS AND DISCUSSION XI-2003, respectively), where Ptilothamnion sphaericum occurs
in dense populations. C: Subtidal populations of P. sphaericum
Description in the playa de Barrañán (19-III-2003). D: playa de Seaia (22-
VIII-2002), mixte community of Plocamium cartilagineum and
As Bárbara et al. (2001) show, individuals of Hypoglossum hypoglossoides with P. sphaericum. E y F:
Ptilothamnion sphaericum from the Iberian Peninsula Intertidal turfs of P. sphaericum in the playa de Seaia (27-II-
match with the ones described by Maggs & 2002 over Lithophyllum incrustans and 11-XI-2003 over tubes
Hommersand (1993) for the British Isles. Thallus of polychaetes, respectively). G: Mixe tuft of Hypnea
musciformis, Pterocladiella melanoidea and P. sphaericum
forms rigid tufts (up to 2,5 cm) composed by from the playa de Barrañán (11-IX-2002).
ecorticated erect filaments (Fig. 3A, D) which settle
23P. Diaz Tapia & I. Barbara
Table. 1
Galician vegetation samples containg Ptilothamnion sphaericum. Littoral level: (MI) middle intertidal, (LI) lower intertidal, (SU)
subtidal. Wave exposure: (EX) exposed, (SE) semiexposed.
24Biology, Populations and Distribution Area of the European Endemic Species Ptilothamniom Sphaericum (Ceramiales, Rhodophyta) in the Iberian Peninsula.
25P. Diaz Tapia & I. Barbara
A 150 C
1993). Polysporangia are sessile, 1-2 per cell, are
550
laterally produced near to the apex of the main axes
and branches, in series or solitary (Fig. 3D, 4A, D).
They are spherical (up to 100 µm in diameter) and
contain 8-16 spores, 32-45 µm in diameter. Although
tipical polysporangia were usually observed growing
laterally to the axes, in Barizo (April 2004) and Seaia
(March 2005) we observed several individuals with
anomalous off-white polysporangia (30-100 µm in
70 µm diameter) located in the apex of axes and branches
B (Fig. 4B, C).
D E G Ptilothamnion sphaericum is resemblance to some
Spermothamnion species, especially with S. irregulare
(J. Agardh) Ardissone (Maggs & Hommersand 1993),
which is a common especies in sandy habitats of the
180
Atlantic coasts of Iberian Peninsula. It can be confused
90 µm B 150 40 µm C
90 F
160
H
A 1,5 350
10 months 9 months 1 month D
E F 1 mm
Figura 4.
Ptilothamnion sphaericum. A: Branches with lateral
polysporangia. B-C: Anomalous off-wite polysporangia. D:
Tipical lateral polysporangia. E: Swollen cells in the middle of
apical axes. F-G: Apical rhizoids linking cells of closer
1 cm
branches. H: Culture in Petri's dish from Seaia (left, right) and
Barrañán (centre). A, D and E: Barizo (10-XII-2000); B-C:
Seaia (29-III-2003); F-G: Barrañán (19-III-2003).
increasing from a barrel-shaped apical cell (Fig. 3B- 200
G
D), 70 µm wide and 0,7-1,5 diameters long, to
cylindrical cells 50-120 µm wide and 1-3 diameters H 160
long in the middle of the erect axes. Erect axes contain
short and long cells together due to difference growing
cell. Cells contain numerous discoidal plastids (Fig.
3C) and cell wall 5-12 µm wide. As novelty for P. 40 µm
I
sphaericum, swollen cells in the middle of apical cells
(Fig. 4E) and apical rhizoids (Fig. 4F, G) linking cells Figura 3.
Ptilothamnion sphaericum. A: Brancehd erect axes with
of closer branches were observed in nature populations polysponangia. B: Apical cell and barrel-shaped cells. C: Erect
as well as in culture. cells with numerous discoidal plastids. D: Branches bearing
Sexual structures are unkown for P. sphaericumso polysporangia. E: Tufts in lower axes of Ahnfeltia plicata. F:
Habit. G-I: Prostrate axes bearing rhizoids in middle position
the classification in Ptilothamnion or Spermothamnion and several erect axes. A-D, H: Barizo (10-XII-2000); E:
genus is based in vegetative characters and the Barrañán (19-III-2003); F-G: Area Brava (25-IV-2004); I: Barizo
polysporangia development (Maggs & Hommersand, (5-IV-2004).
