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Abstract The opening of the Cacela Inlet (southern Portugal) in 2010 led to unforeseen effects observed after 2017, including an extreme acceleration of the retreat of the inland lagoon margin from about 0.2 to 2 m/year. This was a consequence of the development of a large flood delta in an area of limited accommodation space, forcing the main tidal channel to move inland. The coastal retreat currently affects a flat sandy area that separates the old and inactive Cacela cliff from the lagoon. Between 2035 and 2040, the currently inactive Cacela cliff is likely to become active again, posing a potential risk of damage to a medieval fortress and the existing settlement of Cacela Velha, an unforeseen cascading effect of the opening of the inlet. In order to prevent instability and damage to this legally protected area of national and public interest, several coastal management measures will be required.

The opening of the Cacela Inlet (southern Portugal) in 2010 led to unforeseen effects observed after 2017, including an extreme acceleration of the retreat of the inland lagoon margin from about 0.2 to 2 m/year. This was a consequence of the development of a large flood delta in an area of limited accommodation space, forcing the main tidal channel to move inland. The coastal retreat currently affects a flat sandy area that separates the old and inactive Cacela cliff from the lagoon. Between 2025 and 2030, the currently inactive Cacela cliff is likely to become active again, posing a potential risk of damage to a medieval fortress and the existing settlement of Cacela Velha, an unforeseen cascading effect of the opening of the inlet. In order to prevent instability and damage to this legally protected area of national and public interest, several coastal management measures will be required. [ABSTRACT FROM AUTHOR]

Phytoplankton are dominant primary producers and key indicators in aquatic ecosystems. Understanding the controlling factors on the structure of phytoplankton assemblages is fundamental, but particularly challenging at the land–ocean interface. To identify the patterns and predictors of phytoplankton assemblage structure in the Ria Formosa coastal lagoon (south Portugal), this study combined phytoplankton abundance along a transect between the discharge point of a wastewater treatment plant and a lagoon inlet, over two years, with physico-chemical, hydrographic, and meteo-oceanographic variables. Our study identified 147 operational taxonomic units (OTUs), and planktonic diatoms (60–74%) and cryptophyceans (17–25%) dominated the phytoplankton in terms of abundance. Despite strong lagoon hydrodynamics, and the lack of spatial differences in the phytoplankton abundance and most diversity metrics, the multivariate analysis revealed differences in the assemblage structure between stations (p < 0.001) and seasons (p < 0.01). Indicator analysis identified cryptophyceans as lagoon generalists, and 11 station-specific specialist OTUs, including Kryptoperidinium foliaceum and Oscillatoriales (innermost stations) and potentially toxigenic species (Pseudo-nitzschia and Dinophysis; outer lagoon station, p < 0.05). Water temperature, pH, and nutrients emerged as the variables that best explained the changes in the phytoplankton assemblage structure (p < 0.001). Our findings provide insight into the relevance of local anthropogenic and natural forcings on the phytoplankton assemblage structure and can be used to support the management of RF and other coastal lagoons. [ABSTRACT FROM AUTHOR]

Aim: Assessment of the fate of microbial contamination driven from treated wastewater disposal at a highly productive zone on a South European coastal lagoon (Ria Formosa). Methods and results: Microbial indicators of contamination (Total coliforms, Escherichia coli, and Enterococci) were evaluated monthly during September 2018–September 2020 at three study areas (Faro, Olhão, and Tavira) under different wastewater discharge flows and hydrodynamic conditions. Additional data on E. coli monitoring in bivalves, available from the national institution responsible for their surveillance was also considered. The maximum microbial contamination was found at Faro, the highest-load and less-flushed study area, contrasting the lowest contamination at Olhão, a lower-load and strongly flushed area. The wastewater impact decreased along the spatial dispersal gradients and during high water, particularly at Faro and Tavira study areas, due to a considerable dilution effect. Microbial contamination at Olhão increased during the summer, while at the other study areas seasonal evidence was not clear. Data also indicate that E. coli in bivalves from bivalve production zones next to the three study areas reflected the differentiated impact of the wastewater treatment plants effluents on the water quality of those areas. Conclusions: Effluent loads together with local hydrodynamics, water temperature, solar radiation, precipitation, and land runoff as well as seabirds populations and environmentally adapted faecal or renaturelized bacterial communities, contributed to microbial contamination of the study areas. [ABSTRACT FROM AUTHOR]

The establishment of large populations of yellow-legged gull Larus michahellis in coastal and urban areas can lead to strong changes in vegetation cover and composition through creating physical disturbance in the vegetation and impacting the soil quality through defecation. In this study, we evaluated the effects of breeding yellow-legged gull populations on tall and short vegetation cover and plant species composition in old (occupied for 13 years) and new (occupied for 3 years) colony sites in grey dunes of the Algarve, southern Portugal. In each site, sampling plots were used to measure the percentage of vegetation cover in areas with and without breeding gulls. In the old colony site, the cover by tall vegetation was substantially reduced and the cover by short vegetation substantially increased in the areas where gulls are breeding in comparison with the adjacent areas. In the new colony sites, there were only minor differences. The increase in cover of short vegetation in the breeding area of the old colony site was mostly by nitrophilous species (Paronychia argentea and Malcolmia littorea) and should be explained by the decrease in vegetation cover of tall plant species and by feces deposition. Tall and slow-growing species Suaeda maritima and Helichrysum italicum covers were negatively affected. Our results showed that yellow-legged gulls affected vegetation cover and composition of grey dunes after 3 years of consecutive breeding, and this should be considered in the management of these habitats where breeding yellow-legged gulls are increasing. [ABSTRACT FROM AUTHOR]

Coastal lagoons are highly productive systems and the quantification of mass fluxes, which is of paramount importance for the sustainable management of these systems, remains poorly studied. In this context, a detailed study was conducted to better understand the exchanges between the productive coastal lagoon Ria Formosa (South-West Europe) and the ocean. The exchanges of water, nutrients, chlorophyll-a and suspended solids between the main inlets (Faro-Olhão inlet - BFO; Armona inlet - BAR; and Ancão inlet - BAN) and adjacent channels (Faro - CF and Olhão - CO) and the adjacent ocean were estimated along complete semidiurnal tidal cycles, under extreme fortnightly tidal ranges and different seasonal and environmental/oceanographic conditions. The net tidal prism was highest during spring tides. Among the three inlets, BFO was the most important in terms of exchange, followed by BAR and BAN. Net transport at BFO was lowest during the Summer campaign, although it exported material that fertilised the adjacent coast. The persistent net export of suspended solids and ammonium suggests the higher biological productivity of Ria Formosa compared to that found in coastal waters. In the Winter campaign, after a period of rainfall and increased land runoff, there was a remarkable export of matter, on which, ammonium and suspended particles exported can exceed 0.3 times and almost 0.9 times, respectively, those imported from coastal water. However, the import of phosphate and nitrate can be attributed to a weak coastal upwelling event, as well to low consumption and nitrification at this period of low temperature. During the Spring and Autumn campaigns, the Ria Formosa was fertilised either by upwelling events or due to rapid consumption of nutrients by phytoplankton in this shallow system. BFO and the other two inlets of the western sector of Ria Formosa are interconnected by CF and CO. The higher nutrient transport was recorded at CF, despite the highest nutrients concentrations was recorded at CO. The data show the strong link between physical and biogeochemical processes with meteorological/oceanographic factors. The study showed that associated biological processes are superimposed on the tidal effect in this system. Data from this study could be used as a reference, particularly important for management of Ria Formosa, a productive system where bivalves production depends deeply on water quality. In addition, the nutrient concentrations and mass exchanges resulting from the different processes can be used as a reference for other lagoon systems where shellfish production is practised. • Exchanges of mass were estimated between Ria Formosa (RF) and the adjacent ocean. • Among the three inlets, BFO arose as the most important regarding mass exchanges. • The net tidal prism was highest during spring tides. • RF fertilised the ocean but being also a sink of dissolved and particulate material. • Meteorological/oceanographic and biological processes superimposed on the tides. [ABSTRACT FROM AUTHOR]

