Alba Vergés

Diversity of bladed Bangiales (Rhodophyta) in western Mediterranean: recognition of the genus Themis and descriptions of T. ballesterosii sp. nov., T. iberica sp. nov., and Pyropia parva sp. nov.

The diversity of the bladed species of the red algal order Bangiales from the Iberian Mediterranean shores has been reassessed after a detailed study of this region. Prior to this study, 11 bladed species of Bangiales had been reported from Mediterranean waters: Porphyra atropurpurea, P. cordata, P. coriacea, P. dioica, P. linearis, P. purpurea, P. umbilicalis, Pyropia leucosticta, Pyropia koreana (as P. olivii), Py. elongata (as P. rosengurttii) and Py. suborbiculata. A combined analysis of the nuclear nSSU and the plastid rbcL genes together with detailed morphological studies has confirmed the presence of species within the genera Porphyra and Pyropia and also revealed a third, undescribed genus, Themis gen. nov. Porphyra linearis, Pyropia elongata and the introduced Pyropia koreana had been previously listed for the Mediterranean and were recorded in this study. An additional four species, including the introduced Pyropia suborbiculata and three new species: Pyropia parva sp. nov., Themis ballesterosii sp. nov., and Themis iberica sp. nov. were also observed. Hence, most of the Porphyra species traditionally reported along these shores were not reported in this survey. This new floristic Bangiales composition confirms the importance of the Mediterranean basin as a hotspot for biodiversity, possible endemics of ancient origin and high proportion of introductions. Our data also continue to confirm the extent of Bangiales diversity at regional and worldwide levels.

A reassessment of the foliose Bangiales (Rhodophyta) in the Balearic Islands including the proposed synonymy of Pyropia olivii with Pyropia koreana

Abstract A taxonomic reevaluation of the foliose Bangiales placed in the genus Porphyra from the Balearic Islands, based on the historical and recent collections, has resulted in a new floristic composition of this group. The molecular, morphological, and karyological analysis reveals that for these islands, there are no Porphyra species, and only two members of the genus Pyropia are present: Pyropia elongata and Pyropia koreana. The sequence data of the rbcL plastid gene indicate that Pyropia olivii and Pyropia koreana are conspecific. We, therefore, propose the synonymy of Pyropia olivii with Pyropia koreana, which is the taxon with nomenclatural priority. The study with the fresh and old material has revealed that neither Porphyra umbilicalis nor Pyropia leucosticta are present in this area and that most of the old herbarium material that has gone under this name belongs to Pyropia elongata.

Life histories of Predaea ollivieri and P. pusilla (Nemastomatales, Rhodophyta)

The life histories of Predaea ollivieri J. Feldmann and P. pusilla (Berthold) J. Feldmann were studied in vitro. In P. ollivieri, carpospore germination was unipolar, and sporophytes were formed of sparsely branched uniseriate filaments. In P. pusilla, carpospore germination was bipolar, and sporophytes were formed of uniseriate filaments consolidated in a pseudoparenchymatous crust. Carpospore development was observed in both species when irradiances ranged between 5–40 μmol m−2 s−1 combined with seawater temperature of 16, 18 or 21°C; no development was observed at 80 μmol m−2 s−1 or 14°C. Tetrasporophytes of P. ollivieri developed tetrasporangia in summer, autumn, winter and spring conditions. When the irradiance and temperature were high (40 μmol m−2 s−1, 21°C; hot-summer), bisporangia were produced instead of tetrasporangia. In summer and autumn conditions, some tetraspores gave rise to dioecious gametophytes, with male and female structures identical to those of the mother plant. In P. pusilla, tetrasporangia were not observed, but monosporangia were present in summer, autumn, winter and spring conditions, and bispores in hot-summer conditions. In late spring and summer, some monospores gave rise to dioecious gametophytes, with male and female structures identical to those of the mother plant. In both species, all types of spores were capable of producing new sporophytes that repeat this process for several successive generations. This capacity of sporophyte self-generation appears to promote survival by increasing the number of individual plants of the population.

