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Repositorio da Universidade dos Açores (8.559 recursos)

O Repositório Institucional da Universidade dos Açores desenvolvido no âmbito do projecto RCAAP.

DB - Artigos em Revistas Internacionais / Articles in International Journals

Mostrando recursos 1 - 20 de 134

  1. Development of conceptacles in Amphiroa (Corallinales, Rhodophyta)

    Rosas-Alquicira, Edgar; Riosmena-Rodríguez, Rafael; Hernández-Carmona, Gustavo; Neto, Ana I.
    Here, we describe the development of sporangial and gametangial conceptacles for Amphiroa beauvoisii and A. vanbosseae; sporangial conceptacles only for A. misakiensis; and gametangial conceptacles only for A. cryptarthrodia and A. rigida. The descriptions are based on the observation of histological preparations obtained from 112 specimens collected from the Gulf of California, in Mexico, and the Azores archipelago of Portugal. Information on the development of the sporangial conceptacle pore and conceptacle senescence is here described and illustrated for the first time. Four development patterns were observed: two for sporangial conceptacles; one for spermatangial conceptacles; and one for carposporangial conceptacles. The...

  2. Effects of density versus size on grazing by a key exploited herbivore

    Martins, Gustavo M.; Prestes, Afonso L.; Neto, Ana I.
    Fishing decreases the biomass of target species via reduction in the numbers and/or size of individuals. In natural systems, the strength of biological interactions, including predator-prey dynamics, are often density or size-dependent. Hence, changes in the numbers or size of key taxa may be expected to influence biological interactions but their effects do not need to be identical. Here we compare the effects of biomass reduction in populations of the exploited limpet Patella candei. Biomass removal was experimentally achieved by either removing individuals (density reduction) or by replacing large by small individuals (size reduction), while controlling for total limpet biomass...

  3. A combined barcode and morphological approach to the systematics and biogeography of Laurencia pyramidalis and Laurenciella marilzae (Rhodophyta)

    Machín-Sánchez, María; Le Gall, Line; Neto, Ana I.; Rousseau, Florence; Cassano, Valéria; Sentíes, Abel; Fujii, Mutue T.; Díaz-Larrea, Jhoana; Prud’homme van Reine, Willem F.; Bonillo, Céline; Gil-Rodríguez, Maria C.
    In the present study we undertook an integrative approach, using both morphological and molecular data (COI-5P + rbcL), to assess the presence of Laurencia pyramidalis in Lusitanian Macaronesia.We studied type material of L. pyramidalis from the herbarium of the Naturalis Biodiversity Center, the Netherlands, and designated a lectotype and syntypes. Vegetative and reproductive features of L. pyramidalis were observed and we included a specimen from the type locality in our molecular analyses.We also investigated the geographical distribution of Laurenciella marilzae, a species recently described from the Canary Islands. Barcode sequences (COI-5P and rbcL) were generated for L. pyramidalis from the...

  4. Cytotoxic meroterpenoids from the macroalga Cystoseira abies-marina

    Gouveia, Vera L. M.; Seca, Ana M. L.; Barreto, Maria do Carmo; Neto, Ana I.; Kijjoa, Anake; Silva, Artur M. S.
    Two new meronorsesquiterpenes (cystoazorones A and B) and two new meroditerpenes (cystoazorols A and B), along with benzoic acid were isolated from the brown macroalga Cystoseira abies-marina. The structures of the new compounds were established by 1D and 2D NMR as well as HRMS spectral analysis. The in vitro cytotoxicity and antioxidant activity of the isolated compounds were also evaluated. Cystoazorones A and B, and cystoazorol A exhibited in vitro growth inhibitory activity against HeLa cells. The HeLa cell line in log phase was found to be more sensitive to cystoazorol A than when it was in lag phase. Cystoazorol...

  5. New foliose and gelatinous red macroalgae (Rhodophycota) from the Azores: morphological and geographical observations.

    Neto, Ana I.; Terra, Marlene R.; Haroun, Ricardo J.
    The following four species of foliose and gelatinous red algae (Rhodophycota) are newly recorded for the Azores archipelago (North Atlantic Ocean): Gracilaria multipartita (Clemente) Harvey, Meristotheca decumbens Grunow (Solieriaceae), Asteromenia peltata (W.R. Taylor) Huisman and A.J.K. Millar (Rhodymeniaceae), and Agardhinula browneae (J. Agardh) De Toni (Faucheaceae). The species are described, and information on reproductive status, ecology and biogeographical relationships is provided.

  6. Botryocladia chiajeana and Botryocladia macaronesica sp. nov. (Rhodymeniaceae, Rhodophyta) from the Mediterranean and the eastern Atlantic, with a discussion on the closely related genus Irvinea.