Coastal lagoons are among the most productive ecosystems in the world, and they provide a wide range of ecosystem services and resources. In the Ria Formosa (southern Portugal), phytoplankton production has rarely been addressed. The main goal of this study is thus to evaluate the variability of phytoplankton production and photosynthetic characteristics over the seasonal cycle and in different locations (landward, urban, intermediate, and seaward boundaries) of the Ria Formosa coastal lagoon, subjected to distinct natural and anthropogenic stressors. Primary production was evaluated using the 14C incorporation technique, and photosynthetic parameters were estimated by fitting photosynthesis-irradiance curves. Primary production showed significant seasonal variations, with higher values in the summer associated with lower euphotic depths, higher water temperatures, and higher nutrient concentrations. No spatial differences were found for primary production or photosynthetic parameters. Primary production values were lower than previous estimates, which reflects an improvement in water quality in the Ria Formosa, but values are higher than primary production estimates for other temperate coastal ecosystems, which reflects the highly productive nature of this coastal lagoon. [ABSTRACT FROM AUTHOR]

The Ria Formosa, Southern Portugal (Algarve) is a mesotidal lagoon with restricted exchange with Atlantic Ocean. Due to arid Mediterranean climate and absence of large freshwater inputs, the lagoon remains hypersaline relative to adjacent ocean (≥37 psu). Generally, fecal coliforms and land-derived bacteria do not survive long in seawater due to UV, osmotic shock, oligotrophy and competition with marine bacteria. However, survival of human pathogenic viruses in natural waters remains relatively unknown. In view of 2020–2021 SARS-CoV-2 pandemic, this preliminary study aimed to estimate potential contamination by wastewater and persistence in marine environment. Five sampling campaigns (45 total samples) were completed in 2020 and 2021 at three stations in the lagoon, as well as inflow and outflow from three wastewater treatment plants (WWTPs). Despite relatively high fecal contamination at lagoon stations, SARS-CoV-2 could not be detected in surface waters using improved methodology. Untreated wastewaters were positive at Faro-Aeroporto 21/10/2020, 14/12/2020, 08/03/2021; Vilamoura 21/10/2020, 14/12/2020; Olhão 14/12/2020. All treated wastewaters were negative, as well as environmental samples. Highest viral titers were observed in Faro-Aeroporto WWTP on 8 March 2021 (1.35 x 105 genomic copies L−1) coinciding with peak SARS-CoV-2 cumulative positive cases in Algarve (2.03 x 104), yet SARS-CoV-2 was not detected in Vilamoura and Olhão raw wastewater then. Thus, the contamination potential of SARS-CoV-2 seemed non-existent in the Ria Formosa during peak pandemic surges in Algarve. However, predicted climate change and its impact on microbial populations remains a challenge to be addressed by both health and tourist authorities.

The Ria Formosa is an important transitional and coastal lagoon on the south coast of Portugal that provides valuable ecosystem services. The lagoon is a protected area under national and international conventions. There is a great potential for Blue Growth sectors, such as aquaculture and coastal tourism, but these rely on good water quality. European environmental legislation, such as the Water Framework Directive, requires member states, such as Portugal to implement management measures if a surface water body is not of good ecological status. This work addresses the effectiveness of management measures, such as wastewater treatment plant implementation and dredging, on the water quality of the Ria Formosa coastal lagoon system. This is an important social-ecological issue, since management measures can be very expensive. The ecological status of Ria Formosa was evaluated, according to the physico-chemical and biological quality elements of the Water Framework Directive. The main indicators were the physico-chemical quality elements of nutrient and oxygen condition, and the biological quality element chlorophyll a, as a proxy for phytoplankton biomass, under the Water Framework Directive. The data for these quality elements from the Ria Formosa were analyzed for consistency with the classification for the Water Framework Directive water bodies. The data after the implementation of management measures was compared with historical data to evaluate if these measures had been effective. The relation between nutrient pressures, meteorological and hydrological conditions was addressed, especially rainfall and runoff. Results showed a decrease in nutrient concentration after the management interventions, despite the increase of population and intensifying agriculture in the catchment. The Ecological Status is spatially variable with an overall moderate status, indicating the need for further management measures. There is a significant reduction in nutrient pressure on the lagoon during drought years. This indicates that climate change may alter the structure and function of the lagoon in the future.

Recruitment is a critical component of the plant life cycle, but little is known about its contribution to community assembly in comparison to later plant stages. We aimed to analyze the relevance of recruitment niche segregation in community assembly using tidal salt marshes in a Mediterranean climate. With this objective, we recorded the spatio-temporal distribution of seedling emergence and its relationships with propagule density and environmental conditions at the community level along the tidal gradient. Results indicate that seedling recruitment was strongly influenced by differential establishment abilities and the effects of sedimentary and meteorological factors that vary seasonally and along the tidal gradient. Taxa colonizing the same habitats showed some similarities in their recruitment patterns, but they also presented enough differences to configure almost a unique recruitment pattern for each taxa. Sediment characteristics segregated recruitment niches at both extremes of the tidal gradient, and the few species colonizing habitats between these two extremes also showed contrasted spatial recruitment patterns. In addition, sequential differences in seedling emergence segregated within high marsh taxa. Most of the taxa exhibited a continuous germination strategy associated to prolonged flowering periods and the ability to germinate along broad salinity ranges. Our results shed light on the importance of recruitment niche segregation to the assembly of plant communities, which is key for understanding their functioning and guiding their management. • Seedling recruitment was strongly influenced by differential establishment abilities. • Seedling recruitment was influenced by sedimentary and meteorological factors. • Sediment characteristics segregated recruitment niches at both tidal extremes. • Sequential differences in seedling emergence segregated within high marsh taxa. • Most of the taxa exhibited a continuous germination strategy. [ABSTRACT FROM AUTHOR]

The alongshore response of dunes to storm events can be extremely variable and, consequently, their capacity to maintain their services, including the protection of hinterland communities. In this study, the role of biotic and abiotic factors determining the magnitude of dune retreat driven by a severe storm along a 60 km barrier island system was investigated. Data from high‐resolution satellite imagery, digital terrain models, and wave propagation models were used in this assessment. The assessed abiotic factors included the backshore volume, dune height, downdrift inlet distance, and incident wave power. The evaluated biotic factor was the vegetation cover, characterized by a vegetation index retrieved from the multispectral imagery. The results revealed large alongshore variability on dune retreat, ranging from negligible impact to ca. 40 m of retreat. All combined factors allowed us to explain up to 70% of the dune retreat variability through a multi‐regression analysis. Among all investigated factors, the major contributor controlling the magnitude of dune retreat was the backshore volume (more robust berms reduced the retreat) followed by the wave power (normal and longitudinal components). Moreover, the removal of local salient features in the dune line caused the straightening of the coastline, highly contributing to the development of dune retreat hotspots. The other evaluated factors had a smaller influence on reducing coastal retreat, including the vegetation, whose contribution to dune protection was around one order of magnitude lower than that provided by the backshore volume. The results highlight the importance of regional assessments to understand the causes behind the large alongshore variability of storm impacts at dunes. They also state the relatively low influence of the vegetation from this climatic region to enhance dune resistance to storms. [ABSTRACT FROM AUTHOR]

The main objective of this article is to understand the relationship that the residents of Fuzeta, a fishing village in southern Portugal, establish with the Ria Formosa Natural Park, through the concept of place attachment. Recent studies on the relationship between individuals and places highlight the importance of this place attachment, but despite its abundant use, it remains in a stage of theoretical underdevelopment. Furthermore, the lack of research on the attachment to Portuguese Natural Parks endowed this research with an exploratory character and led to the need to a new definition of the concept of place attachment and to the construction of a broader analytical model. The attribution and maintenance of meanings and values to the places, implies not only the relationship of people with the physical elements of the territory but also the interactions of individuals with each other, their sharing of history and culture, and other aspects that can either strengthen or weaken people's attachments to places. We propose in this article a new analytical model that includes, at the same time, the factors that participate in the attribution of meanings and values to places, and also those that participate in the place attachment process whether in a contributory way or in a disruptive way. The empirical study presented in this article adopted a qualitative interpretative methodology through the use of semi-structured in-depth interviews. Thus, 26 Fuzeta residents engaged in leisure or professional activities in the Ria Formosa lagoon were interviewed. The interviewees were workers from several professional activities that use the lagoon - such as fishermen and shellfish catchers, restaurant and hospitality workers, as well as those engaged in leisure activities such as sunbathing, recreational fishing, the catching of shellfish and crustaceans, hiking, boating, windsurfing and camping. The results indicate that the inhabitants of Fuzeta have a very strong and multidimensional attachment to the Ria Formosa that is related to the meanings, emotions, feelings they attribute to it and mainly to the perception of its irreplaceability. [ABSTRACT FROM AUTHOR]