26Biology, Populations and Distribution Area of the European Endemic Species Ptilothamniom Sphaericum (Ceramiales, Rhodophyta) in the Iberian Peninsula.
with P. sphaericum, especially young individuals Rhodothamniella floridula, Ophidocladus
without long erect axes and branches. Both species can simpliciusculus, Hypoglossum hypoglossoides,
be distinguished in the positions of the rizhoids and the Plocamium cartilagineum, Gracilaria gracilis,
celler diameter, since in P. sphaericum, rihizoids grow Cladostephus spongiosus, Polysiphonia nigra and
in the middle of prostrate cells (Fig. 3G-I), whereas in Hypnea musciformis. Filaments of P. sphaericum form
S. repens they grow laterally and the diameter axes of a mixture of turfs with the ones of several species, like
P. sphaericum are bigger than the S. repens ones. Hypnea musciformis and Pterocladiella melanoidea
(Fig. 2G). Often, P. sphaericum is unnoticed among
Distribution filamentous species thereby samples of turfs have to be
Ptilothamnion sphaericum was first reported to the study in the laboratory to a proper specific
Iberian Peninsula in the Playa de Barizo (Bárbara et identification. Especially, Ptilothamnion sphaericum is
al., 2001) and secondly in the Playa de Leira (Bárbara a common species in the subtidal vegetation of
et al., 2002). Subsequently, it was reported for the Ahnfeltia plicata, living over hard sustrata (Fig. 2C)
Playa de Barrañán (Díaz Tapia & Bárbara 2004) and with Jania longifurca, or epiphyte of A. plicata (Fig.
new record for Portugal by Araújo et al. (2005) in the 3E) as it was described by Agardh (1851) in the
Minho's region. In the current studies that we are doing northwest France. In general, Spermothamnion repens
about the flora and vegetation of sandy-rocky, P. is an epiphytic species of A. plicata but it occurs in
sphaericum was found in 15 new localities, so it is middle and upper axes of A. plicata whereas P.
nowadays known in 18 localities along the Iberian sphaericum occurs in lower axes and over hard
Peninsula, from Lugo in the North of Galicia to sustrata; thereby its thallus can be buried by sand for
Algarve in the South of Portugal (Fig. 1). Standing up several months.
Galicia as the European region containing the bigest The ecotonic habitats of sand and rock where P.
number of citations (14 localities) and overcoming the sphaericum occurs are very stressful for the seaweeds,
Brithis Isles, where it is reported only a few sites since they are usually scoured and buried by sand. In
(Maggs & Hommersand 1993, Hardy & Guiry 2003). contrast with the rocky platforms, removing thallus
Taking into account that the number of Iberian tissue, decreasing light and substratum, as well as
localities of P. sphaericum has increased in the last depth, duration of burial and degree of water motion
four years, it will feasible an increasing of new records are important disturbance agents modifying the
towards Cantabric sea and Mediterranean Spain. Even recruitment and settlement of spores and plant growing
in the Northern Africa since the lusitanic endemic in sandy-rocky substrata (Devinny & Volse 1978,
species Eryhroglossum lusitanicum Ardré was D'Antonio 1986, Chapman & Fletcher 2002).
likewise reported for the Atlantic coasts of Morocco However, sandy-rocky substrata have a characteristic
(see Benhissoune et al., 2003). vegetation that usually cover the substratum owing to
a selection of competitive species that can endure the
Habitat stressful condition of life, like the opportunists, stress-
In the Atlantic Iberian Peninsula, Ptilothamnion tolerant and biotically-competent species commented
sphaericum is usually collected in sandy-rocky by Littler et al. (1983). Filaments -retraining sand and
habitats (Fig. 2A-D) from middle and lower intertidal forming bushy cousions made of mixture of soft
to upper subtidal of exposed and semiexposed substratum and algae thallus- are the predominant
localities and, recently, it was found in subtidal maërl vegetation covering the sand-rocky plataforms of the
beds of Galicia (Peña & Bárbara 2005). These soft northwest Iberian Peninsula similarly that Hommeril
substrata of the Iberian habitats are similar to the ones & Rioult (1965), D´Antonio (1986), Stewart (1983)
mentioned by Maggs & Hommersand (1993) for the and Airoldi et al. (1995) observed in other countries.
British Isles and not present distinguished diferences in Like Airoldi (1998) comment the monopolization of
latitudinal variations. space may be remarkably persistent and it occurs
Generally, Ptilothamnion sphaericum occurs from because the environmental conditions are too harsh,
middle to lower intertidal as a discrete species in allowing persistence of only those species that are
seaweeds communities characteristic in sandy rocky resistant o resilient to disruption or tolerant to stress.
