Gari S.R.,UCA |
Gari S.R.,University of Algarve |
Newton A.,University of Algarve |
Icely J.,Sagremarisco Lda |
And 3 more authors.
Marine Policy | Year: 2014
The SAF (Systems Approach Framework) encompasses the ecological, social and economic components of coastal zones and aims to establish a permanent dialogue between scientists, stakeholders and policy makers working within European coastal zones for developing effective ICZM (Integrated Coastal Zone Management). The objective of the present study is to test the application of the SAF for defining eutrophication management options in the Ria Formosa, Portugal. Stakeholders were identified and the issue of eutrophication was agreed upon. Having defined the virtual system, the conceptual model of the Ria Formosa was developed. The formulation of the conceptual model into a mathematical model representing the ecological, social and economic components of the system is then discussed. The linking variable of the three components within the simulation model, as well as the scenarios to be run are then explored. The role of scientists as facilitators within the deliberation process is discussed, and a format by which the final output package could be disseminated is suggested. This case study demonstrates how the SAF could successfully be applied to the management of eutrophication in the Ria Formosa. It also suggests ways in which this approach may be adapted to address unique coastal systems with specific system characteristics. © 2013 Elsevier Ltd.
Zibordi G.,European Commission - Joint Research Center Ispra |
Ruddick K.,Royal Belgian Institute Of Natural Sciences |
Ansko I.,Tartu Observatory |
Moore G.,Bio Optika |
And 3 more authors.
Ocean Science | Year: 2012
Inter-comparison of data products from simultaneous measurements performed with independent systems and methods is a viable approach to assess the consistency of data and additionally to investigate uncertainties. Within such a context the inter-comparison called Assessment of In Situ Radiometric Capabilities for Coastal Water Remote Sensing Applications (ARC) was carried out at the Acqua Alta Oceanographic Tower in the northern Adriatic Sea to explore the accuracy of in situ data products from various in- and above-water optical systems and methods. Measurements were performed under almost ideal conditions, including a stable deployment platform, clear sky, relatively low sun zenith angles and moderately low sea state. Additionally, all optical sensors involved in the experiment were inter-calibrated through absolute radiometric calibration performed with the same standards and methods. Inter-compared data products include spectral waterleaving radiance Lw (λ), above-water downward irradiance Ed(0+,λ) and remote sensing reflectance Rrs(λ). Data products from the various measurement systems/methods were directly compared to those from a single reference system/method. Results for Rrs(λ) indicate spectrally averaged values of relative differences comprised between -1 and +6 %, while spectrally averaged values of absolute differences vary from approximately 6% for the above-water systems/methods to 9% for buoy-based systems/methods. The agreement between Rrs(λ) spectral relative differences and estimates of combined uncertainties of the inter-compared systems/methods is noteworthy. © Author(s) 2012.
Brito A.C.,University of Lisbon |
Brito A.C.,Instituto Nacional Of Recursos Biologicos |
Brito A.C.,Plymouth Marine Laboratory |
Brotas V.,University of Lisbon |
And 9 more authors.
Ecological Indicators | Year: 2012
The Water Framework Directive (WFD) requires the assessment of ecological quality of water bodies based on physico-chemical and biological elements. This paper is focused on the use of phytoplankton as a biological indicator of ecological quality in Portuguese transitional waters (TWs). Phytoplankton is considered to be a sensitive indicator to environmental changes, especially nutrient enrichment, and is therefore useful for evaluating eutrophication processes. According to the WFD, three metrics should be generally considered to assess ecological status: phytoplankton biomass (chlorophyll a), phytoplankton composition and abundance, and phytoplankton bloom intensity and frequency. This work presents an integrated methodology that comprises the first and the last metrics indicated above, analyzed during the growing season (February-October). Significant (p < 0.01) direct relationships between pressures (nutrient concentrations) and the biomass metric (90th percentile of chlorophyll a) were found, which allow confidence in the assessment. Afterwards, reference conditions and the boundaries of a five-class classification were set using phytoplankton biomass. These boundaries were further tested against the results of a risk assessment, carried out on the basis of primary (e.g. high chlorophyll concentrations) and secondary symptoms (e.g. oxygen depletion) of eutrophication, as well as nutrient loads and the susceptibility of systems. Significant (p < 0.01) direct relationships were also found between biomass and the scale of risk. Phytoplankton bloom intensity and frequency data were also used in the analysis although data were too scarce for a detailed evaluation of all water bodies (WBs). The worst ecological status (moderate to poor) were found in only few water bodies in the Ria de Aveiro, Mondego, Sado and Guadiana estuaries. Further research is needed for testing and improving the tool, especially for the phytoplankton bloom intensity and frequency metric. © 2011 Elsevier Ltd. All rights reserved.