The main objective of this article is to understand the relationship that the residents of Fuzeta, a fishing village in southern Portugal, establish with the Ria Formosa Natural Park, through the concept of place attachment. Recent studies on the relationship between individuals and places highlight the importance of this place attachment, but despite its abundant use, it remains in a stage of theoretical underdevelopment. Furthermore, the lack of research on the attachment to Portuguese Natural Parks endowed this research with an exploratory character and led to the need to a new definition of the concept of place attachment and to the construction of a broader analytical model.The attribution and maintenance of meanings and values to the places, implies not only the relationship of people with the physical elements of the territory but also the interactions of individuals with each other, their sharing of history and culture, and other aspects that can either strengthen or weaken people’s attachments to places. We propose in this article a new analytical model that includes, at the same time, the factors that participate in the attribution of meanings and values to places, and also those that participate in the place attachment process whether in a contributory way or in a disruptive way.The empirical study presented in this article adopted a qualitative interpretative methodology through the use of semi-structured in-depth interviews. Thus, 26 Fuzeta residents engaged in leisure or professional activities in the Ria Formosa lagoon were interviewed. The interviewees were workers from several professional activities that use the lagoon – such as fishermen and shellfish catchers, restaurant and hospitality workers, as well as those engaged in leisure activities such as sunbathing, recreational fishing, the catching of shellfish and crustaceans, hiking, boating, windsurfing and camping. The results indicate that the inhabitants of Fuzeta have a very strong and multidimensional attachment to the Ria Formosa that is related to the meanings, emotions, feelings they attribute to it and mainly to the perception of its irreplaceability.

Coastal lagoons are among the most productive ecosystems in the world, and they provide a wide range of ecosystem services and resources. In the Ria Formosa (southern Portugal), phytoplankton production has rarely been addressed. The main goal of this study is thus to evaluate the variability of phytoplankton production and photosynthetic characteristics over the seasonal cycle and in different locations (landward, urban, intermediate, and seaward boundaries) of the Ria Formosa coastal lagoon, subjected to distinct natural and anthropogenic stressors. Primary production was evaluated using the 14C incorporation technique, and photosynthetic parameters were estimated by fitting photosynthesis-irradiance curves. Primary production showed significant seasonal variations, with higher values in the summer associated with lower euphotic depths, higher water temperatures, and higher nutrient concentrations. No spatial differences were found for primary production or photosynthetic parameters. Primary production values were lower than previous estimates, which reflects an improvement in water quality in the Ria Formosa, but values are higher than primary production estimates for other temperate coastal ecosystems, which reflects the highly productive nature of this coastal lagoon.

Despite worldwide proliferation of the genus Caulerpa and subsequent effects on benthic communities, little is known about the nutritional physiology of the Caulerpales. Here, we investigated the uptake rates of ammonium, nitrate, amino acids, and phosphate through the fronds and rhizoids + stolon, the internal translocation of nitrogen, and developed a nitrogen budget for the rapidly spreading Caulerpa prolifera in Ria Formosa lagoon, southern Portugal. Caulerpa prolifera acquired nutrients by both aboveground and belowground parts at similar rates, except nitrate, for which fronds showed 2‐fold higher uptake rates. Ammonium was the preferential nitrogen source (81% of the total nitrogen acquisition), and amino acids, which accounted for a significant fraction of total N acquisition (19%), were taken up at faster rates than nitrate. Basipetal translocation of 15N incorporated as ammonium was nearly 3‐fold higher than acropetal translocation, whereas 15N translocation as nitrate and amino acids was smaller but equal in either direction. The estimated total nitrogen acquisition by C. prolifera was 689 μmol · m−2 · h−1, whereas the total nitrogen requirement for growth was 672 μmol · m−2 · h−1. The uptake of ammonium and amino acids by belowground parts accounted for the larger fraction of the total nitrogen acquisition of C. prolifera and is sufficient to satisfy the species nitrogen requirements for growth. This may be one reason explaining the fast spreading of the seaweed in the bare sediments of Ria Formosa where it does not have any macrophyte competitors and the concentration of nutrients is high. [ABSTRACT FROM AUTHOR]

Copyright of Pasos: Revista de Turismo y Patrimonio Cultural is the property of Universidad de La Laguna, Instituto Universitario de Ciencias Politicas y Sociales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Jacob, J.; Correia, C.; Torres, A.F.; Xufre, G.; Matos, A.; Ferreira, C.; Reis, M.P.; Caetano, S.; Freitas, C.S.; Barbosa, A.B., and Cravo, A., 2020. Impacts of decommissioning and upgrading urban wastewater treatment plants on the water quality in a shellfish farming coastal lagoon (Ria Formosa, South Portugal). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 45–50. Coconut Creek (Florida), ISSN 0749-0208. Ria Formosa is a productive coastal lagoon, located on the south coast of Portugal, and represents the largest national producer of shellfish bivalves (ca. 90% production). This ecosystem is subjected to various anthropogenic pressures, including the discharge of urban wastewater treatment plants (UWWTP), which impacts the lagoon water quality. This study aimed to assess the impact of alterations in the functioning of two UWWTP on the water quality of Ria Formosa, based on chemical variables, phytoplankton composition (including potential harmful species) and faecal contamination. During the period September 2018 - October 2019, water sampling was conducted along dominant longitudinal gradients of the effluent dispersion from the discharge point (1-2 km), for two sites: a decommissioned (OP) and a modified (FO) UWWTP. After modification, the later started receiving a higher influent volume (ca. 40%), under an innovative technology system (biological treatment in aerobic granular sludge). Based on chemical water quality variables, phytoplankton and indicators of faecal contamination, a significant improvement along the longitudinal gradient from the discharge point was observed after OP decommissioning. This improvement was fast, being detected two months after decommissioning, positively affecting areas used as shellfish farming grounds. However, distribution patterns of bacteriological indicators and regular shellfish harvesting interdictions suggested an alternative source of faecal contamination after OP decommissioning. At FO, both chemical variables and bacteriological indicators of faecal contamination revealed a slower improvement, only six-months after the UWWTP alteration. Before that, increased and highly variable ammonium, chlorophyll a concentration, phytoplankton abundances and Escherichia coli densities, revealed an unstable phase. Overall, a lower water quality at FO in respect to OP reflected not only a higher effluent volume but also more restricted water circulation for the former. [ABSTRACT FROM AUTHOR]

In the Algarve the potential for birdwatching tourism is widely recognized, especially in the Ria Formosa Natural Park (RFNP). This study aims to describe birdwatchers’ profile in the RFNP. For this purpose, a survey was applied. The results show that the most frequent nationalities of birdwatchers are: British (39%), Dutch (17%) and Portuguese (17%). The majority of birdwatchers are male (55%) and married (57%). The average age is 50 years old. They are highly educated (74% have an academic degree). Concerning profession, the most frequent answer was retired (41%). Respondents are committed to the activity as the majority possess special equipment and practice birdwatching in vacations. This study also tests if nationality is related to other characteristics of the birdwatchers, by using the Kruskal-Wallis and the Chi-square tests. Overall, the results of this study highlight that regional management organizations should invest in developing birdwatching in the RFNP.

