Ria De Aveiro Coastal Lagoon Research Articles

Impact of Extreme Wind and Freshwater Runoff on the Salinity Patterns of a Mesotidal Coastal Lagoon

The interaction between tide, river runoff, and wind in coastal lagoons induces complex salinity gradients, which are remarkable when the meteorological forcing is exacerbated. This work aims to characterize the salinity structure under extreme freshwater and wind events in the Ria de Aveiro coastal lagoon (Portugal). The Delft3D model was implemented and validated in 3D mode and used to perform simulations forced with extreme freshwater and wind scenarios. Results show that forcing conditions determine salinity stratification intensity and location. Generally, stratification increases as the freshwater increases, while the salinity intrusion moves downstream. Extreme wind tends to destroy stratification but fails to promote full-depth mixing, which is also dependent on the wind direction, as shown for the Espinheiro channel. The salinity intrusion is also impacted by wind events, being NW storms responsible for an upstream salt transport along the Mira channel and a downstream transport along the Espinheiro channel, and SW storms for an upstream displacement of the salinity intrusion along the São Jacinto channel. Finally, it is observed that the advection of a freshwater plume from the Vouga River into the middle of the São Jacinto channel under high freshwater scenarios causes an unusual local salinity pattern. This plume can either be pushed upstream or prevented from entering the channel, depending on the wind direction.

High risk water pollution hazards affecting Aveiro coastal lagoon (Portugal) – A habitat risk assessment using InVEST

Anthropogenic pressures put at jeopardy ecosystem services (ES) provided by natural habitats. Ecosystem Based Management (EBM) approaches can support policymakers dealing with physical, chemical, and biological stresses caused by high-risk water pollution (HRWP) and sudden-accidental pollution (SAP). The objective of this study is to evaluate how alarming HRWP pressures might become in fragile marine, coastal, estuarine, and freshwater socio-ecological systems (MCEF-SES) surrounded by heavily industrialized and urbanized areas. To this end a spatially explicit analysis, using the InVEST-Habitat Risk Assessment (InVEST-HRA) model in combination with expert judgement from researchers from various fields, is performed. An application is provided for the case of the Ria de Aveiro (RdA) coastal lagoon in Portugal. Results show high spatial variance of HRWP hazards across RdA, with one major multi-layer risk hotspot at the center of the research area and a second patch of multiple risk hotspots towards the North of RdA. Salines emerge as the most threatened habitat followed by Intertidal flats and Saltmarshes. The most significant water pollution risk sources contributing to Salines cumulative risk are Fossil fuel processing, storage and sale units, Industrial units, Aquaculture, and the Marinas. Industries involving dangerous substances in the region threaten primarily Watercourses. This study confirms the InVEST-HRA model in combination with expert judgement is a transparent and easily replicable approach to build ES-based knowledge about habitat risks threatening MCEF-SES in a Natura 2000 site heavily pressured by HRWP hazards. After further valuation analysis, pondering gains and losses from regional development and environmental protection, this knowledge can support the planning and management of coastal areas and the prioritization of pollution abatement interventions. In particular, by estimating the loss that HRWP causes in the value of ecosystem services, defining HRWP abatement policies, assessing the effectiveness, costs and benefits of those abatement policies and, ultimately, evaluating the results for the well-being of local communities through global efficiency analysis, cost-benefit analysis or cost-effectiveness analysis. Hence, it bridges the gap between an informed EBM and the development policies of fragile regions.