    Afonso-Carrillo, Julio; Rodríguez-Prieto, Conxi; Boisset, Fernando; Sobrino, Cristina; Tittley, Ian; Neto, Ana I.
    Specimens from the eastern Atlantic, Mediterranean and Adriatic seas previously reported as Botryocladia chiajeana showed differences in morphology, and re-examination of Meneghini's original collection of Chrysymenia chiajeana (basionym B. chiajeana) revealed that only the Mediterranean and Adriatic specimens are in agreement with the original protologue, whereas plants reported from the eastern Atlantic are recognised here as Botryocladia macaronesica Afonso-Carrillo, Sobrino, Tittley & Neto sp. nov. The vegetative and reproductive morphology of western Mediterranean plants is examined in detail for the first time, and B. chiajeana is characterised by the following combination of features: solid axes bearing frequently dichotomously branched vesicles,...

  7. Rocky intertidal community structure in oceanic islands : scales of spatial variability

    Martins, Gustavo M.; Thompson, Richard C.; Hawkins, Stephen J.; Neto, Ana I.; Jenkins, Stuart R.
    Copyright © Inter-Research 2008.

  8. Phylogenetic appraisal of the genus Platoma (Nemastomatales, Rhodophyta), including life history and morphological observations on P. cyclocolpum from the Azores.

    Gabriel, Daniela; Parente, Manuela I.; Neto, Ana I.; Raposo, Monica; Schils, Tom; Fredericq, Suzanne
    The red algal genus Platoma Schmitz (Schizymeniaceae, Nemastomatales) with type Platoma cyclocolpum (Montagne) Schmitz was originally described from the Canary Islands. Life history studies were conducted on P. cyclocolpum from the Azores under 10uC/8:16 light (L):dark (D), 15uC/16:8 L:D, and 23uC/natural daylight regimes in culture. Three nonreproductive modes of thallus development resulted from germinating carpospores: (1) a permanent crust, (2) a filiform, nonfoliose erect thallus occasionally attached by a holdfast composed of cell aggregations, and (3) a filiform, nonfoliose erect thallus has been reported previously for populations from the Canary Islands, but the latter two have not been described before....

  9. Illegal harvesting affects the success of fishing closure areas

    Martins, Gustavo M.; Jenkins, Stuart R.; Hawkins, Stephen J.; Neto, Ana I.; Medeiros, André; Thompson, Richard C.
    Copyright © Marine Biological Association of the United Kingdom 2010.

  10. Taxonomic studies in the Schizymeniaceae (Nemastomatales, Rhodophyta): on the identity of Schizymenia sp. in the Azores and the generic placement of Nemastoma confusum

    Gabriel, Daniela; Schils, Tom; Parente, Manuela I.; Draisma, Stefano; Neto, Ana I.; Fredericq, Suzanne
    Comparative rbcL sequence analysis indicates that the species going under the name Schizymenia dubyi in the Azores should be referred to as S. apoda. Sequences of Schizymenia specimens from China and Namibia were also identified as S. apoda, of which the type locality is the Cape Province in South Africa. Schizymenia dubyi, described from Atlantic France, is clearly a distinct species that we here report for Japan and Sicily in the Mediterranean Sea. Both Schizymenia species, along with an unreported species from Japan, are distinct from S. pacifica described from Washington, in the Pacific Coast of North America. Secondary pit...

  11. Chemical study and biological activity evaluation of two Azorean Macroalgae: Ulva rigida and Gelidium microdon

    Silva, Madalena; Vieira, Luís M.; Almeida, Ana Paula; Silva, Artur M. S.; Seca, Ana M. L.; Barreto, Maria do Carmo; Neto, Ana I.; Pedro, Madalena; Pinto, Eugénia; Kijjoa, Anake
    Copyright: © 2013 Silva M, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credite.

  12. Exploitation of rocky intertidal grazers : population status and potential impacts on community structure and functioning

    Martins, Gustavo M.; Jenkins, Stuart R.; Hawkins, Stephen J.; Neto, Ana I.; Thompson, Richard C.
    Copyright © Inter-Research 2008.

  13. Intertidal rocky shore seaweed communities subject to the influence of shallow water hydrothermal activity in São Miguel (Azores, Portugal)

    Wallenstein, Francisco; Couto, Ruben P.; Torrão, Daniel F.; Neto, Ana I.; Rodrigues, Armindo; Wilkinson, Martin
    Copyright © Springer-Verlag Berlin Heidelberg and AWI 2012.

  14. Effects of coastal orientation and depth on the distribution of subtidal benthic assemblages

    Martins, Gustavo M.; Patarra, Rita F.; Álvaro, Nuno V.; Prestes, Afonso L.; Neto, Ana I.
    A better understanding of biological systems can only be gained if we understand what processes are important and how they operate to determine the distribution of organisms. Coastal orientation and depth can influence environmental conditions, including the degree of water motion and availability of light, which in turn may influence the horizontal and vertical patterns of organism distribution. Here, we used a mixed-model design to examine the effects of coastal orientation and depth on the structure of benthic assemblages by comparing the abundance and distribution of macroalgae and invertebrates in shallow and deep waters on the opposing coasts of Sa˜o...