To examine the extent to which human activities near the Ria Formosa coastal lagoon influence the accumulation of trace elements (TE) in Ruditapes decussatus, individuals were transplanted from a natural bank located in the lower lagoon to three sites located in clam growth grounds under the influence of a small city (Faro), a fish farming centre (Olhão) and a site near the lagoon inlet (Lavajo). Concentrations were determined in substrate of the clam grounds and in the digestive gland, gills, mantle plus siphons, and remaining tissues of clams in four periods of the year. These measurements were accomplished with the monthly survey of the gametogenic stages, condition index, proteins, glycogen, total lipids, pH and osmolarity of hemolymph. Arsenic, Cu, Mn, V, Cr and Pb were preferentially linked to the digestive gland, while Cd was linked to the gills. TE concentrations in the digestive gland and remaining tissues were higher in winter, most likely reflecting additional inputs associated with rain. The lack of disruptions in biological parameters and the prolonged period of spawning and gonad recovery in clams suggest that the current TE availability in the lagoon has a minor influence on the reproductive cycle and hence on clam production.

Abstract Despite the advances and increase of observations of physical and chemical processes to better understand the functioning of coastal environments, a large gap still exists in quantifying exchanges and interactions between adjacent coastal systems. It is important to bear in mind that the dynamics and mass exchanges depend on the variability of the driving mechanisms and respond to several time scales (tidal, seasonal and inter-annual). The general objective of this work was to unravel the role of the driving forces on the nutrients and chlorophyll- a exchanges at the Ancão inlet of Ria Formosa lagoon during the most productive season - spring. This is the smallest inlet of the western system, the closest to continental interface and the one where migratory patterns are evident. So, the changes along time could be more evident there than at the other two inlets of the western sector. Ancão inlet will serve as a reference to compare the mass budgets exchanged with the ocean with the other two inlets. Specifically, this work intends to: i) better understand the behaviour of this inlet; ii) its role in the mass exchanges; and iii) its interplay with phytoplankton productivity during the peak season. In this context, the transport of water, nutrients and chlorophyll- a (proxy of phytoplankton density) were estimated across the Ancão inlet section during the spring season. Surveys were conducted under extreme fortnightly tidal conditions during 2007, 2009 and 2012, covering different hydrodynamic, meteorological and environmental conditions. To estimate the mass transport, field velocities, nutrients and chlorophyll- a concentrations were measured concurrently along its cross section. Results show that although the hydrodynamic and morphologic changes recorded at this inlet provoked a loss of hydraulic efficiency apparently these did not markedly affect the mass exchanges during the spring productive season. Globally, the contribution and intensity of the meteorological/physical, chemical and biological drivers superimposed those affected by tides, reflected in the differences between the five surveys conducted. Upwelling was frequent during the spring season and played a key role on the exchanges and mass transport through the Ancão inlet. Data also show that nutrients behaved dissimilarly; silicate was consistently exported, nitrate mostly imported, dependent on the intensity of upwelling and biological consumption, while phosphate generally followed the direction of residual circulation. Chlorophyll- a showed a general import except in both 2012 campaigns, when it was exported in small amounts (<1 kg). Data support that during spring season, particularly in periods when upwelling is relevant, the availability of nutrients on the coast will promote afterwards the growth of phytoplankton that enters and fertilizes the Ria Formosa, increasing its productivity. The estimated amounts are relative to the smallest inlet of the western sector of Ria Formosa. In consequence, it may be anticipated that through the other main inlets from this sector the exchanges are intensified and may enhance their contribution to the Ria Formosa fertilization. Highlights • Role of driving forces in mass transport in the Ancão inlet, Ria Formosa is presented. • Morphologic changes at Ancão inlet did not affect markedly the mass exchanges. • Physical/meteorological and biological drivers superimposed those of tidal conditions. • During spring, under upwelling events, the coast further fertilizes the Ria Formosa. • Changes at Ancão inlet might affect the interconnectivity with the other main inlets. [ABSTRACT FROM AUTHOR]

Holocene evolution of the Ria Formosa barrier island system was studied through the examination of a large subsurface dataset acquired from 191 boreholes and five seismic refraction profiles. Two boreholes with total depths of 26 and 16.5 m were selected for a multi-proxy detailed laboratory analysis, including mean grain size distribution, organic matter (OM) content, color variation, shell identification, and benthic foraminifera assemblages. Selected cores are thought to be representative of the identified depositional sub-basins. Subsurface age data from 16 AMS 14C dated samples were plotted against depth and resulted in a coherent age model of sedimentary infill. The system evolution was largely controlled by sediment availability, accommodation space, and Holocene sea level rise, first at a rapid rate of 7 mm/yr from 10 kcal yr BP to 7.25 kcal yr BP, followed by a slowdown to 1.1 mm/yr until present. A conceptual model for the origin and Holocene evolution of the Ria Formosa barrier island system implies three main steps, leading to the present system geomorphology: (1) marine flooding of incised palaeovalleys by the rapid transgression of palaeovalleys in the early Holocene; (2) development of a proto-barrier island chain perched on Pleistocene detritic headlands and steeper interfluve areas during the early to middle Holocene; and (3) full development of the barrier islands chain and enclosing of the coastal lagoon, followed by the maturation of the system with subsequent siltation and salt marsh expansion from the middle Holocene until present. The onset of barrier system formation dates back to ca. 8 kcal yr BP, predating previously proposed age. [ABSTRACT FROM AUTHOR]

This paper illustrates both the potential and challenges of interdisciplinary collaboration amongst researchers from the social sciences/humanities and the natural sciences/engineering in formulating disaster risk reduction measures for coastal regions. The authors aim to share their experiences of working across different scientific and engineering disciplines in the EU project RISC-KIT to co-produce disaster risk reduction measures suitable for specific regional and local contexts, in this case two coastal study areas in Europe (Porto Garibaldi, Italy and Rio Formosa, Portugal). An overview of the historic-cultural origins of scientific disciplines is first presented, explaining the historical fragmentation of scientific knowledge into natural and social sciences and its associated challenges for prior disaster risk studies – and how the current state of an interdisciplinary approach has emerged. This is followed by an analysis of interdisciplinary collaboration, drawing on the experience and data collected (both quantitative and qualitative) from the two case study areas. The article concludes with suggestions to further overcome the segregation of disciplines within disaster risk studies and projects. The authors found that qualitative data help to understand knowledge, values and behaviours of institutional and non-institutional stakeholders in formulating appropriate risk reduction measures to increase resilience in a local context – and that such data work “hand in hand” with quantitative information. Furthermore, the collection of qualitative data by researchers of the natural science and engineering disciplines has the potential to build bridges between disciplines and to stimulate further investigations, as in this case, to explain contradictions in human behaviour when managing risk. [ABSTRACT FROM AUTHOR]

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Subterranean estuary seepage faces are recognized as important reactive interfaces that regulate solute transport to coastal ecosystems via Submarine Groundwater Discharge (SGD). Here we describe benthic processes and rates driving the biogeochemical regulation of SGD-borne inorganic N loading into the Ria Formosa lagoon (Iberian peninsula) through a sandy seepage face. Maximum potential NO 3 − reduction rates, obtained by kinetic modeling of advection-controlled flow-through reactor experiments, ranged from 2.33 ± 1.06 to 14.17 ± 0.22 nmol cm −3 “bulk” sediment (bs) h −1 . Maximum potential nitrification ranged from 0 to 7.5 ± 1.3 nmol cm −3 bs h −1 while potential ammonium assimilation was valued at 2.0 ± 0.3 nmol cm −3 bs h −1 . These NO 3 − reduction rates are in good agreement with previous estimates obtained by diagenetic modeling of in-situ porewater NO 3 − vertical profiles at the same location. Potential NO 3 − reduction rates were very sensitive to temperature (Q 10 = 3.5 ± 0.2). Porewater velocity seems to control net NO 3 − reduction rates, probably by determining solute distribution but also its supply to the microbial community by shaping the diffusive boundary layer around sediment particles. Nevertheless, NO 3 − reduction rates seem ultimately limited by organic matter availability at high velocities. Half-saturation constants of NO 3 − for NO 3 − reduction were low, suggesting that the NO 3 − reducing microbial community had high affinity for NO 3 − . In addition, our experiments provide evidence for the occurrence of alternative NO 3 − reduction pathways, including Dissimilatory Nitrate Reduction to Ammonium (DNRA) and apparent aerobic NO 3 − reduction within the shallow subsurface sediment layer (2–12 cm depth). [ABSTRACT FROM AUTHOR]

