Mostrando recursos 1 - 20 de 330

  1. Alleviation of salt stress using exogenous proline on a citrus cell line

    Lima-Costa, M. E.; Ferreira, S.; Duarte, Amilcar; Ferreira, A. L.
    Salinity constitutes an important abiotic problem since ancient times, world-wide, for it leads to a decrease in productivity of crops with agronomic value. Under salt stress conditions, plant cells develop strategies to cope with Na+ and Cl-, including exclusion and compartmentalisation, induction of antioxidant enzymatic systems and compatible solutes accumulation, such as proline. The precise function of this osmolyte still remains unclear. Proline may act on osmotic adjustment, as a free radical scavenger, protecting enzymes and avoiding DNA damages. It has been also suggested the role of proline in prevention of lipid peroxidation and as a signalling/regulatory molecule. A salt-sensitive...

  2. Diatoms Si uptake capacity drives carbon export in coastal upwelling systems

    Abrantes, Fátima; Cermeno, Pedro; Lopes, Cristina; Romero, Oscar; Matos, Lelia; Van Iperen, Jolanda; Rufino, Marta; Magalhaes, Vitor
    Coastal upwelling systems account for approximately half of global ocean primary production and contribute disproportionately to biologically driven carbon sequestration. Diatoms, silica-precipitating microalgae, constitute the dominant phytoplankton in these productive regions, and their abundance and assemblage composition in the sedimentary record is considered one of the best proxies for primary production. The study of the sedimentary diatom abundance (SDA) and total organic carbon content (TOC) in the five most important coastal upwelling systems of the modern ocean (Iberia-Canary, Benguela, Peru-Humboldt, California, and Somalia-Oman) reveals a global-scale positive relationship between diatom production and organic carbon burial. The analysis of SDA in...

  3. Development of an ecotoxicological protocol for the deep-sea fauna using the hydrothermal vent shrimp Rimicaris exoculata

    Auguste, M.; Mestre, N. C.; Rocha, T. L.; Cardoso, C.; Cueff-Gauchard, V.; Le Bloa, S.; Cambon-Bonavita, M. A.; Shillito, B.; Zbinden, M.; Ravaux, J.; Bebianno, M. J.
    In light of deep-sea mining industry development, particularly interested in massive-sulphide deposits enriched in metals with high commercial value, efforts are increasing to better understand potential environmental impacts to local fauna. The aim of this study was to assess the natural background levels of biomarkers in the hydrothermal vent shrimp Rimicaris exoculata and their responses to copper exposure at in situ pressure (30MPa) as well as the effects of depressurization and pressurization of the high-pressure aquarium IPOCAMP. R. exoculata were collected from the chimney walls of the hydrothermal vent site TAG (Mid Atlantic Ridge) at 3630m depth during the BICOSE...

  4. Coastal storm risk assessment in Europe: examples from 9 study sites

    Ferreira, Óscar; Ciavola, P.; Armaroli, C.; Balouin, Y.; Benavente, J.; Del Río, L.; Deserti, M.; Esteves, L. S.; Furmanczyk, K.; Haerens, P.; Matias, A.; Perini, L.; Taborda, R.; Terefenko, P.; Trifo, E.
    To assess coastal storm risks thi paper compares existing hazards, associated risks, coastal management plans, and civil protection schemes from nine European countries.

  5. Coastal vulnerability assessment based on video wave run-up observations at a mesotidal, steep-sloped beach

    Vousdoukas, Michalis Ioannis; Wziatek, Dagmara; Almeida, Luis Pedro
    Coastal imagery obtained from a coastal video monitoring station installed at Faro Beach, S. Portugal, was combined with topographic data from 40 surveys to generate a total of 456 timestack images. The timestack images were processed in an open-access, freely available graphical user interface (GUI) software, developed to extract and process time series of the cross-shore position of the swash extrema. The generated dataset of 2% wave run-up exceedence values R 2 was used to form empirical formulas, using as input typical hydrodynamic and coastal morphological parameters, generating a best-fit case RMS error of 0.39 m. The R 2 prediction...