A spatial explicit vulnerability assessment for a coastal socio-ecological Natura 2000 site

In line with the global trend, the Ria de Aveiro coastal lagoon is subjected to multiple co-occurring pressures threatening vital benefits flowing from nature to people. The main objective of this research was to assess the status of habitats important for ecosystem services in the Ria de Aveiro by identifying vulnerable areas to anthropogenic threats. The pressures from seven relevant human activities (recreation, services, aquaculture, agriculture, commercial development, unintended impacts from management, and invasive alien species) were analysed based on their spatiotemporal distribution (exposure) and impact over the EUNIS habitats (EUNIS codes A2.2, A2.22 – sand flats and beaches; A2.3 – mud flats; A2.61 – seagrasses; A2.5, A2.53C, A2.535, A2.545, A2.554 – salt marshes; and, X10 – ‘Bocage,’ a landscape of small-hedged fields) in seven distinct landscape units. A prospective scenario, co-developed for the year 2030, was evaluated using a map-based risk assessment tool and brought forward the near-term vulnerability of the seagrass biotope. The highest risks posed to intertidal habitats (mud flats and salt marshes) were driven mainly by environmental management activities that support critical socio-economic sectors. Our methodology evaluated plausible threats to habitats in the near term, established baseline knowledge for the adaptive management process in Ria de Aveiro Natura 2000 site, and showcased how future assessments can inform the operationalization of ecosystem-based management as new information becomes available.

Using Oyster Shells for Customized 3-D Structures for Monitoring Ecosystem Shifts on Ascidians Diversity

Biofouling communities are broadly distributed and there is a growing need to understand, monitor, and prevent their dispersal and colonization. Ascidians are a major group of fouling organisms but have remained poorly studied in this context. Furthermore, the search for improved sustainable practices regarding shipping networks, biofouling management, treatments, and monitorization has made headway rapidly. The present study surveyed and established a baseline for the ascidian biofouling community in a coastal lagoon, by operationalizing the concept of artificial substrate units (ASU) through a customized 3-D unit with the shape of a triangular-based pyramid, a nature-based structure that simulates natural habitats, made with oyster shells sourced from local aquaculture farms. The ASU were grouped into a five-replicate star-shaped, to be collected at each sampling moment. Throughout the 295 days (from May to December of 2020) of the present study covering five different locations of Ria de Aveiro (Portugal) coastal lagoon, a total of 12 species of ascidians were collected. While Ascidiella aspersa, Microcosmus sp., and Molgula sp. 1 were registered in all the locations surveyed, the remaining nine ascidian species were dominant only in specific locations of the coastal lagoon. Values of total abundance presented an overall increasing trend in all locations surveyed, with maximum values corresponding to summer periods. Two locations (Oyster Farm and Integrated Multi-Trophic Aquaculture Farm) recorded the highest abundance values. The present findings demonstrated that the ASU employed using oyster shells, a widely available co-product of oyster farming, can be considered an efficient support structure for short- or long-term monitoring of the ascidian community, as well as fouling communities in general. Hydrodynamics, seasonality, and nutrient-enriched waters were the main contributors to the establishment of ascidians. For the first time, Clavelina lepadiformis and A. aspersa were collected and reported in coastal waters of mainland Portugal. While preventing the settlement of fouling communities can be extremely difficult, an improved understanding of existing communities of these organisms can undoubtedly contribute to the development of improved management practices to control them. An updated list of all ascidian species recorded to date from coastal waters of mainland Portugal is also presented.

Checking the changes over time and the impacts of COVID-19 on cockle (Cerastoderma edule) small-scale fisheries in Ria de Aveiro coastal lagoon, Portugal

Historical information on cockle landings and studies on local knowledge on cockle fishing, zoology, and ecology in the Ria de Aveiro remain incomplete. Due to the COVID-19 pandemic and the current conditions of artisanal fisheries in Europe, understanding the dynamics of this activity has become even more necessary. Therefore, this case study sought to investigate the changes that have taken place in recent cockle fishing decades and verify the degree of contentment of these fishers with the rules for cockle fishing during the current pandemic period. LEK showed a downward trend in cockle stock on a time scale of around 60 years. Members of these fishing villages have not experienced the shifting baseline syndrome. This traditional fishery proved susceptible to the intense fishing effort, increased fishers, decreased commercial-sized adult individuals, and increased incidence of biotoxins and diseases in the cockle. Fishers were not content with the measures and circumstances imposed on cockle fishing during the COVID-19 pandemic between 2020 and 2021. The main points related to the discontent were about income and government financial support to fishers. Synergistic initiatives covering all those involved with the cockle bioresource are essential for the sustainability of this resource of great socio-ecological importance for the Iberian Peninsula. Health efforts and governance are also recommended for the optimal functioning of this fishery during the pandemic period. The application of policies and rules coming from participatory governance can be a way for greater acceptance by fishers and better management of bivalve fisheries in the Ria de Aveiro lagoon.

