Reproductive phenology of three species of Gelidiales (Rhodophyta) in two macroalgal communities from Tenerife (Atlantic Ocean, Canary Islands, Spain)

The reproductive phenology of three species of Gelidiales, Gelidium canariense, Gelidium arbuscula and Pterocladiella capillacea, was analysed seasonally for a period of one year in two localities on the West coast of Tenerife (Atlantic Ocean, Canary Islands, Spain). Considerations are provided on sex ratio, maximum length and branch order of uprights and on the length of the thalli for each sexual and asexual phase of the Canary Islands populations. The three species were characterized by a high percentage of tetrasporophytes, while female and male gametophytes have been observed only in little proportion. Only G. canariense showed gametophytes in all seasons while the occurrence of gametophytes in G. arbuscula and Pterocladiella capillacea demonstrated a clear seasonality.La fenología reproductiva de tres especies de Gelidiales, Gelidium canariense, Gelidium arbuscula y Pterocladiella capillacea, ha sido analizada estacionalmente por un periodo de un año en dos localidades de la costa este de Tenerife (Oceano Atlántico, Islas Canarias, España). Se realizan consideraciones sobre sex ratio, longitud máxima y orden de ramificación de los ramets y se aporta información sobre la longitud del talo por cada fase sexual y asexual de las poblaciones canarias. Las tres especies se caracterizan por presentar un elevado porcentaje de tetrasporofitos, mientras que los gametofitos masculinos y femeninos han sido observados en proporciones reducidas. Sólo G. canariense presenta gametofitos en todas las estaciones, mientras que en G. arbuscula y Pterocladiella capillacea demostraban una clara estacionalidad

Fenología reproductiva de tres especies de Gelidiales (Rhodophyta) en dos comunidades de macroalgas de Tenerife (Océano Atlántico, Islas Canarias, España)

The reproductive phenology of three species of Gelidiales, Gelidium canariense, Gelidium arbuscula and Pterocladiella capillacea, was analysed seasonally for a period of one year in two localities on the West coast of Tenerife (Atlantic Ocean, Canary Islands, Spain). Considerations are provided on sex ratio, maximum length and branch order of uprights and on the length of the thalli for each sexual and asexual phase of the Canary Islands populations. The three species were characterized by a high percentage of tetrasporophytes, while female and male gametophytes have been observed only in little proportion. Only G. canariense showed gametophytes in all seasons while the occurrence of gametophytes in G. arbuscula and Pterocladiella capillacea demonstrated a clear seasonality.La fenología reproductiva de tres especies de Gelidiales, Gelidium canariense, Gelidium arbuscula y Pterocladiella capillacea, ha sido analizada estacionalmente por un periodo de un año en dos localidades de la costa este de Tenerife (Oceano Atlántico, Islas Canarias, España). Se realizan consideraciones sobre sex ratio, longitud máxima y orden de ramificación de los ramets y se aporta información sobre la longitud del talo por cada fase sexual y asexual de las poblaciones canarias. Las tres especies se caracterizan por presentar un elevado porcentaje de tetrasporofitos, mientras que los gametofitos masculinos y femeninos han sido observados en proporciones reducidas. Sólo G. canariense presenta gametofitos en todas las estaciones, mientras que en G. arbuscula y Pterocladiella capillacea demostraban una clara estacionalidad

Restructuring of the "Macaronesia" biogeografic unit: a marine multi-taxon biogeographical approach

The Azores, Madeira, Selvagens, Canary Islands and Cabo Verde are commonly united under the term “Macaronesia”. This study investigates the coherency and validity of Macaronesia as a biogeographic unit using six marine groups with very different dispersal abilities: coastal fishes, echinoderms, gastropod molluscs, brachyuran decapod crustaceans, polychaete annelids, and macroalgae. We found no support for the current concept of Macaronesia as a coherent marine biogeographic unit. All marine groups studied suggest the exclusion of Cabo Verde from the remaining Macaronesian archipelagos and thus, Cabo Verde should be given the status of a biogeographic subprovince within the West African Transition province. We propose to redefine the Lusitanian biogeographical province, in which we include four ecoregions: the South European Atlantic Shelf, the Saharan Upwelling, the Azores, and a new ecoregion herein named Webbnesia, which comprises the archipelagos of Madeira, Selvagens and the Canary Islandsinfo:eu-repo/semantics/publishedVersio

Distribución de los epífitos en "Cystoseira tamariscifolia" (Hudson) Papenfuss ("Fucales, Phaeophyta") en punta de Gáldar (Gran Canaria, Islas Canarias)

Se ha estudiado la distribución de los epífitos, con exclusión de diatomeas, sobre Cystoseira tamariscifolia (Hudson) Papenfuss, distinguiendo tres zonas en el forófito: disco, estipe y ramas. Se reconoce un total de 72 especies epífitas. El estipe es la región más epifitada, con 56 especies; seguida por las ramas, con 44; mientras que el disco es el menos epifitado, con 18. Por grupos son las rodofitas las más representadas en las tres zonas del forófito, lo que concuerda con la dominancia de este grupo en el conjunto de la flora bentónica de las Islas Canarias.Epiphyte algal distribution on Cystoseira tamariscifolia has been studied. Diatoms were excluded. The host was studied in three areas: holdfast, stipe and branches. 72 species were identified: 56 on the holdfast, 44 on the stipe and 18 on the branches. Rhodophyta is the more represented group, in keeping with the preponderaney of this group in all the benthic marine flora of the Canary Islands

Seagrass responses to nutrient enrichment depend on clonal integration, but not flow-on effects on associated biota

We determined physiological and morphological responses of the seagrass Cymo - docea nodosa and associated epiphytes and epifauna to water column nutrient enrichment, and investigated whether responses were modulated by the clonal integration of the seagrass. Nutrient levels were elevated, relative to 'ambient' plots, in 'large' (∼10 to 100×) and 'moderate' (∼5 to 10×) enrichment plots, in a seagrass meadow off the south coast of Gran Canaria. Clonal integration was severed in half the plots, isolating them from adjacent shoots. Seagrass shoot density, above-ground biomass and leaf surface were lower in fertilized than ambient plots when clonal integration was severed. In the plots where clonal integration was maintained, no differences in shoot density were observed between fertilized and ambient plots, while differences in aboveground biomass and leaf surface were exclusively observed between 'large' enrichment and 'ambient' plots. Seagrass above-ground tissues accumulated P, but not N, when clonal integration was maintained. The N content, but not P content, of below-ground parts increased with fertilization. The content of soluble sugars in seagrass tissues decreased under nutrient enrichment; this decay was, however, buffered when clonal integration was maintained. Grazing bites on leaves increased with nutrient enrichment regardless of the clonal integration. Epiphytic loads increased at elevated nutrient levels irrespective of the clonal integration. The abundance and richness of epifauna were larger on 'moderate' relative to 'ambient' and 'large' enrichment plots, independently of clonal integration. In conclusion, while the physiological and morphological responses of C. nodosa to nutrient enrichment depended on the maintenance of clonal integration, flow-on effects on epiphytes and epifauna were independent of the clonal integration of the seagrass. © Inter-Research 2013.Peer Reviewe