Mostrando recursos 1 - 20 de 241

  1. The effect of density in larval rearing of the pullet carpet shell Venerupis corrugata (Gmelin, 1791) in a recirculating aquaculture system

    Joaquim, Sandra; Matias, Domitília; Matias, Ana Margarete; Leitão, Alexandra; Soares, Florbela; Cabral, Marina; Chícharo, Luís; Gaspar, Miguel B.
    The pullet carpet shell Venerupis corrugata is an economically valuable species in several European countries, however, nowadays stocks are under high fishing pressure. Hatchery production of juveniles for release is a major contributor to strengthen the stock and consequently improve the sustainability of the natural stocks. This study aimed to determine the feasibility of rearing V. corrugata larvae with different larval densities (10, 40 and 200 larvae per mL) in a recirculating aquaculture system (RAS), compared with the traditional larval rearing methodology (Batch). The mean survival, growth and metamorphic rate of V. corrugata larvae in RAS was higher (11.1%; 71.3m;...

  2. Growth kinetics and physiological behavior of co-cultures of Saccharomyces cerevisiae and Kluyveromyces lactis, fermenting carob sugars extracted with whey

    Rodrigues, B.; Lima-Costa, Maria Emília; Constantino, A.; Raposo, S.; Felizardo, C.; Gonçalves, D.; Fernandes, T.; Dionísio, L.; Peinado, J. M.
    Alcoholic fermentation of carob waste sugars (sucrose, glucose and fructose) extracted with cheese whey, by co-cultures of Saccharomyces.cerevisiae and Kluyveromyces lactis has been analyzed. Growth and fermentation of S. cerevisiae in the carob-whey medium showed an inhibition of about 30% in comparison with water-extracted carob. The inhibition of K. lactis on carob-whey was greater (70%) when compared with the whey medium alone, due to osmolarity problems. Oxygen availability was a very important factor for K. lactis, influencing its fermentation performance. When K. lactis was grown alone on carob-whey medium, lactose was always consumed first, and glucose and fructose were consumed...

  3. Time series analysis of data for sea surface temperature and upwelling components from the southwest coast of Portugal

    Costa Goela, Priscila; Cordeiro, Clara; Danchenko, Sergei; Icely, John; Cristina, Sónia; Newton, Alice
    This study relates sea surface temperature (SST) to the upwelling conditions off the southwest coast of Portugal using statistical analyses of publically available data. Optimum Interpolation (OI) of daily SST data were extracted from the United States (US) National Oceanic and Atmospheric Administration (NOAA) and data for wind speed and direction were from the US National Climatic Data Center. Time series were extracted at a daily frequency for a time horizon of 26 years. Upwelling indices were estimated using westerly (Q(x)) and southerly (Q(y)) Ekman transport components.In the first part of the study, time series were inspected for trend and...

  4. An assessment of urban vulnerability in the Amazon Delta and Estuary: a multi-criterion index of flood exposure, socio-economic conditions and infrastructure

    Mansur, Andressa V.; Brondizio, Eduardo S.; Roy, Samapriya; Hetrick, Scott; Vogt, Nathan D.; Newton, Alice
    The Amazon Delta and Estuary (ADE) is a region of continental and global ecological importance. Controversy, many of the basic infrastructure and services essential for quality of life and sustainable development of this delta are absent. Using a conceptual model to define socio-economic vulnerability in the urban ADE, a thorough assessment of indicators including sanitation services, housing conditions, household income, population, flood risk and unplanned settlements was conducted in 41 cities at the census sector scale (n = 2938). A multi criterion index was applied to classify urban vulnerability from three dimensions: flood exposure, socio-economic sensitivity and infrastructure. This is...

  5. Relationships between broodstock condition, oocyte quality, and 24h D-larval survival during the spawning season of the pullet carpet shell Venerupis corrugata (Gmelin, 1791)

    Joaquim, Sandra; Matias, Domitília; Matias, Ana Margarete; Gonçalves, Rui; Vera, Cátia; Chícharo, Luís; Gaspar, Miguel B.
    Venerupis corrugata is commercially exploited in Europe. Over-fishing and recruitment failure is causing the decline of its populations and stock sustainability. Knowledge of this species reproduction is paramount to establish hatchery production of juveniles for restoring natural beds. This work aimed to find a relationship between broodstock condition, oocyte quality, and viability of 24h D-larvae. Adult specimens were induced to spawn by thermal stimulation. From each female, oocytes were taken for biochemical analyses (proteins, total lipids, and carbohydrates), and the remaining oocytes were fertilized. The 24h D-larval yield was calculated after embryo incubation. Spawning in the hatchery with 'wild' broodstock...