Goela P.C.,University of Algarve |
Goela P.C.,University of Cádiz |
Cordeiro C.,University of Algarve |
Cordeiro C.,University of Lisbon |
And 7 more authors.
Journal of Marine Systems | Year: 2016
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 (Qx) and southerly (Qy) Ekman transport components.In the first part of the study, time series were inspected for trend and seasonality over the whole period. The seasonally adjusted time series revealed an increasing slope for SST (0.15 °C per decade) and decreasing slopes for Qx (-84.01 m3 s-1 km-1 per decade) and Qy (-25.20 m3 s-1 km-1 per decade), over the time horizon. Structural breaks analysis applied to the time series showed that a statistically significant incremental increase in SST was more pronounced during the last decade.Cross-correlation between upwelling indices and SST revealed a time delay of 5 and 2 days between Qx and SST, and between Qy and SST, respectively. A spectral analysis combined with the previous analysis enabled the identification of four oceanographic seasons. Those seasons were later recognised over a restricted time period of 4 years, between 2008 and 2012, when there was an extensive sampling programme for the validation of ocean colour remote sensing imagery. The seasons were defined as: summer, with intense and regular events of upwelling; autumn, indicating relaxation of upwelling conditions; and spring and winter, showing high interannual variability in terms of number and intensity of upwelling events. © 2016 The Authors.
Thaman B.,University of Algarve |
Icely J.D.,University of Algarve |
Icely J.D.,Sagremarisco Lda. |
Fragoso B.D.D.,University of Algarve |
And 2 more authors.
Ocean and Coastal Management | Year: 2016
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, information obtained about community involvement in conservation activities in the two study areas was compared. Results showed that while community members showed high levels of involvement in all conservation activities in the Fiji study (88%), this was not the case in the Portugal study (43%), where results showed that lack of community involvement, leading to ineffective conservation. In both cases, however, the levels of involvement appear to have influenced community perceptions of conservation efforts' impact upon livelihoods. The Fiji study showed that community-focused conservation can be successful given appropriate community involvement. This contrasted with the Portugal study where conservation efforts were not community-focused and often led to conflicts and criticisms. A bottom-up approach has been utilized in Yadua, Fiji, whereas a top-down approach is clearly observed for the PNSACV in Portugal. A more holistic approach to conservation would empower local communities and ensure the successful implementation of conservation programmes. © 2016 Elsevier Ltd
Weissbach A.,Linnaeus University |
Rudstrom M.,Linnaeus University |
Olofsson M.,Linnaeus University |
Bechemin C.,French Research Institute for Exploitation of the Sea |
And 6 more authors.
Limnology and Oceanography | Year: 2011
This study investigates the effect of filtrates from an allelopathic dinoflagellate, Alexandrium tamarense, on four microbial food webs that have been manipulated experimentally from natural seawater by modifying the availability of resources in the form of dissolved organic carbon with additions of peptone, and by altering the grazing pressure with size fractionation. Bacterial production was generally not affected by allelochemicals, but bacteria showed higher net growth in all food webs when allelochemicals were added, whereas heterotrophic nanoflagellates > 7 μm and ciliates were constrained in all food webs. Allelochemicals had the largest negative effects on microbial communities with low grazing pressure. In food webs with high grazing pressure and additional resources, phytoplankton and small nanoflagellates were positively affected by the addition of allelochemicals, suggesting that those were interfering with trophic interactions in the microbial communities. By the lysis of organisms sensitive towards allelochemicals, resources are made available and grazing pressure on certain microorganisms is reduced. However, the intensity of these interactions is modulated by both the availability of resources and the biomass of grazers in the initial food web. © 2011, by the American Society of Limnology and Oceanography, Inc.
Brito A.C.,Napier University |
Brito A.C.,University of Algarve |
Newton A.,University of Algarve |
Tett P.,Napier University |
And 2 more authors.