Vegetative and reproductive morphology of Kallymenia patens (Kallymeniaceae, Rhodophyta) in the Mediterranean Sea

Abstract Reproductive morphology of the Mediterranean red alga Kallymenia patens is described for the first time, confirming its position in the genus. K. patens is characterized by a non-procarpic female reproductive apparatus, carpogonial branch systems consisting of supporting cells bearing both three-celled carpogonial branches and subsidiary cells that lack a hypogynous cell and carpogonium; fusion cells develop numerous connecting filaments, and tetrasporangia are scattered over the thallus and are probably cruciately divided. Old fertile spathulate specimens of K. patens are morphologically similar to K. spathulata, but they can be distinguished by the length of spathulated proliferations (up to 0.6 cm and 6 cm, respectively), the length of inner cortical cells (up to 70 and 30 μm, respectively), and the gonimoblast location (in proliferations from the perennial part of the blade and over all the thallus surface, respectively).

Kallymenia crouaniorum (Kallymeniaceae, Rhodophyta), a new red algal species from the Laminaria hyperborea understorey community

In this paper we describe Kallymenia crouaniorum Vergés & Le Gall, sp. nov. (Kallymeniaceae), a new marine red alga from the north-eastern Atlantic Ocean. rbcL and LSU sequences of this species, previously misidentified in the field as Kallymenia reniformis, diverged from those of other Kallymenia species by at least 7.5% and 5.2%, respectively. Kallymenia crouaniorum also has a set of distinctive vegetative and reproductive characteristics, including a deeply lacerate frond, a short stipe, dentate margins, large cortical cells up to 110 μm in diameter, highly refractive stellate medullary cells with arms up to 1000 μm in length, and a monocarpogonial branch system. Molecular phylogenies inferred from rbcL and LSU data indicated, albeit with weak support, that this new species is a sister taxon of a lineage encompassing the generitype K. reniformis, as well as most species of Kallymenia included in the phylogenetic analysis. The main morphological characters that delineate monocarpogonial Kallymenia species are presented. Moreover, after reviewing the literature and several herbarium specimens, we found in the Weber-van Bosse Herbarium a specimen collected at Roscoff in August 1894 with the anatomical characters of the species described here, confirming that this newly described species has in fact been overlooked and is not a recent introduction.

Phylogenetic Analyses Support Recognition of Ten New Genera, Ten New Species and 16 New Combinations in the Family Kallymeniaceae (Gigartinales, Rhodophyta)

Abstract The current study presents the most detailed multigene phylogenetic assessment of the red algal family Kallymeniaceae to date emphasising the floras of Australia (220 specimens), Europe (19 specimens) and North America (54 specimens). Toward a natural classification and in light of our phylogenetic results, we propose numerous taxonomic changes including the recognition of ten new genera: Austrokallymenia Huisman & G.W.Saunders; Glaphyrymeniopsis Kraft & G.W.Saunders; Huonia G.W.Saunders; Leiomenia Huisman & G.W.Saunders; Metacallophyllis A.Vergés & L.Le Gall; Nothokallymenia A.Vergés & L.Le Gall; Rhipidomenia G.W.Saunders; Thalassiodianthus G.W.Saunders & Kraft; Tytthomenia G.W.Saunders; and Verlaquea L.Le Gall & A.Vergés. The proposals of new genera are accompanied by 16 new combinations of which half are for species from the formerly species-rich genus Kallymenia. Approximately 50 undescribed genetic species were uncovered, of which only ten are now formally named, five of which are type species for new genera: Glaphyrymeniopsis mollis Kraft & G.W.Saunders, Huonia sandersonii G.W.Saunders, Leiomenia lacunata Huisman & G.W.Saunders, Thalassiodianthus incrassatus G.W.Saunders & Kraft and Tytthomenia barrettii G.W.Saunders. The remaining five are Austrokallymenia rebeccae G.W.Saunders & Kraft, A. roensis Huisman & G.W.Saunders, Leiomenia imbricata Huisman & G.W.Saunders, Meredithia compaginata G.W.Saunders, and Verlaquea fimbriata G.W.Saunders. Also described and illustrated for the first time are reproductive features of the northeastern-Pacific Euthora timburtonii Clarkston & G.W.Saunders, which has been known until now only from molecular studies of vegetative thalli. Despite advances made by our work, the need for considerably more taxonomic investigation in this diverse family is demonstrated, particularly within the presently constituted genus Callophyllis.