(Table 1, Fig. 2D, G) like populations of Distinguishing feature of P. sphaericum, as
27P. Diaz Tapia & I. Barbara
Table 2
Field seasonal study (2002-2004) of Ptilothamnion sphaericum in four populations from three Galician localities: Playa de Seaia, Playa
de Barrañán and Playa de Barizo. Presence conditions: bur=buried, no=not observed.
2000 2001 2002 2003 2004 2005
Dec Jun Feb Aug Sep Nov Dec Jan Feb Mar Abr May Jun Aug Sep Oct Nov Dec Apr abr
Playa de Presence and
Seaia size (cm) 2 2 2,5 bur bur bur 2 bur 2,5
(middle Polysporangia
intertid al) (%) 20 no no - - - 5 - 5
Playa de Presence and
Barrañán size (cm) 1,1 no no 1,5 0,8 1 1 0,7
(subtidal, -1 Polysporangia
metre) (%) 5 - - 80 5 no no no
Playa de Presence and
Barrañán size (cm) 0,4 1,5 2 bur 0,5 0,4 0,4 0,7
(lower Polysporangia
intertidal) (%) no 20 no no no no no
Playa de Presence and
Barizo size (cm) 0,5 0,5 no 0,5 no no 1,2 1
(lower Polysporangia
intertidal) (%) 10 No - no - - 5 -
development of a wide system of prostrate axes with latidudes is lower than the one of the NW-Spain, from
numerous rhizoids and erect axes that surface through 11ºC to 18ºC.
the sand, explain that it be a competitive species in Incomplete or asexual life histories, usually allied
stressed sandy-rocky habitats. Thereby, Ptilothamnion to remarkable powers of regeneration are common in
sphaericum forms monospecific populations (Table 1, cespitose algae living in sandy and rocky habitats
Fig. 2E, F) in some Galician localities. In the Playa de (Norton et. al 1982) and is in agreement with the
Seaia (Fig. 2A, B) P. sphaericum covers the middle growth strategy of P. sphaericum. Sexual phases are
intertidal rocks where it develops an extensive band unknown in P. sphaericum (Maggs & Hommersand
over Lithophyllum incrustans (Fig. 2A, E) and tubes of 1993) however is necessary to stand out that in the
polychaetes (Fig. 2F), with few accompanying species Playa de Barrañán (November 2002) we found some
like Rhodothamniella floridula, Pterocladiella apical filaments bearing unfertilized procarps which
melanoidea, etc. In the Playa de Barrañán dense turfs were anomalous and miscarried in appearance.
of P. sphaericum (Fig 2C) has only been observed in
the lower intertidal. Seasonality of the populations
In the Playa de Seaia (Fig. 2A, B) Ptilothamnion
Reproduction and phenology sphaericum covers the middle intertidal rocks where it
According to Maggs & Hommersand (1993), develops an extensive band over Lithophyllum
individuals obtained by cultures of spores have not incrustans (Fig. 2A, E) and tubes of polychaetes (Fig.
developed sexual structures and populations, 2F), with few species like Rhodothamniella floridula
apparently, reproduced by extensive propagation of and Pterocladiella melanoidea. P. sphaericum forms a
prostrate axes followed by fragmentation of thalli. dense and stable population that can be buried by 1
Polysporangia are the unique known reproductive meter of sand during several months (Fig. 2B, D).
structures. In the Atlantic coast of the Iberian Only few days per years the sand was withdrawed
Peninsula, we found polysporangia from January to from the rocks of Seaia beach, in parallel to
April, September, November and December, and none southwestern swell and wind. Hence that populations
observations of them in the hot season. In the of Seaia was only observed unburied in February, April
populations of Barrañán, Seaia and Barizo we found and November, however P. sphaericum seen to be
polysporangia in few months (Table 2) being abundant present all months of the period and it survived long
in January, February and November. In the Brithis buried time, since always the sustratum was unburied
Isles, Maggs & Hommersand (1993) observed of sand we collected alive individuals of P.
polysporangia in March and Augoust, which could be sphaericum.
close to Galicia since the temperature in August in high Since the first collection in Seaia (February 2002)
28Biology, Populations and Distribution Area of the European Endemic Species Ptilothamniom Sphaericum (Ceramiales, Rhodophyta) in the Iberian Peninsula.