Interspecific patterns of local population abundances and differences in habitat preference of two seagrass resident pipefish species of the genus Syngnathus were investigated in a semi-protected lagoon system in Southern Portugal. The results of the combination of field surveys across different seagrass meadows and laboratory habitat choice experiments between May and September 2014 demonstrate that the pipefish population structure in a single-species meadow composed of Zostera noltei differed significantly from the ones in a single-species meadow of Cymodocea nodosa and a mixed meadow of both seagrasses. In addition, the two most abundant pipefish species, Syngnathus typhle and Syngnathus abaster , showed interspecific and intersexual differences in habitat selection both on a macro- and a microhabitat scale in laboratory experiments. The study suggests that in addition to the investigated structural characteristics of sea grasses ( i.e. shoot length and density), other factors such as flow velocity may influence habitat selection of syngnathids. [ABSTRACT FROM AUTHOR]

The seasonal and annual nitrogen (N), phosphorus (P), and carbon (C) budgets of the mesotidal Ria Formosa lagoon, southern Portugal, were estimated to reveal the main inputs and outputs, the seasonal patterns, and how they may influence the ecological functioning of the system. The effects of extreme weather events such as long-lasting strong winds causing upwelling and strong rainfall were assessed. External nutrient inputs were quantified; ocean exchange was assessed in 24-h sampling campaigns, and final calculations were made using a hydrodynamic model of the lagoon. Rain and stream inputs were the main freshwater sources to the lagoon. However, wastewater treatment plant and groundwater discharges dominated nutrient input, together accounting for 98, 96, and 88 % of total C, N, and P input, respectively. Organic matter and nutrients were continuously exported to the ocean. This pattern was reversed following extreme events, such as strong winds in early summer that caused upwelling and after a period of heavy rainfall in late autumn. A principal component analysis (PCA) revealed that ammonium and organic N and C exchange were positively associated with temperature as opposed to pH and nitrate. These variables reflected mostly the benthic lagoon metabolism, whereas particulate P exchange was correlated to Chl a, indicating that this was more related to phytoplankton dynamics. The increase of stochastic events, as expected in climate change scenarios, may have strong effects on the ecological functioning of coastal lagoons, altering the C and nutrient budgets. [ABSTRACT FROM AUTHOR]

The artisanal fishery for muricid gastropods in the Ria Formosa lagoon (Algarve coast, southern Portugal) is a locally important fishing activity because the banded murex (Hexaplex trunculus) and the purple dye murex (Bolinus brandaris) are greatly appreciated seafoods with high commercial value in the Portuguese seafood market. An integrated study was implemented to monitor the muricid gastropod fishery with the artisanal fishing gear (“wallet-line”) through monthly experimental fishing operations carried out during one year. The aim was to describe the fishing operations and fishing gear, to estimate the fishing yield, to characterise the target species catch composition, and to identify by-catch species and discards. The “wallet-line” is neither a species-specific nor a size-selective fishing gear, because the catches comprised a variety of by-catch species and a high proportion of commercially under-sized target species. The vast majority of the by-catch is discarded immediately on board, so mortality is presumably negligible. The CPUE of both target species and by-catch species decreased during consecutive fishing days, mainly due to declining bait attraction. Considering the overall information gathered on this fishing activity, some management measures are proposed for this artisanal fishery, which might ultimately contribute to the long-term sustainable exploitation of the fishing resource.

In Ria Formosa cockles (Cerastoderma edule) have traditionally been harvested with a harvesting-knife (HK). However, over the last six years there has been an increase in the use of a hand-dredge (HD) to exploit cockle beds. A comparative study on the impact of these harvesting methods on the benthic macrofauna was undertaken with the aim of evaluating the possible introduction of the hand-dredge in the fishery. Macrofaunal mortality was very low regardless of the gear. However, the total mortality resulting from using the HK was superior to the one observed for the HD. For the same fishing time the hand-dredge covers an area approximately five times greater that the one covered by the knife, with the former yielding 5 times the catch of the latter. Consequently, the use of hand-dredges increases the fishing effort, which may lead to the overexploitation of the cockle populations. Our results revealed that the immediate effect of both gears on macrobenthic communities was similar and minimal. Therefore, we believe that introducing the hand-dredge in the cockle fishery should only be authorised if other management measures, such as daily quotas, closed areas and limiting the number of fishing licenses, are implemented.

A Geographic Information Systems-based tool is used for macro-landform classification following the Hammond procedure, based upon a Digital Terrain Model (DTM) created from ordinary Kriging. Gentle slopes, surface curvature, highlands and lowlands areas are derived from the DTM. Combining this information allows the classification of terrain units (landforms). The procedure is applied to the Ria Formosa basin (Southern Portugal), with five different terrain types classified (plains, tablelands, plains with hills, open hills and hills). [ABSTRACT FROM PUBLISHER]

Understanding the influence of the main drivers controlling the circulation and the transport in coastal lagoons is a necessary step towards the description of the dynamics of their ecosystems. Thus, the influence of the main physical drivers on the water exchanges in a multi-inlet barrier island (western sector of the Ria Formosa coastal lagoon, Portugal) was investigated. Several scenarios of tide, wind, bathymetry and point source discharges were simulated using a three-dimensional circulation model and a particle-tracking model. The circulation is adequately reproduced by the hydrodynamic model, with root mean square errors of about 5-8 cm for the water levels and 5-10 cm/s for the cross-sectional averaged velocities in the western inlets and main channels. Wind has a negligible effect on the modelled water levels and cross-sectional velocities, with differences smaller than 1 % between the simulations with and without wind. However, results show that wind influences significantly the transport by affecting the residual circulation, with distinct effects depending on the wind direction. Upwelling favourable winds (with west component) increase the landward transport through the Faro-Olhão inlet and promote a larger dispersion of the water-borne material inside the lagoon. The residual circulation between the three inlets of the western sector of the lagoon is also significantly affected by the bathymetry. Results show a decrease of about 50 % of the tidal prism of the Ancão inlet between 2002 and 2011, which reduces its capacity to export waterborne material to the adjacent coastal area and increases the residence times in some areas of the lagoon, with potentially adverse effects on the ecosystems' health. The dispersion of potential contaminants from point sources inside the lagoon to the coastal area depends on the combined effect of the tidal phase and amplitude and the location of the source. Mean residence times for the discharges from the wastewater treatment plants of the western sector ranged from 7 to 18 days. These findings improve the understanding of the influence of the physical forcings in the circulation and transport dynamics of multi-inlet coastal systems. [ABSTRACT FROM AUTHOR]

Ria Formosa Lagoon is the most important region for bivalves production in the South Portuguese coast. This study evaluates the microbiological contamination of molluscs Ruditapes decussatus originating from two bivalves production areas of Ria Formosa (a more populated area, Faro–Marchil, and a less populated area, Cacela–Vila Real de Santo António) that were analysed monthly during 1 year. The levels of Escherichia coli and Vibrio spp. were followed and related with temperature profiles. The highest levels of E. coli were found in bivalves collected from Marchil during periods of higher temperatures (summer), mainly due to the population increase during the summer in that area. Although the shellfish harvesting production area classification does not lead to a change in the current classification (Class B). In Cacela higher levels of E. coli were observed especially during the winter, probably due to diffuse sources of faecal discharges. For both areas, the highest levels of Vibrio spp. were found in February and March 2013, these months correspond to a higher level of bacterioplankton in Ria Formosa. Lower levels of Vibrios spp. were found in October 2013 in both bivalve production areas. The analysis of this information can be particularly useful in the development of sanitary surveys and evaluate the human health risks associated with bivalves consumption, thence improving the quality of marketed bivalves, result in adding value to the final product.