Rhodymeniocolax mediterraneus sp. nov. (Rhodymeniales, Rhodophyta), parasitic on Rhodymenia ardissonei from the western Mediterranean Sea

A. Vergés, C. Izquierdo and M. Verlaque. 2005. Rhodymeniocolax mediterraneus sp. nov. (Rhodymeniales, Rhodophyta), parasitic on Rhodymenia ardissonei from the western Mediterranean Sea. Phycologia 44: 510–516. Rhodymeniocolax mediterraneus Vergés, Izquierdo & Verlaque sp. nov., a sublittoral adelphohemiparasite of Rhodymenia ardissonei from the western Mediterranean Sea, is described. The distinctive vegetative and reproductive characteristics of the new species are: plants generally less than 6 mm in height with terete to compressed axes up to 1(−2) mm broad; a cortex composed of one to three layers of cells; spermatangia arranged in sori located on the subapical part of the thallus; cystocarps laterally positioned on branches; and cruciate tetrasporangia borne in sori. A comparison is made with other parasitic genera of Rhodymeniales and other species of Rhodymeniocolax.

The morphology and reproductive structures of Mediterranean species of the genus Nemastoma J. Agardh, nom. cons. (Nemastomataceae, Nemastomatales): Nemastoma dichotomum and N. dumontioides

Abstract We investigated a collection of Nemastoma J. Agardh, nom. cons. (Nemastomatales, Rhodophyta), including the Mediterranean type material of species described by J. Agardh, Kützing and Ercegovic, and recent specimens from the Mediterranean Sea, Adriatic Sea and northeastern Atlantic Ocean. Based on their habit and vegetative and reproductive structures, we confirm that: (i) all the Mediterranean specimens studied belong to the genus Nemastoma; (ii) two species of Nemastoma co-exist in the Mediterranean Sea: (a) N. dichotomum, which is characterized by great plasticity of habit, a cartilaginous thallus in its basal and middle parts, and presumed reproduction exclusively by apomixis; and (b) N. dumontioides, which is characterized by a regularly pseudodichotomous, saccate-membranous thallus, and which reproduces both sexually and probably apomictically; and (iii) the Atlantic specimens attributed to N. dichotomum belong to other genera, and so, N. dichotomum is probably endemic to the Mediterranean Sea. Thus, three species described by Kützing have been reduced to varieties of Nemastoma dichotomum: (a) var. biasolettianum (Kützing) Rodríguez-Prieto, Verlaque et Vérges comb. nov. et stat. nov., with ligulate upper parts, (b) var. caulescens (Kützing) Rodríguez-Prieto, Verlaque et Vérges comb. nov. et stat. nov., with wedge-shaped upper parts, and (c) var. incrassatum (Kützing) Rodríguez-Prieto, Verlaque et Vérges comb. nov. et stat. nov., with spathulate upper parts. Finally, Nemastoma constrictum and N. constrictum var. longitrichogynum are placed in synonymy with N. dichotomum var. caulescens.

Rhytimenia, a new genus of red algae based on the rare Kallymenia maculata (Kallymeniaceae, Rhodophyta)

Abstract: Morphological and molecular analyses of newly collected samples of the rare Kallymenia maculata, described originally from specimens collected during the Siboga Expedition but never recollected, indicated that the species was incorrectly placed in the genus Kallymenia and did not conform to any existing genera. The new genus Rhytimenia is described to accommodate this species, distinguished morphologically by its gelatinous, bullate thallus; angular (in surface view) outer cortical cells; wholly filamentous medulla lacking ganglionic or refractive cells; and monocarpogonial branch system with spherical subsidiary cells. The autonomy of Rhytimenia was supported by molecular analyses (COI-5P, nuclear ribosomal large subunit gene, rbcL) that resolved K. maculata as only distantly allied to other Kallymeniaceae and clearly incorrectly assigned to Kallymenia based on the position of the generitype Kallymenia reniformis. A second species, Rhytimenia cerebriformis (basionym Sebdenia cerebriformis), was included in the new genus based on molecular analyses and morphological similarities with Rhytimenia maculata but differing in the presence of multiple marginal cartilaginous holdfasts.