  15. Linkages between rocky reefs and soft-bottom habitats: effects of predation and granulometry on sandy macrofaunal assemblages

    Martins, Gustavo M.; Faria, João; Rubal, Marcos; Neto, Ana I.
    The movement of animals and materials among habitats can have an important influence on the structure of assemblages. The nature of such linkages is, however, not always an obvious one. Here we examined the influence of rocky reefs on nearby sandy macrofaunal assemblages. A preliminary descriptive study confirmed the hypothesis that sediment granulometry differs in relation to distance to rocky reefs and so did the macrofaunal assemblage composition, and relative abundance of three of the most abundant taxa, and that this effect was generally consistent among locations. In addition, there was a significant effect of sediment structure on community structure...

  16. Coccolithophore species as indicators of surface oceanographic conditions in the vicinity of Azores islands

    Silva, Alexandra A.; Brotas, Vanda; Valente, A.; Sá, C.; Diniz, Tania; Patarra, Rita F.; Álvaro, Nuno V.; Neto, Ana I.
    During summer 2008 and spring 2009, surface oceanographic surveys were carried out around three islands of the Azores archipelago (Terceira, São Miguel and Santa Maria) to assess the phytoplankton distribution and associated physico-chemical processes. The Azores archipelago is a major feature in the biogeochemical North Atlantic Subtropical Gyre (NAST) province although its influence on the productivity of the surrounding ocean is poorly known. Surface phytoplankton was studied by microscopy and HPLC (High Precision Liquid Chromatography). The mean values for biomass proxy Chlorophyll a (Chla) ranged from 0.04 to 0.55 μg Lˉ¹ (Chla maximum = 0.86 μg Lˉ¹) and coccolithophores were...

  17. Enhancing stocks of the exploited limpet Patella candei d'Orbigny via modifications in coastal engineering

    Martins, Gustavo M.; Thompson, Richard C.; Neto, Ana I.; Hawkins, Stephen J.; Jenkins, Stuart R.
    It is widely recognised that microhabitats are important for a variety of marine organisms, yet this knowledge has rarely been applied in the construction of engineered structures as a means of enhancing biodiversity or populations of species at risk. Here we examined the influence of microhabitats on the distribution and survival of the exploited limpet Patella candei on natural shores before determining the effect of introducing such habitats to an artificial seawall. On natural shores individuals were associated with pits (a natural feature of volcanic rocky shores). Animals inhabiting pits showed reduced mortality and were smaller than those on open...

  18. A re-evaluation of Scinaia (Nemaliales, Rhodophyta) in the Azores.

    Léon-Cisneros, Karla; Riosmena-Rodriguez, Rafael; Neto, Ana I.
    The genus Scinaia in the Azores is re-evaluated based on historical and recent collections. A combination of morphological and anatomical diagnostic characters was used for species segregation, and a key for Azorean species determination is presented. Anatomical information associated to the hair development is described for the first time for the genus. The occurrence of S. furcellata and S. interrupta is confirmed for the archipelago. The presence of S. acuta is reported for the first time in the Azores, representing a spread from Australia to the N-Atlantic and specifically into the Macaronesian region. Its occurrence in the archipelago and the...

  19. On the occurrence of Mesophyllum expansum (Philippi) Cabioch et Mendoza (Melobesioideae, Corallinales, Rhodophyta) in the Mediterranean, the Canary Isles and the Azores.

    Athanasiadis, Athanasios; Neto, Ana I.
    We reviewed literature records, examined herbarium specimens and studied new collections referred to as Mesophyllum lichenoides from the Mediterranean and the North Atlantic, and report for the first time the presence of Mesophyllum expansum in the Canaries and the Azores. Both gametophytes and tetrasporophytes of M. expansum occur in the Canaries, while we found only tetrasporophytes (and sterile thalli) of the species in all other regions. We further consider the presence of M. lichenoides further south than Atlantic France in need of confirmation. A comparative study between these two species points to the number of rosette cells as the most...

  20. Subtidal Rocky Shore Communities of the Azores: Developing a Biotope Survey Method

    Wallenstein, Francisco; Neto, Ana I.; Álvaro, Nuno V.; Tittley, Ian
    At 23 sites selected randomly around the island of S o Miguel (Azores), video records were made at the depths of 5, 10, 15, 20, 25, and 30 m where a rocky substratum was present. Semiquantitative abundance data of the most common benthic organisms (algae and fixed/sedentary macroinvertebrates) were recorded in the vicinity of each depth reference point. Qualitative samples of the more conspicuous organisms were taken for confirmation of identification in the laboratory. At each site, substratum type, geographical orientation, and depth level were recorded. Multivariate analysis (nonmetric multidimensional scaling; analysis of similarity Anosim tests; similarity percentages Simper analysis)...

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