  6. Larval hatching and development of the wedge shell (Donax trunculus L.) under increased CO2 in southern Portugal

    Pereira, Alexandre Miguel; Range, Pedro; Campoy, Ana; Oliveira, Ana Paula; Joaquim, Sandra; Matias, Domitília; Chícharo, Luís; Gaspar, Miguel Baptista
    Noticeable changes in global temperatures, climate and ocean carbon chemistry are the result of carbon dioxide increase in the atmosphere. This increase has been mitigated by the oceans capacity to absorb one-fourth of the carbon dioxide in the atmosphere, although this CO2 intake affects oceans carbonate chemistry [i.e., ocean acidification-(OA)]. The detrimental effect of OA in the development and shell formation has been studied in several species of bivalves, although no information is available on the wedge shell Donax trunculus, a gastronomically appreciated species and an important economical resource in several southern European countries. We evaluated the effect of pCO(2)...

  7. Catalyzing action towards the sustainability of deltas

    Brondizio, Eduardo S.; Foufoula-Georgiou, Efi; Szabo, Sylvia; Vogt, Nathan; Sebesvari, Zita; Renaud, Fabrice G.; Newton, Alice; Anthony, Edward; Mansur, Andressa V.; Matthews, Zoe; Hetrick, Scott; Costa, Sandra M.; Tessler, Zachary; Tejedor, Alejandro; Longjas, Anthony; Dearing, John A.
    Deltaic systems are among the most dynamic and productive environments on Earth and many have a high population density. Deltas play a central role in food and water security but are increasingly facing hazards such as submergence, riverine and coastal flooding, and coastal erosion. This paper synthesizes efforts of the Belmont Forum Deltas project, an international network of interdisciplinary research collaboration with focal areas in the Mekong, the Ganges Brahmaputra, and the Amazon deltas. The inherent complexity and dearth of knowledge about deltas require disciplinary expertise to advance jointly with interdisciplinary collaboration. An overarching research framework articulates focal research areas...

  8. Wave runup and overwash on a prototype-scale sand barrier

    Blenkinsopp, C. E.; Matias, Ana; Howe, D.; Castelle, B.; Marieu, V.; Turner, I. L.
    Accurate methods to predict wave runup are of critical importance to coastal engineers. Extreme runup during storm conditions can present a danger to coastal infrastructure and lead to dune overtopping and erosion, overwash. of barrier beaches and is an essential design parameter for certain coastal protection works. This paper uses data obtained during the unique BARDEX II prototype-scale laboratory experiment on a reflective sand barrier to investigate wave runup and overwash. Runup measurements were acquired using ultrasonic altimeters, 2D scanning Lidar and camera systems under controlled wave and water level conditions. It was found that extreme runup (R-2%) scaled well...

  9. IT-OSRA: applying ensemble simulations to estimate the oil spill risk associated to operational and accidental oil spills

    Neves, Antonio Augusto Sepp; Pinardi, Nadia; Martins, Flávio Augusto Bastos da Cruz
    Oil Spill Risk Assessments (OSRAs) are widely employed to support decision making regarding oil spill risks. This article adapts the ISO-compliant OSRA framework developed by Sepp Neves et al. (J Environ Manag 159:158-168, 2015) to estimate risks in a complex scenario where uncertainties related to the meteo-oceanographic conditions, where and how a spill could happen exist and the risk computation methodology is not yet well established (ensemble oil spill modeling). The improved method was applied to the Algarve coast, Portugal. Over 50,000 simulations were performed in 2 ensemble experiments to estimate the risks due to operational and accidental spill scenarios...

  10. A comparison of rural community perceptions and involvement in conservation between the Fiji Islands and Southwestern Portugal

    Thaman, Baravi; Icely, John D.; Fragoso, Bruno D. D.; Veitayaki, Joeli
    Community involvement in conservation provides significant benefits including the ownership of resources and initiatives that integrate traditional and local knowledge into decision-making processes and management activities. This study assesses and compares the effectiveness of community involvement in conservation initiatives in two different countries, by examining the community's level of involvement and their perceptions of conservation in Yadua (Fiji) and the Natural Park of Southwest Alentejo and Costa Vicentina (PNSACV) (Portugal). The hypothesis was that "Effective community involvement contributes to the success, ownership, benefits, positive impacts and sustainability of conservation projects". Using questionnaires, structured interviews and document analyses of past literature,...