The clam Ruditapes decussatus was transplanted from a natural recruitment area of Ria Formosa to three sites, surveyed for nutrients in water and sediments. Specimens were sampled monthly for determination of Escherichia coli , condition index and gonadal index. Higher nutrient values in low tide reflect drainage, anthropogenic sources or sediment regeneration, emphasising the importance of water mixing in the entire lagoon driven by the tide. Despite the increase of effluent discharges in summer due to tourism, nutrient concentrations and E. coli in clams were lower in warmer periods. The bactericide effect of temperature and solar radiation was better defined in clams from the inlet channel site than from sites closer to urban effluents. High temperature in summer and torrential freshwater inputs to Ria Formosa may anticipate climate change scenarios for south Europe. Seasonal variation of nutrients and clam contamination may thus point to possible alterations in coastal lagoons and their ecosystem services. [ABSTRACT FROM AUTHOR]

Ria Formosa is a highly productive lagoon in South-Western Europe, supporting 90% of Portuguese clam production. Decreases in shellfish production have been ascribed to deterioration of water quality due to sewage discharges. Nevertheless, a thorough study considering their impact on the whole lagoon system has been missing. This work determined the sewage footprint from the major sewage treatment plants (STP) regarding eutrophication and microbial contamination within a two-year monitoring program. This focused on salinity, oxygen, nutrients, chlorophyll- a and faecal coliforms. Areas closer to sewage discharges showed an evident impact with maximum effects detected at the major STP. However, globally, the Ria Formosa did not show clear eutrophication problems due to high tidal flushing. Ammonium, oxygen, chlorophyll- a and faecal coliforms, unlike the other parameters, showed no seasonality. Microbiological contamination was of great concern and public health issues could be avoided by settling shellfish beds at least 500 m away from discharge points. [ABSTRACT FROM AUTHOR]

Nearshore bathymetry is likely to be the coastal variable that most limits the investigation of coastal processes and the accuracy of numerical models in coastal areas, as acquiring medium spatial resolution data in the nearshore is highly demanding and costly. As such, the ability to derive bathymetry using remote sensing techniques is a topic of increasing interest in coastal monitoring and research. This contribution focuses on the application of the linear transform algorithm to obtain satellite-derived bathymetry (SDB) maps of the nearshore, at medium resolution (30 m), from freely available and easily accessible Landsat 8 imagery. The algorithm was tuned with available bathymetric Light Detection and Ranging (LiDAR) data for a 60-km-long nearshore stretch of a highly complex coastal system that includes barrier islands, exposed sandy beaches, and tidal inlets (Ria Formosa, Portugal). A comparison of the retrieved depths is presented, enabling the configuration of nearshore profiles and extracted isobaths to be explored and compared with traditional topographic/bathymetric techniques (e.g., high- and medium-resolution LiDAR data and survey-grade echo-sounding combined with high-precision positioning systems). The results demonstrate that the linear algorithm is efficient for retrieving bathymetry from multi-spectral satellite data for shallow water depths (0 to 12 m), showing a mean bias of − 0.2 m, a median difference of − 0.1 m, and a root mean square error of 0.89 m. Accuracy is shown to be depth dependent, an inherent limitation of passive optical detection systems. Accuracy further decreases in areas where turbidity is likely to be higher, such as locations adjacent to tidal inlets. The SDB maps provide reliable estimations of the shoreline position and of nearshore isobaths for different cases along the complex coastline analysed. The use of freely available satellite imagery proved to be a quick and reliable method for acquiring updated medium-resolution, high-frequency (days and weeks), low-cost bathymetric information for large areas and depths of up to 12 m in clear waters without wave breaking, allowing almost constant monitoring of the submerged beach and the shoreface. [ABSTRACT FROM AUTHOR]

Benthic foraminifera showed a vertical zonation in tidally influenced salt marshes, which has been used for sea level reconstructions. Growing evidence suggested that freshwater influx, salinity, or the pH of interstitial waters has also an impact on the foraminiferal distribution. A tidal flat and salt marsh transect was investigated in the north-western Ria Formosa coastal lagoon, Algarve, Portugal, to constrain the relationship of benthic foraminifera, halophytes, and pore water properties. The dominance of saltworts from the subfamily Salicornioideae and landward increasing soil salinities depicted evaporation as governing environmental factor. The carbonate chemistry from lagoonal and pore waters identified anoxic tidal flat sediments of as main source of total alkalinity. The alkalinity was lower in the salt marsh, where the p CO 2 was extremely high. Salt marsh pore waters showed a high variability of carbonate system parameters, which mirrored small-scale spatial heterogeneities in the soil. The distribution of textulariid salt marsh foraminifera was confined to the vegetated zones, where their abundance increased with elevation. Calcareous species were frequent on the tidal flat and in the highest salt marsh. Many of them were specialised to high salinities or to extreme and variable environmental conditions. Two levels of faunal change in the salt marsh coincide with vegetation zonal boundaries, mean tide or mean high water levels. The two other faunal changes were related to changes in calcite saturation state or organic carbon concentrations. The proportion of textulariids showed a negative correlation with submergence time or elevation, and a significant correlation with pore water p CO 2. The faunal distribution, pore water calcite saturation, and Ammonia dissolution patterns indicated that calcareous species specialised to tolerate carbonate-corrosive conditions prevailed even at lowest saturation levels. [Display omitted] • Foraminifera and halophytes showed a relationship with pore water properties. • Soil salinity and evaporation are the governing environmental factors. • Agglutinated foraminifera were rather related to pore water p CO 2 than to submergence time or elevation. • Calcareous foraminifera specialised to tolerate carbonate-corrosive conditions prevailed at lowest saturation levels. [ABSTRACT FROM AUTHOR]

The present work aims to characterize Ria Formosa water quality considering its spatial, and temporal variability at two scales: short-term (among seasons) and long-term to evaluate its evolution over the past 40 years, by comparing six historical datasets with data obtained in this study. To attain these goals, four field surveys under different seasons and/or weather conditions were conducted between 2017 and 2019 at seven sites along the Ria Formosa, covering the water bodies specified for this system. In situ measurements (temperature, salinity, pH and dissolved oxygen) and water sampling for determination of nutrients, chlorophyll a and suspended solids were taken every 2 h at each site, during complete semidiurnal tidal cycles. Moreover, these data were complemented with in situ data acquired at a high frequency (every 15 min) by a real time observational station deployed at an inner area, close to a main channel, where the anthropogenic pressure is more intense. Data analysis clearly depict a spatial variability pattern along the Ria Formosa, as well as a temporal heterogeneity, influenced by the contribution of precipitation, sediments, wind and water exchanges with the adjacent ocean. Between sampling sites, the lowest variability of water quality parameters occurred at the boundary coastal station, at the main inlet, in permanent connection with the ocean, while the maximum variability was found at both the lagoon edges, mainly due to the shallowness of the water column. Temporally, the highest concentrations of nutrients were obtained during the Wet/rainy conditions survey, under the influence of runoff. The lowest concentrations of nutrients were attained during the Summer, except for phosphate, due to consumption by phytoplankton. Although the sampling frequency along time has been limited, Ria Formosa water quality data from the last 40 years shows a decreasing trend in nutrients concentration and a marginal increase of dissolved oxygen, suggesting a water quality improvement over time, in contrast with other coastal lagoons that are showing a water quality deterioration due to an increasing anthropogenic pressure. Altogether, these are relevant aspects to consider regarding Ria Formosa present and future management, including climate change and anthropogenic pressures susceptibility assessment and to use them within an international context by comparison with other similar systems. • Spatial and temporal variability of the water quality of Ria Formosa was assessed. • Spatially, the lagoon edges and the estuarine region present the highest nutrients. • Land runoff during Wet survey can justify peak nitrate and ammonium concentrations. • Diffusion processes from the sediments can explain phosphate maximum during Summer. • Temporally, water quality of Ria Formosa has been improved over the last 40 years. [ABSTRACT FROM AUTHOR]