Journal of Experimental Marine Biology and Ecology | Year: 2010
The yield of phytoplankton chlorophyll from nitrogen is a useful parameter in the study of eutrophication of coastal waters, providing the link between chlorophyll formation and nutrient consumption. This parameter has been estimated for microphytobenthos from Ria Formosa lagoon on the south coast of Portugal with a series of three experiments conducted in May and September 2007. Six sediment cores were collected from Ria Formosa in acrylic cylinders and cork stoppers were placed in the bottom. Water samples were collected in large containers and prepared (filtered and enriched) to be pumped to the top of the sediment inside the acrylic cylinders, which are the microcosms of the experiments. Microcosms were isolated to avoid water exchanges and placed in large tanks full of water to maintain temperature stability. Experiments were run for 5 to 9 days in a continuous diluted nutrient enriched system. One of the experiments was carried out with half the microcosms in the dark to evaluate the nutrient fluxes between the sediment and the water column, when no algal growth is expected. Nutrient fluxes of muddy sediments, during the two last days of the experiment in the dark were estimated to be 0.1015 μmol cm- 2 d- 1 for nitrogen, - 0.0015 μmol cm- 2 d- 1 for phosphorus, and 0.1395 μmol cm- 2 d- 1 for silicon. The yield of chlorophyll was determined to be between 3.65 and 4.11 μg chl (μmol N)- 1 from nitrogen and between 4.03 and 4.77 μg chl (μmol Si)- 1 for silicon in muddy sediments. It was not possible to determine the yield from phosphorus. These values are higher than for phytoplankton which may be due to physiological reasons, or due to the presence of a smaller fraction of microheterotrophs, which would divert nutrients. For sand, smaller yields were obtained but it is likely that this was mainly due to the fact that the values of the sediment fluxes used were the ones obtained for mud, which are higher than they should be for sand. This extra input of nutrients is considered to be taken up by algae, thereby decreasing the value of the yield. Therefore, reliable chlorophyll yield estimates for sand could not be obtained. © 2009 Elsevier B.V. All rights reserved.
Cristina S.,University of Algarve |
Cristina S.,University of Cádiz |
Icely J.,University of Algarve |
Icely J.,Sagremarisco Lda |
And 4 more authors.
Continental Shelf Research | Year: 2015
The exclusive economic zones (EEZ) of coastal countries are coming under increasing pressure from various economic sectors such as fishing, aquaculture, shipping and energy production. In Europe, there is a policy to expand the maritime economic sector without damaging the environment by ensuring that these activities comply with legally binding Directives, such as the Marine Strategy Framework Directive (MSFD). However, monitoring an extensive maritime area is a logistical and economic challenge. Remote sensing is considered one of the most cost effective methods for providing the spatial and temporal environmental data that will be necessary for the effective implementation of the MSFD. However, there is still a concern about the uncertainties associated with remote sensed products. This study has tested how a specific satellite product can contribute to the monitoring of a MSFD Descriptor for "good environmental status" (GES). The results show that the quality of the remote sensing product Algal Pigment Index 1 (API 1) from the MEdium Resolution Imaging Spectrometer (MERIS) sensor of the European Space Agency for ocean colour products can be effectively validated with in situ data from three stations off the SW Iberian Peninsula. The validation results show good agreement between the MERIS API 1 and the in situ data for the two more offshore stations, with a higher coefficient of determination (R2) of 0.79, and with lower uncertainties for the average relative percentage difference (RPD) of 24.6% and 27.9% and a root mean square error (RMSE) of 0.40 and 0.38 for Stations B and C, respectively. Near to the coast, Station A has the lowest R2 of 0.63 and the highest uncertainties with an RPD of 112.9% and a RMSE of 1.00. It is also the station most affected by adjacency effects from the land: when the Improved Contrast between Ocean and Land processor (ICOL) is applied the R2 increases to 0.77 and there is a 30% reduction in the uncertainties estimated by RPD. The MERIS API 1 product decreases from inshore to offshore, with higher values occurring mainly between early spring and the end of the summer, and with lower values during winter. By using the satellite images for API 1, it is possible to detect and track the development of algal blooms in coastal and marine waters, demonstrating the usefulness of remote sensing for supporting the implementation of the MSFD with respect to Descriptor 5: Eutrophication. It is probable that remote sensing will also prove to be useful for monitoring other Descriptors of the MSFD. © 2015 The Authors.