  11. New species in aquaculture: are the striped venus clam Chamelea gallina (Linnaeus, 1758) and the surf clam Spisula solida (Linnaeus 1758) potential candidates for diversification in shellfish aquaculture?

    Joaquim, Sandra; Matias, Domitilia; Matias, Ana Margarete; Gonçalves, Rui; Chícharo, Luis; Gaspar, Miguel B.
    The surf Spisula solida and the striped venus Chamelea gallina clams support important fisheries in Europe. These fisheries have been affected by inter-annual fluctuations in stock abundance and recruitment failures. Aquaculture could contribute to address these problems through the production of larvae or juveniles for stock-enhancement programmes. In the present study, the prerequisites to produce these species in hatchery were established. Of the different methods used to obtain gametes (thermal stimulation, scarification and flow through), C. gallina spawned in the flow through only. By its turn, the best method for obtaining gametes for S. solida was stripping. Higher survivals of...

  12. The transatlantic introduction of weakfish Cynoscion regalis (Bloch & Schneider, 1801) (Sciaenidae, Pisces) into Europe

    Morais, Pedro; Teodósio, Maria A.
    Weakfish Cynoscion regalis (Bloch and Schneider, 1801) is a sciaenid fish native to the east coast of North America and has been recently collected in three areas of the Iberian Peninsula (Europe). We aimed to i) provide the first report of the presence of weakfish in Europe, ii) hypothesize the most likely introduction vector, iii) discuss the potential for ecological overlap between weakfish and meagre Argyrosomus regius (Asso, 1801), the native Sciaenidae species, and iv) highlight the importance of citizen science in the detection of nonnative species. Weakfish were captured in the Sado estuary (July 2014), Gulf of Cadiz (November 2015) and the adjacent...

  13. Habitat-specific benthic metabolism in a Mediterranean-type intermittent stream

    Sroczynska, Katarzyna; Claro, Marilia; Range, Pedro; Wasiak, Katarzyna; Wojtal-Frankiewicz, Adrianna; Ben-Hamadou, Radhouan; Leitão, Francisco; Chícharo, Luís
    A modified flow-through chamber method was used to measure gross primary production (GPP), net primary production (NPP), community respiration (CR) and associated environmental variables in an intermittent Mediterranean-type stream in Southern Portugal. Three common types of in stream habitats were targeted: cobble (C), cobble covered with filamentous algae (C+A) and leaf litter (LL). NPP, GPP and CR differed significantly among all three habitats. GPP increased with chlorophyll a and, less strongly, with photosynthetic active radiation and, therefore, was highest in C+A habitat. The highest CR was in LL and its variation was best determined by ash-free dry mass (AFDM) of...

  14. Evolution of a relocated inlet migrating naturally along an open coast

    Popesso, Chiara; Pacheco, Andre; Ferreira, Óscar; Fontolan, Giorgio
    Ancao Inlet is a small migrating inlet that was relocated in 1997 and has been monitored since then. In October 2015, it was about to conclude its third eastward migrating cycle since the 1940s. Morphological parameters and migration rates were correlated with oceanographic settings to evaluate the importance of different mechanisms in the evolutionary phases of the inlet. The migration trend is related to the dominant southwest sea conditions, inducing the alongshore sediment transport from west to east. The inherited features of the downdrift side area were also considered as rate of migration constraints. In this paper, we show how...

  15. Hydrodynamic changes imposed by tidal energy converters on extracting energy on a real case scenario

    Pacheco, A.; Ferreira, Óscar
    The development on tidal turbine technology is ongoing with focus on several aspects, including hydrodynamics, operation and environment. Before considering an area for exploitation, tidal energy resource assessments in pre-feasibility energy extraction areas must include the relevant characteristics of the device to be used. The present paper uses the momentum source approach to represent a floatable tidal energy converter (TECs) in a coastal hydro-morphodynamic model and to perform model simulations utilising different TEC array schernes by quantifying the aggregated drag coefficient of the device array. Simulations for one-month periods with nested models were performed to evaluate the hydrodynamic impacts of...