Table. 3
Culture in laboratory (2003-2004) of Ptilothamnion sphaericum from two Galician localities: Playa de Seaia and Playa de Barrañán.
Individual conditions: liv=live, dyi=dying, dea=dead.
Photoperiod 2003 2004 2005
light:dark Feb Mar Apr May Jun Sep Nov Dec Feb Jun Jul Oct Jan Apr
9:15 liv liv liv dyi dea
Playa de Seaia 6:18 liv liv liv dea
(middle intertidal)
1:23 liv liv liv liv liv liv liv liv liv liv liv dyi dea
1:23 liv liv liv liv liv liv dyi dyi
9:15 - liv dyi dea dea
Playa de Barrañán
(lower intertidal) 6:18 - liv dyi dyi dyi dea
1:23 - liv liv liv liv liv liv liv liv dyi dyi dyi dea
neither decline of the area occupied by P. sphaericum sphaericum was observed in the mayority of the
no changes in location of the original population was months. The thalli were 0,7-1,5 cm long and no
detected. In adition, erec axes are longer (2,5 cm long) seasonal variations were detected. In lower intertidal
than the others localities (Table 2). In contrast, the and upper subtidal was present all period with little
apical cells from Seaia are more pale in colour (lower variations in abundance; however in subtidal
pigmentation) than the ones collected in other populations of Ahnfeltia plicata, from December 2002
localities, conceivably, due to recent propagation of to March 2003, P. sphaericum was unmonitored owing
erect axes is produced when the sustratum is unburied, to A. plicata was saturated by fuel oil from the
which is only during one or two weeks. Erects axes oiltanker "Prestige" (Bárbara 2002). In three months
remain dormant during long buried periods, so growth the thalli were almost cleaned and the abundance of A.
and reproduction run slow in the Ptilothamnion plicata and its epiphytes were similar to the original
sphaericum populations. It can be possible that the one (Díaz Tapia & Bárbara, 2004).
propagation carried out when thallus of P. sphaericum Barrañán's tuft growing in culture at 6:18 and 9:15
are uncovered by sand, so if P. spaericum is collected light:dark photoperiods exhibted symptoms of
one or two days after the sand has been withdraw from deterioration at 1 month and no survived more than 3-
the substratum the apical cells are pale in colour. 4 months (Table 3). Similarly to the Playa de Seaia,
Polysporangia are scarce and inmature after two or individuals longer surviving from Barrañán were
three days unburied and its development agreement to grown at 1:23 light:dark photoperiod; they lived in
the intesive asexual and vegetative propagation culture no more than 20 months.
mentioned by Norton et al (1982) for cespitose algae In the Playa de Barizo, Ptilothamnion sphaericum
living in sandy and rocky habitats. is known since December 2000 when the species was
To test the ability survival of Ptilothamnion new record from Spain (Bárbara et al. 2001). From
sphaericum in stressed sandy habitats, tufts from the June 2001 to April 2005 we sampled (January,
Playa de Seaia were cultured in laboratory (Table 3, February, April, May, June and September) the sandy
Fig. 4H). Individuals growing at 6:18 and 9:15 rocky habitats of Barizo beach (Ahnfeltia plicata and
light:dark photoperiods exhibted symptoms of Rhodothamniella floridula vegetation), but P.
deterioration at 2-3 month and they not survived more sphaericum was only found in June 2001, January
than 4 months. Individuals longer surviving were 2003 and April 2004. In general, collection shortages
grown at 1:23 light:dark photoperiod. They lived in of P. sphaericum is due to burying by sand. Individuals
culture for 21 months (Table 3) since lower of P. sphaericum were small (1,2 cm long) and usually
temperature, irradiance and photoperiod were similar vegetative, except in December 2000 and April 2004.
to its habitat and explain why P. sphaericum is a
successful species that colonize sandy rocky where
sand buried the tufts of the algae during several ACKNOWLEDGEMENTS
months. We thank to Rita Araújo (University of Oporto,
In the Playa de Barrañán Ptilothamnion Portugal) and Estíbaliz Berecibar (University of
29P. Diaz Tapia & I. Barbara
Algarve, Portugal) for their support with the field- 275.
work. Likewise we thank two anonymous referees for Díaz Tapia, P. & Bárbara, I. 2004. Vegetación algal de
their suggestions and corrections to the manuscript. ambientes rocoso-arenosos de Galicia y su relación
con el vertido del Prestige. Bol. Inf. Soc. Esp.
Ficol., 31: 28-33.
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