Cristina S.C.V.,University of Algarve |
Cristina S.C.V.,University of Cádiz |
Moore G.F.,Bio Optika |
Goela P.R.F.C.,University of Algarve |
And 4 more authors.
International Journal of Remote Sensing | Year: 2014
Water-leaving reflectance (ρw) data from the European Space Agency ocean colour sensor Medium Resolution Imaging Spectrometer (MERIS) was validated with in situ ρw between October 2008 and November 2011, off Sagres on the southwest coast of the Iberian Peninsula. The study area is exceptional, since Stations A, B, and C at 2, 10, and 18 km offshore are in optically deep waters at approximately 40, 100, and 160 m, respectively. These stations showed consistently similar bio-optical properties, characteristic of Case 1 waters, enabling the evaluation of adjacency effects independent of the usual co-varying inputs of coastal waters. Using the third reprocessing of MERIS with the standard MEGS 8.1 processor, four different combinations of procedures were tested to improve the calibration between MERIS products and in situ data. These combinations included no vicarious adjustment (NoVIC), vicarious adjustment (VIC), and, for mitigating the effects of land adjacency on MERIS ρw, the improved contrast between ocean and land (ICOL) processor (version 2.7.4) and VIC + ICOL. Out of approximately 130 potential matchups for each station, 38-77%, 74-86%, and 88-90% were achieved at Stations A, B, and C, respectively, depending on which of the four combinations were used. Analyses of ρw comparing these various procedures, including statistics, scatter plots, histograms, and MERIS full-resolution images, showed that the VIC procedure compared with NoVIC produced minimal changes to the calibration. For example, at the oceanic Station C, the regression slope was closer to unity at all wavelengths with NoVIC compared to VIC, whereas, with the exception of wavelengths 412 and 443 nm, the intercept, mean ratio (MR), absolute percentage difference (APD), and relative percentage difference (RPD) were better with NoVIC. The differences for MR and APD indicate that there was marginal improvement for these two bands with VIC, and an over-adjustment with RPD. ICOL also showed inconsistent results for improving the retrieval of the near-shore conditions, but under some conditions, such as ρw at wavelength 560 nm, the improvement was striking. VIC + ICOL showed results intermediate between those of VIC and ICOL implemented separately. In relation to other validation sites, the offshore Station C at Sagres had much in common with the Mediterranean deep water, BOUSSOLE buoy, although the matchup statistics between MERIS ρw and in situ ρw were much better for Sagres than for BOUSSOLE. Strikingly, the matchup statistics for ρw at Sagres were very similar to those for the Acqua Alta Oceanographic Tower (AAOT), where the AAOT showed more scatter at 412 nm, probably because of the atmospheric correction where the aerosol optical thickness is higher at the AAOT. Conversely, Sagres showed much greater scatter at 665 nm in the red as the values were generally close to the limits of detection owing to the clearer waters at Sagres compared to the more turbid waters at the AAOT. © 2014 © 2014 The Author(s). Published by Taylor & Francis.
Costa Goela P.,University of Algarve |
Costa Goela P.,Sagremarisco Lda. |
Icely J.,University of Algarve |
Icely J.,Sagremarisco Lda. |
And 5 more authors.
Continental Shelf Research | Year: 2013
The variability in coefficients of absorption for phytoplankton was assessed for an area off the Southwest coast of Portugal. This area included three sites at 2, 10 and 18km perpendicular to the coast, sampled at surface, mid-Secchi and Secchi depths at each site. Phytoplankton absorption coefficients were transformed into specific coefficients (a* ph(λ)) by normalizing them with respect to chlorophyll a (Chla) concentrations determined by High Performance Liquid Chromatography. The influence on the variability of the absorption coefficient of phytoplankton was assessed for physico-chemical and biological parameters such as nutrients or Chla levels, as well as size structure and abundance of the phytoplankton community. The results showed that the phytoplankton absorption coefficients decreased from inshore to offshore, but were relatively constant within the water column, revealing a well-mixed column. The a* ph(λ) varied inversely with Chla content, with minima in Autumn and Spring, matching phytoplankton blooms. The effects of the size structure of the community and pigment composition on the variability of phytoplankton absorption coefficient were studied and results showed that size structure had a greater influence on the variability of the phytoplankton absorption, although the pigment contribution was also important. © 2012 Elsevier Ltd.