The Ria Formosa is a shallow and multi-inlet coastal lagoon system in southern Portugal, with six permanent connections to the Atlantic Ocean. The western sector of Ria Formosa comprises three of the main inlets, Ancão, Faro-Olhão and Armona, which contribute ~90% of the total tidal prism of the lagoon. Of those three inlets, Ancão and Faro-Olhão supply the minimum and maximum contribution for these exchanges, respectively. Four field surveys were conducted at these two inlets during the upwelling season (from spring to autumn) to determine the influence of upwelling process upon the hydrographic characteristics in spring tidal conditions: i) spring 2009 (Ancão inlet), ii) autumn 2011 (both inlets) and iii) spring 2012 (Faro-Olhão inlet). Water samples were collected hourly (at three levels), along complete semi-diurnal tidal cycles, to determine chlorophyll a (chl a) and nutrient concentrations. At the same time, the water velocity was measured along the cross section to estimate the tidal prism, nutrients and chl a transports. Ancão inlet contributes a much lower volume to the total tidal prisms than Faro-Olhão inlet. The temporal data variability reveals that chl a and nutrient dynamics through these inlets depends not only on the tidal influence and characteristics of the boundary waters, but also on the intensity of the atmospheric and oceanic forcings acting on the adjacent coastal zone. During pulses of coastal upwelling events, more evident in spring season (mainly in April 2009 and May 2012), the two inlets imported chl a and phosphate. In contrast, in the absence of upwelling conditions, due to wind reversals and/or long periods of wind relaxation, both inlets exported nitrate and phosphate, fertilizing the coastal ocean. However, the Ria Formosa is a highly complex hydrodynamic system, and hydrographic temporal differences can be expected at different scales as a result of changes in: i) morphological configuration of the natural inlets, ii) interconnectivity of channels, and iii) the seasonal meteorological and oceanographic conditions. [ABSTRACT FROM AUTHOR]

The Ria Formosa is a tidal multi-inlet shallow-water coastal lagoon located in the south of Portugal, subjected to the dry Mediterranean climate. The tide controls the Ria's exchange with the adjacent shelf for most of the hydrological year except for isolated torrential run-off events. Episodes of low hypoxia reported in the literature may be related to the lagoon's flushing time, affecting its shellfish production valued at 20 - 50 million €y-1. Over the past decades several observational and modelling studies presented values for the capacity of the tide to renovate the water inside the Ria. However, these studies lack either the spatial resolution to yield results unaffected by numerical diffusion or analyze a very limited part of the lagoon's territory. In this work, we use a very-high resolution hydrodynamic model to assess the flushing time exclusively due to tidal forcing inside the Ria Formosa. A bi-dimensional implementation of the finitevolume/ finite-difference Eulerian-Lagrangian hydrodynamic and transport model (ELCIRC) was used, allowing for the local refinement of the computational domain, which best suits the lagoon's complex morphology. The present model configuration was validated for tidal propagation with sea surface elevation collected in 1979/80 at 11 lagoon stations. The validation results show a good agreement between predicted and observed elevations, with root mean square errors lower than 20 cm and skill values higher than 0.98. A set of experiments were carried out by releasing a conservative tracer at different stages of the tide at discrete points of the Ria, where possible environmental hazard hot-spots are located and the flushing e-folding time calculated from the tracer's dilution. The results are discussed taking into account the propagation of the tide in this multi-inlet, meandering topography. Evidence is presented of topographic trapping due to the complex spatial distribution of the phase lags of the semi-diurnal tidal constituents. This evidence explains the significant increase of the flushing time from the inlets to the head of the channels, thus justifying the use of detailed spatial resolution when modelling such a complex system. [ABSTRACT FROM AUTHOR]

São Luis or Ancão Inlet is the most western of the six inlets of the Ria Formosa lagoon, in southern Portugal. This inlet contributes relatively little to the water volume exchange over a tidal cycle (~10%). Temperature, salinity, pH, dissolved oxygen, and chlorophyll a and nutrient concentrations were measured hourly at the surface, at an intermediate level, and near the bottom over a complete spring tidal cycle, at a sampling point in the middle of the inlet. Current velocity was also measured hourly over the entire cross-section of the inlet using an acoustic Doppler current meter. From these parameters, the flow rate and the transport of nutrients and chlorophyll a were calculated and integrated over the complete tidal cycle providing the net transport. The results show that this is a well-mixed dynamic inlet where, during spring tide, the tidal signal is evident particularly for the nutrient and chlorophyll a concentrations. The nutrient concentrations were low (almost depleted), while the chlorophyll a concentrations were high (4–6 mg m–3). The estimated transports through Ancão Inlet revealed that there was a net import of chlorophyll a, nitrate, and phosphate to the Ria Formosa lagoon, while silicate was exported to the adjacent coastal area.

Abstract: 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. [Copyright &y& Elsevier]

Abstract: The role of benthic sandy ecosystems in mitigating loads carried by Submarine Groundwater Discharge (SGD) to coastal marine ecosystems is uncertain. Benthic biogeochemical mediation of -rich submarine groundwater discharge was studied at the seepage face of a barrier island site in the Ria Formosa coastal lagoon (Southern Portugal). Preliminary analysis of porewater distributions at the seepage face during discharge indicated that benthic biogeochemical processes could significantly affect the fluxes of groundwater-borne into the lagoon. In order to discriminate between the relative contribution of transport and reaction processes to shape and concentration range evidenced by in-situ porewater gradients, an advection-dispersion-reaction (ADR) model of diagenesis was applied to describe porewater profiles obtained in March, June, September and December 2006. Good agreement between modeled and measured profiles was obtained. Model-derived apparent benthic nitrification and reduction rates ranged from 0.01 to 5.2 mmol m−2 h−1, sufficient to explain gross observed changes in fluxes arriving at the seepage face (up to 70% within the surficial 20 cm depth layer). Results of the analysis indicated that the upper limit of the seepage face promoted mitigation of fluxes to the lagoon throughout the year. In contrast, the lower limit of the seepage area promoted net amplification of the fluxes into the lagoon in June and September. These results will help constrain further work aiming to clarify the role of permeable sediments in mitigating nitrogen loading of coastal ecosystems. [Copyright &y& Elsevier]

Frias, P., Horta, J., Almeida, L.P., Pacheco, A., Ferreira, Ó., 2013. Development of a WebGIS tool to determine tidal inlet evolution. In: Conley,D.C., Masselink, G., Russel, P.E.and O'Hare, T. J. (eds.) Research into the consequences of engineering works on the long-term behaviour of inlet systems has been hindered by the absence of suitable datasets, the shortcomings of existing formulae and evaluation tools. Cross-sectional channel areas adjust to hydrodynamics and sediment transport conditions. The impacts of a new inlet on the adjacent shoreline can be unpredictable and are difficult to quantify. This paper presents the development of a Web GIS tool (WebInletAnalyst) that allows any coastal or hydraulic engineer to autonomous extract the evolution of key tidal inlet parameters such as minimum cross-section area, inlet width, maximum depth and migration distance, from a set of bathymetric charts and raw data surveys. The tool is built on a web interface written and compiled using source codes. The tool was applied to a test case (Ancão Inlet, Ria Formosa, Portugal) using available datasets and compared with results from other studies, following the Coastal Engineering Manual guidelines. Overall results showed that mean differences between manual and automate techniques were small and randomly distributed. The user' definition of the location and orientation of minimum cross-section profile affects the accuracy of the tool. Further improvements on the available web interface tool are being tested to allow a magnified view of the inlet channel area and a better precision on sketching the minimum cross-section profile. The tool will be ultimately made available on Python code, allowing future further improvements and adaptations by the scientific community. [ABSTRACT FROM AUTHOR]

Polychlorinated biphenyl (PCB) congener concentrations and organic matter content were determined in 84 samples of suspended and settled sediments collected from six different locations in the Ria Formosa lagoon (Portugal). Total PCB (tPCB) concentrations were higher in the suspended matter (1.00–39.80 ng g–1 dw) than in the sediments (0.10–2.10 ng g–1 dw) and, in general, the same was true for the organic matter. Partial least squares (PLS) analysis using the suspended sediments as signatures indicated that they better explained the settled sediment pattern compared to the reverse. This suggests a suspended sediment source outside the lagoon as source of these PCBs. PLS analysis also indicated that Aroclor 1242 best explained the congener pattern in the sediments, but lower fits were obtained for the suspended matter. The tri- and tetra-chlorinated biphenyls were the most abundant congeners (about 60% of tPCB), followed by the hexa- (20%), penta- (11%) and hepta + octa-chlorobiphenyls (9%). The principal congener differences between the suspended and settled sediments were for the smaller tri- and tetrachlorinated biphenyls, which were preferentially accumulated in the settled sediments. In contrast, congener 49 was significantly more abundant in the suspended phase and may be formed through the anaerobic UV degradation pathway either in suspension or on the surface of strongly anoxic sediments at low tide.