  6. Contribution of storms to shoreline changes in mesotidal dissipative beaches: case study in the Gulf of Cadiz (SW Spain)

    Puig, Maria; Del Rio, Laura; Plomaritis, Theocharis A.; Benavente, Javier
    In this study an analysis of storminess and rates of shoreline change is performed and discussed jointly in four geomorphological units of the Gulf of Cadiz (SW Spain) for the period of 1956-2010. For this purpose, storm events are identified based on the following characteristics: wave height above 2.5 m, a minimum duration of 12 h and events with calm periods of less than 24 h were considered as a single event. Subsequently, energy parameters are determined in order to characterize storm-induced impacts. Conversely, geographic information system (GIS) tools are used to measure shoreline changes in aerial photographs and orthophotographs...

  7. Beach erosion and recovery during consecutive storms at a steep-sloping, meso-tidal beach

    Vousdoukas, Michalis I.; Almeida, Luis Pedro M.; Ferreira, Óscar
    This study analyses beach morphological change during six consecutive storms acting on the meso-tidal Faro Beach (south Portugal) between 15 December 2009 and 7 January 2010. Morphological change of the sub-aerial beach profile was monitored through frequent topographic surveys across 11 transects. Measurements of the surf/swash zone dimensions, nearshore bar dynamics, and wave run-up were extracted from time averaged and timestack coastal images, and wave and tidal data were obtained from offshore stations. All the information combined suggests that during consecutive storm events, the antecedent morphological state can initially be the dominant controlling factor of beach response; while the hydrodynamic forcing, and especially the tide and...

  8. RISC-KIT: Resilience-increasing Strategies for Coasts

    Van Dongeren, Ap; Ciavola, Paolo; Martinez, Grit; Viavattene, Christophe; DeKleermaeker, Simone; Ferreira, Óscar; Costa, Cristina; McCall, Robert
    High-impact storm events have demonstrated the vulnerability of coastal zones in Europe and beyond. These impacts are likely to increase due to predicted climate change and ongoing coastal development. In order to reduce impacts, disaster risk reduction (DRR) measures need to be taken, which prevent or mitigate the effects of storm events. To drive the DRR agenda, the UNISDR formulated the Sendai Framework for Action, and the EU has issued the Floods Directive. However, neither is specific about the methods to be used to develop actionable DRR measures in the coastal zone. Therefore, there is a need to develop methods,...

  9. CRAF Phase 1, a framework to identify coastal hotspots to storm impacts

    Ferreira, Óscar; Viavattene, Christophe; Jimenez, Jose; Bole, Annelies; Plomaritis, Theocharis; Costas, Susana; Smets, Steven
    Low-frequency high-impact storms can cause flood and erosion over large coastal areas, which in turn can lead to a significant risk to coastal occupation, producing devastation and immobilising cities and even countries. It is therefore paramount to evaluate risk along the coast at a regional scale through the identification of storm impact hotspots. The Coastal Risk Assessment Framework Phase 1 (CRAF1) is a screening process based on a coastal-index approach that assesses the potential exposure of every kilometre along the coast to previously identified hazards. CRAF1 integrates both hazard (e.g. overwash, erosion) and exposure indicators to create a final Coastal...

  10. Predicting coastal hazards for sandy coasts with a Bayesian Network

    Poelhekke, Laurens; Jager, Wiebke S.; Van Dongeren, Ap; Plomaritis, Theocharis A.; McCall, Robert; Ferreira, Óscar
    Low frequency, high impact storm events can have large impacts on sandy coasts. The physical processes governing these impacts are complex because of the feedback between the hydrodynamics of surges and waves, sediment transport and morphological change. Predicting these coastal changes using a numerical model requires a large amount of computational time, which in the case of an operational prediction for the purpose of Early Warning is not available. For this reason morphodynamic predictions are not commonly included in Early Warning Systems (EWSs). However, omitting these physical processes in an EWS may lead to potential under or over estimation of...