  16. Using an integrated approach to assess the sediment quality of an estuary from the semi-arid coast of Brazil

    Souza, Ivanildo Surini; Araujo, Giuliana Seraphim; Cruz, Ana Carolina Feitosa; Fonseca, Taina Garcia; Camargo, Julia Beatriz Duarte Alves; Medeiros, Guilherme Fulgencio; Abessa, Denis M. S.
    The Jundiai-Potengi Estuary (JPE) on the semi-arid coast of Brazil is influenced by multiple sources of pollution. Sediment quality at 10 JPE sites was evaluated through an integrated approach. Rainy and dry seasons were considered. Collected sediments were analyzed for texture, metal, nitrogen, phosphorus concentrations, and toxicity to invertebrates. Geochemical and ecotoxicological data were integrated using qualitative approaches and multivariate techniques. We observed decreased sediment quality in both seasons, particularly in the mid estuary. In the dry season, the contamination-toxicity relationship was clearer, as hydrological conditions favor contaminant retention within the estuary. Rainy season conditions were found to be worse,...

  17. MERIS phytoplankton time series products from the SW Iberian Peninsula (Sagres) using seasonal-trend decomposition based on loess

    Cristina, Sónia; Cordeiro, Clara; Lavender, Samantha; Goela, Priscila; Icely, John; Newton, Alice
    The European Space Agency has acquired 10 years of data on the temporal and spatial distribution of phytoplankton biomass from the MEdium Resolution Imaging Spectrometer (MERIS) sensor for ocean color. The phytoplankton biomass was estimated with the MERIS product Algal Pigment Index 1 (API 1). Seasonal-Trend decomposition of time series based on Loess (STL) identified the temporal variability of the dynamical features in the MERIS products for water leaving reflectance ((w)()) and API 1. The advantages of STL is that it can identify seasonal components changing over time, it is responsive to nonlinear trends, and it is robust in the...

  18. Effects of light polarization and waves slope statistics on the reflectance factor of the sea surface

    D'Alimonte, Davide; Kajiyama, Tamito
    Above-water radiometry depends on estimates of the reflectance factor rho of the sea surface to compute the in situ water-leaving radiance. The Monte Carlo code for ocean color simulations MOX is used in this study to analyze the effect of different environmental components on r values. A first aspect is examining the reflectance factor without and by accounting for the sky-radiance polarization. The influence of the sea-surface statistics at discrete grid points is then considered by presenting a new scheme to define the variance of the waves slope. Results at different sun elevations and sensor orientations indicate that the light...

  19. Technical note: Algal Pigment Index 2 in the Atlantic off the southwest Iberian Peninsula: standard and regional algorithms

    Goela, Priscila; Cristina, Sonia; Kajiyama, Tamito; Icely, John; Moore, Gerald; Fragoso, Bruno; Newton, Alice
    In this study, Algal Pigment Index 2 (API2) is investigated in Sagres, an area located in the Atlantic off the southwestern Iberian Peninsula. Standard results provided by the MEdium Resolution Image Spectrometer (MERIS) ocean colour sensor were compared with alternative data products, determined through a regional inversion scheme, using both MERIS and in situ remote sensing reflectances (R-rs) as input data. The reference quantity for performance assessment is in situ total chlorophyll a (TChl a) concentration estimated through a phytoplankton absorption coefficient (i.e. equivalent to API2). Additional comparison of data products has also been addressed for TChl a concentration determined...

  20. International Centre for Coastal Ecohydrology: applying the ecohydrology approach for the sustainable functioning of coastal ecosystems

    Chícharo, L.; Ben-Hamadou, R.; Amaral, A.; Range, Pedro; Mateus, C.; Piló, D.; Marques, R.; Morais, P.; Chícharo, M. A.
    Coastal areas are among the most sensitive and productive ecosystems around the world, providing for the subsistence of large numbers of people, particularly in developing countries. Human pressure on coastal areas has dramatically increased during the last decades and climate changes will pose new threats to these areas, as expected from sea-level rise and the decrease in freshwater discharges from rivers (Chicharo et al., 2009). The International Centre for Coastal Ecohydrology (ICCE) a newly approved centre under the auspices of UNESCO, in October 2009, is located in the Algarve region (south Portugal). The centre acts as a facilitator and synergetic structure by providing the articulation...

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