The present work analyzes the concentrations of various metals (Ag, Cd, Cr, Cu, Ni, Pb and Zn) in the edible part of the mussel Mytilus galloprovincialis from the Ria Formosa lagoon (Portugal). Mussels of a similar size (5–7 cm) were collected. The results indicate that the dispersion and accumulation of metals in mussels is influenced essentially by the sources of pollution and the bioavailability of the metal. The highest concentrations of Ag, Cu and Ni occurred in the mussels from sites 1, 6 and 7, which are mainly related to inputs from urban discharges. The highest concentrations of Cr were found in the mussels from sites 2 and 5, located near urban discharges and metallic structures. The highest concentrations of Pb were recorded in the mussels from site 9, associated with fuel from boats and diffuse inputs of this metal. The mussels at sites 3, 4 and 9 presented the highest concentrations of Zn and Cd, probably caused by physical and chemical processes that occur in the boundary between the lagoon and the ocean. The concentrations of Ag and Ni in the mussels of Ria Formosa are relatively low when compared to other geographical locations. The concentrations of Cd, Cr, Cu and Pb accumulated in the mussels reveal low contamination. As for the concentration of Zn, the values in the Ria Formosa mussels are higher in the eastern part of the lagoon than in the western part, revealing signs of contamination by this metal.

Abstract: Coastal shallow lagoons are important ecosystems in terms of their high ecological relevance. They act as buffers of the land–sea interface, providing valuable ecosystem services such as nutrient recycling, decomposition of organic matter and removal of pollutants. Lagoons are regions of restricted exchange, subject to anthropogenic pressures that result in problems such as eutrophication. Because they are shallow, submerged primary producers play a prominent role in lagoon system metabolism. Furthermore, coastal lagoons are particularly vulnerable to global climate change and may act as ‘sentinel systems’. Sea level rise already threatens to overwhelm some lagoons, such as Venice and Moroccan lagoons. Recent observations and studies have shown that a global climate change, especially the warming of the climate system and the sea level rise is unequivocal (IPCC, 2007). Therefore, the dCSTT-MPB model, which deals with nitrogen and chlorophyll concentrations in the water column and within the sediments, was used to explore a range of scenarios that aimed at representing these changes. The tendency of the light limitation due to the sea level rise is the potential degradation of the microphytobenthos community. This reduction would lead to stronger nitrogen fluxes from pore water to the water column, increasing significantly the nitrogen concentrations. No increase in the phytoplankton community was found because it is mainly influenced by the resuspension of microphytobenthos. High nitrogen concentration may be the first indication of an eutrophication event. Nonetheless, nitrogen may be exported to the sea and cause problems in the adjacent coastal waters. The increase in temperature did not lead to significant differences. [Copyright &y& Elsevier]

Abstract: There are numerous studies dealing with larvae of Small Pelagic Fish (SPF), but only a few have actually addressed advanced larval phases. Temperate coastal lagoons are particularly understudied, due to the absence of standard method to capture advanced larval fish in these near shore shallow habitats. Accordingly, this study aims to describe abundances, nutritional condition and in situ growth of post-flexion (SPF) from the Ria Formosa, a tidal coastal lagoon in southern Portugal. The nutritional condition and in situ growth were determined through cohort analysis and standardized RNA:DNA ratio (sRD), complemented with feeding incidence (gut content) and fatty acids (FAs, trophic biomarkers) of postflexion larvae sampled sequentially with light traps, from spring 2005 to summer 2006. Simultaneously, environmental parameters such as water temperature, salinity, dissolved oxygen and chlorophyll a were measured. Post-larvae of SPF were captured through the year in important numbers. The dominant species were Sardina pilchardus (50.7%), Engraulis encrasicolus and Atherina presbyter (11.4%). These results are distinct from those based on adult/juvenile surveys or early planktonic phases in the Ria Formosa where clupeiformes were occasionally reported. Sardines were captured mainly in winter, spring and early summer and anchovies mainly during summer and autumn. Sand smelt, a resident species, was present throughout the year. In the early summer, the three species were present and during this period some diet overlapping occurred, the feeding incidence of the clupeiformes was very low, but atherinids always exhibited full guts reflecting the different gut morphology or indicating different life-cycle strategies. The bulk of the diet was mollusks, crustaceans and appendicularians, for sand smelts, sardines and anchovies, respectively. The results of FA analyses showed some contribution of phytoplankton to SPF in the area. All SPF exhibited higher condition (sRD) and growth rates in summer, which are explained by the adequate temperature and higher planktonic productivity. This is especially relevant because the successful development of postflexion larvae in these nursery areas largely determines the successful recruitment to adult fish populations. [Copyright &y& Elsevier]

The dynamics of the seagrass Zostera noltii in established and colonizing meadows were assessed in Ria Formosa lagoon, Southern Portugal. Shoot weight, above:belowground biomass ratio, flowering shoot density, meadow production, and biomass-density relationships were investigated. Results indicate that the species population dynamics differ clearly in different development stages of the meadows. The overall mean of flowering shoot density was five times higher in the colonizing (83 flowering shoots m−2) than in the established meadow (16 flowering shoots m−2), revealing a greater contribution of sexual reproduction during the species colonization process. The temporal variation of the biomass-density relationship in the colonizing meadow showed a cyclic seasonal trajectory, a wider range of data, and a simultaneous peak of biomass and density, suggesting no space limitations constraining the internal packing of shoots during the growing season. In the established meadow, density peaked before biomass in agreement to the dominant role of the clonal architecture of seagrasses in the configuration of closed meadows, suggesting the occurrence of self-thinning and/or regulation of ramet formation. Slope of the biomass-density relationships was similar in the established and colonizing meadows, generally suggesting similar nutritional conditions, regardless of their muddy and sandy sediments. Plants of the colonizing meadow invest mainly on the belowground fraction (above:belowground biomass ratio <1), as meadow expansion is mainly controlled by the elongation of horizontal rhizomes. The annual total production (1163 g C m−2 year−1) and the biomass turnover (34.8 year−1) were also higher in this meadow, corroborating the high investment of the species during the meadow expansion. The faster biomass turnover of the colonizing meadow implies a more limited capacity to accumulate biomass, indicating a greater exportation of organic carbon and nutrients to the coastal area. The different biomass turnover rates suggest different trophic and structural roles of Z. noltii communities in established and colonizing meadows. [ABSTRACT FROM AUTHOR]

Abstract: This study investigates the effect of entrance/exit losses on the cross-sectional stability of double inlet systems. The inlet is in equilibrium when the sand transport into the inlet equals the sand transport out of the inlet. The velocity amplitude corresponding with the equilibrium cross-sectional area is referred to as the equilibrium velocity (∼1 m s−1). This equilibrium is stable when after a perturbation the cross-sections of both inlets return to their original equilibrium value. The amplitudes of the inlet velocities are obtained using a lumped-parameter model in which the basin water level fluctuates uniformly (pumping mode) and where the inlets are schematized to prismatic channels. The system is forced by a semi-diurnal tide, where amplitude and phase may differ between the two inlets. Previous studies concluded that for double inlet systems no stable equilibriums can be found. However, in these studies entrance/exit losses were neglected. In the present study entrance/exit losses are included in the dynamic equation of the inlets. Using an analytical model it is shown that entrance/exit losses and a difference in the two ocean tidal amplitudes are a prerequisite for the existence of stable equilibriums. Furthermore, the effects of the addition of bottom friction and inertia to the dynamic equation are investigated using a mathematical continuation method. The results show that, provided entrance/exit losses are considerably larger than bottom friction and inertia, stable equilibriums are possible. These conclusions are supported by observations in the Ria Formosa, southern Portugal. Care should be taken in using the stability model described in this paper as a predictive tool due to simplifications in the model and the uncertainty in determining certain parameter values including inlet length, entrance/exit loss coefficient, bottom friction factor and equilibrium velocity. To alleviate these shortcomings suggestions are made for future research. [Copyright &y& Elsevier]