  11. Determination of thresholds for storm impacts

    Ferreira, Óscar; Almeida, L. P.; Rodrigues, B.; Matias, A.
    Storms are responsible for important erosion, coastal retreat and damage when infrastructures are placed within their acting area. The characterisation of storm parameters and associated thresholds for erosion and damage are therefore of fundamental importance for coastal management purposes. This work presents ways of determining thresholds for important morphological changes (including erosion), overwash occurrence and damage associate to storm occurrence. These methods were tested and applied to Ancão Peninsula (South Portugal) and the results shown. The use of these approaches will enable coastal managers to have a quantitative knowledge of consequences associated to each particular storm and to act accordingly, for instance defining set-back lines, designing nourishments or implementing evacuation...

  12. Storm impacts along European coastlines. Part 2: lessons learned from the MICORE project

    Ciavola, Paolo; Ferreira, Óscar; Haerens, Piet; Van Koningsveld, Mark; Armaroli, Clara
    This paper describes the MICORE approach to quantify for nine field sites the crucial storm related physical hazards (hydrodynamic as well as morphodynamic) in support of early warning efforts and emergency response. As a first step historical storms that had a significant morphological impact on a representative number of sensitive European coastal stretches were reviewed and analysed in order to understand storm related morphological changes and how often they occur around Europe. Next, an on-line storm prediction system was set up to enable prediction of storm related hydro- and morphodynamic impacts. The system makes use of existing offthe- shelf models as well as a new open-source morphological model....

  13. Storm impacts along European coastlines. Part 1: The joint effort of the MICORE and ConHaz Projects

    Ciavola, Paolo; Ferreira, Óscar; Haerens, Piet; Van Koningsveld, Mark; Armaroli, Clara; Lequeux, Quentin
    The current paper discusses the topic of marine storm impact along European coastlines, presenting results from two FP7 Projects currently focusing on this topic, one working on the physical aspects of the problem (MICORE) and the other one on the socio-economic implications (ConHaz). The MICORE Project aims to provide on-line predictions of storm-related physical hazards (hydrodynamic as well as morphodynamic). The ConHaz Project addresses the socio-economic implications should these (or other) hazards actually materialize. Together these projects aim to deliver crucial information for emergency response efforts, while realizing the practical limitations for information processing and dissemination during crisis situations. The MICORE Project has developed and demonstrated on-line tools for reliable...

  14. Overwash hazards assessment using a simplified process based approach

    Plomaritis, T. A.; Costas, Susana; Ferreira, Óscar
    Coastal communities are threatened by the impact of severe storms that may cause significant loss or damage of property and life. One of the main processes behind such impacts is the overwash of coastal barriers. In order to estimate the losses associated with a particular event, overwash must be properly parameterized. Here, we propose a novel approach to estimate potential overwash hazards, which includes the associated major processes and crucial parameters. For that purpose it was used the parametrisation of the physical processes developed by Donnelly (2008), and the overwash hazard was related to both flow velocity and flow depth, which are in turn a...

  15. Sense of place, risk perceptions and preparedness of a coastal population at risk (Faro Beach, Portugal): a qualitative content analysis

    Domingues, Rita B.; Costas, Susana; Jesus, Saul Neves de; Ferreira, Óscar
    Faro Beach, a heavily urbanized settlement in Ria Formosa, southern Portugal, is highly vulnerable to coastal hazards, namely beach erosion and overwashes caused by storms, that have resulted in house and road damage on several occasions. Despite the risks, local residents accept to live there. Four semi-structured interviews were conducted to understand residents’ beliefs, risk perceptions and preparedness regarding coastal risks. We used a qualitative content analysis to derive manifest contents from the interviews. Three main themes were identified in the interviews: how residents feel about Faro Beach; how they perceive coastal hazards and risks; and how they deal with those risks. Positive feelings regarding Faro Beach were...