A new cryptic species in the Mediterranean Sea; molecular and morphological insights into bladed species of the Bangiales

Bacteria associated with 2 macroalgae growing in the Kiel Fjord (Baltic Sea) were investigated seasonally over two years by scanning electron microscopy and cultivation methods. Seasonal variations and significant differences between both macroalgal species with respect to the associated bacteria were observed. 166 bacterial strains were isolated from the macroalgae and classified by phylogenetic analysis of 16S rRNA gene sequences. The strains formed 82 phylotypes according to sequence similarities of499.0%. Samples from Fucus vesiculosus revealed 43 and from Delesseria sanguinea 57 bacterial phylotypes. They affiliated to Actinobacteria, Alphaproteobacteria, Bacilli, Betaproteobacteria, Flavobacteria, Gammaproteobacteria, and Sphingobacteria. Following the assumption that chemical interactions rule the bacteria-macroalga associations, we tested the biological activity of both macroalgae and isolated bacterial strains against a panel comprising standard and ecologically relevant microorganisms (Gram-positive and Gram-negative bacteria, including macroalgal pathogens and surface associated strains, and a yeast). Both macroalgae presented inhibitory activity against at least one microorganism, but overall the inhibitory activities were low. In contrast, all extracts stimulated growth of many of the tested bacteria. While growth stimulation was common concerning bacteria associated with macroalgae, no stimulation was shown for the standard set of bacteria (with exception of one case of stimulation of the plant pathogen Erwinia amylovora). Regarding the potential biological activity of microorganisms associated with macroalgae, more than 60% of the bacterial phylotypes inhibited the growth of at least one microorganism. A higher proportion of strains showed antimicrobial activity against the set of bacteria associated with macroalgae as compared to standard set of microorganisms. Certain phylotypes are consistently found as epiphytes, suggesting their specific association with macroalgae. The presented positive and negative effects of macroalgal extracts on growth of macroalga-associated bacteria, significant bacterial activity against macroalgal pathogens and competitors, and potential degradative capabilities support the assumption that complex chemical interactions shape the bacteria-macroalga relationships.Ecophysiological characteristics of algae and their acclimation potential to environmental stress are often assessed by quenching analyses of chlorophyll fluorescence (qP and NPQ) and changes to the parameters of Photosynthesis vs. Irradiance (P/ E) curves such as , rETRmax and Ek. Using chlorophyll fluorescence in laboratory experiments P/E curves are either measured as Rapid or Steady State Light Curves (RLC, LC). Here, effects of short-term emersion on the photo-response patterns of four brown macroalgae collected from different shore levels (Ascophyllum nodosum, Sargassum muticum, Fucus serratus, Laminaria digitata) were compared by measuring both RLC and LC. When LC were applied, photosynthetic performance was significantly enhanced in A. nodosum and F. serratus upon air exposure as shown by an increase in qP, rETRmax and Ek, whereas short-term emersion had no impact on photosynthetic parameters of S. muticum and L. digitata. NPQmax was significantly higher only in the lower shore species L. digitata during emersion. However relative changes in NPQ as a function of rETR were reduced in A. nodosum, F. serratus and S. muticum, but remained unaffected in L. digitata. Such results were not obtained from the application of RLC. None of the species developed their potential NPQmax as determined from LC. Some artifacts were further generated by RLC for F. serratus and L. digitata resulting in a contrary outcome as photosynthetic performance appeared to be significantly reduced upon exposure to air which was associated with a higher ‘‘NPQmax’’. These results indicate that emersion may not be the main abiotic stressor for intertidal brown seaweeds. Moreover, when photo-response patterns are used as a measure of the extent of stress experienced by a brown macroalgae, the LC protocol should be applied since the application of RLC did not always reveal environmental impacts on photosynthesis.