  16. Coastal-flood risk management in central Algarve: vulnerability and flood risk indices (South Portugal)

    Martinez-Grana, A. M.; Boski, T.; Goy, J. L.; Zazo, C.; Dabrio, C. J.
    This paper presents an analysis of the vulnerability (AVI Index) and hazard of flooding by sea level rise (FRI Index) in the central Algarve (South Portugal), between the cities of Portimao and Tavira, which is an area of intense urban impact and fast growing tourism. The vulnerability index was calculated using the following parametric thematic maps: lithology, geomorphology, slopes, elevations, distances, bathymetry, variations of the coastline, wave height and activity, variations of sea level and tidal range. The AVI Index was validated by the results obtained from the analysis of the risk of flooding from the FHI Index applied to...

  17. Morphological response of the saltmarsh habitats of the Guadiana estuary due to flow regulation and sea-level rise

    Sampath, D. M. R.; Boski, T.
    In the context of rapid sea-level rise in the 21st century, the reduction of fluvial sediment supply due to the regulation of river discharge represents a major challenge for the management of estuarine ecosystems. Therefore, the present study aims to assess the cumulative impacts of the reduction of river discharge and projected sea-level rise on the morphological evolution of the Guadiana estuary during the 21st century. The assessment was based on a set of analytical solutions to simplified equations of tidal wave propagation in shallow waters and empirical knowledge of the system. As methods applied to estimate environmental flows do...

  18. Thresholds for storm impacts on an exposed sandy coastal area in southern Portugal

    Almeida, L. P.; Vousdoukas, M. V.; Ferreira, Óscar; Rodrigues, B. A.; Matias, A.
    Storms are one of the most important phenomena responsible for coastal erosion. Their destructive power presents major challenges for coastal management, and knowledge of their characteristics and associated consequences is therefore of paramount importance. In this study, thresholds for storm impacts are defined for a sandy coast in southern Portugal (Faro beach, Ria Formosa) using two different approaches: i) hydrodynamic conditions associated with historical storm impacts (i.e., infrastructural damage); and (ii) computed maximum wave run-up values (RHIGH) compared with beach morphology. Damage thresholds are defined as limits above which the action of a storm exceeds beach front response capability and...

  19. Thresholds for storm impacts on an exposed sandy coastal area in southern Portugal

    Almeida, L. P.; Vousdoukas, M. V.; Ferreira, Óscar; Rodrigues, B. A.; Matias, A.
    Storms are one of the most important phenomena responsible for coastal erosion. Their destructive power presents major challenges for coastal management, and knowledge of their characteristics and associated consequences is therefore of paramount importance. In this study, thresholds for storm impacts are defined for a sandy coast in southern Portugal (Faro beach, Ria Formosa) using two different approaches: i) hydrodynamic conditions associated with historical storm impacts (i.e., infrastructural damage); and (ii) computed maximum wave run-up values (RHIGH) compared with beach morphology. Damage thresholds are defined as limits above which the action of a storm exceeds beach front response capability and...

  20. Historical variation and trends in storminess along the Portuguese South Coast

    Almeida, L. P.; Ferreira, Óscar; Vousdoukas, M. I.; Dodet, G.
    This work investigates historical variation and trends in storm climate for the South Portugal region, using data from wave buoy measurements and from modelling, for the period 1952 to 2009. Several storm parameters (annual number of storms; annual number of days with storms; annual maximum and mean individual storm duration and annual 99.8th percentile of significant wave height) were used to analyse: (1) historical storminess trends; (2) storm parameter variability and relationships; and (3) historical storminess and its relationship to the North Atlantic Oscillation (NAO). No statistically significant linear increase or decrease was found in any of the storm parameters over the period of interest. The main pattern of storm characteristics and...

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