Omega-3 on the fly: long-legged fly Machaerium maritimae as a potential source of eicosapentaenoic acid for aquafeeds

The need for more sustainable aquafeeds has prompted the exploration of insects as potential ingredients. However, commonly reared insects are not satisfactory regarding their fatty acid composition, lacking omega-3 long chain polyunsaturated fatty acids (n-3 LC PUFA), important nutrients for marine organisms. In this study, we present in detail the fatty acid profile of the long-legged fly Machaerium maritimae Haliday (Diptera: Dolichopodidae), an amphibiotic insect native to European coastal habitats. Specimens of this fly were collected in Ria de Aveiro coastal lagoon (Portugal) and the fatty acid profile was analysed through gas chromatography coupled with mass spectrometry. Results revealed a remarkably high level of n-3 LC PUFA, (11 μg/mg dry weight, 20% of the fatty acid profile) namely eicosapentaenoic acid, and a low level of saturated fatty acids. This value is higher than what is found in Hermetia illucens (black soldier fly), while comparable to other aquatic insects. We also report the presence of 50 distinct fatty acids, including multiple branched-chain and PUFA, and discuss potential implications of their presence on the ecology of this species. Variation in the fatty acid profile along the landscape is also presented. Our results indicate that M. maritimae can potentially be a high-quality lipid source for marine aquafeeds. Current legislation in Europe allowing the use of insects in aquaculture is restricted to a few selected species, often non-native, however, further research should consider native insects as potential alternatives to current ingredients in aquafeed.

Use of hyperspectral reflectance to non-destructively estimate seagrass Zostera noltei biomass

Seagrasses are marine plants ranked worldwide amongst the most valuable coastal ecosystems. The global conservation effort requires accurate estimation of seagrass abundance and taxonomic composition. Hyperspectral reflectance has been used to estimate seagrass biomass, despite requiring destructive laboratory measurements that goes against conservation principles.Therefore, we assessed the efficiency of Zostera noltei hyperspectral reflectance to estimate its aboveground biomass in intertidal areas, having Ria de Aveiro coastal lagoon (Portugal) as a case study, with seasonal samplings during a whole year comparing (non-destructive) field- and (destructive) laboratory-based measurements of the spectral signature. Several vegetation indices (VIs) that focus on the spectral absorption of specific pigments were also tested: Normalized Difference Vegetation Indices (NDVI)-like ratios, Double Difference (DD)-like Ratios and Simple Ratios (SR).Here we show that Z. noltei hyperspectral signature, measured in the field and in the laboratory, is clearly related to the aboveground biomass of the plant along the year. We found that among the VIs, NDVI-like ratios showed higher correlation with Z. noltei aboveground biomass than the other types of VIs. Taking into consideration the sensitivity to biomass saturation, the NDVI705 was identified as the best vegetation index to estimate Z. noltei biomass during the whole year and in both type of measurements, up to a saturation level, also demonstrating the successful use of non-destructive methods.The suitability of hyperspectral reflectance measurements in order to estimate Z. noltei aboveground biomass was confirmed, confirming also the potential efficient use of field-based measurements (non-destructive) for conservation practices and sustainable management of the species in intertidal ecosystems and allowing aboveground biomass to be potentially proposed as a metric for the evaluation of seagrass healthy condition under EU policies (e.g. Water Framework Directive, Marine Strategy Framework Directive).

A model to integrate ecosystem services into spatial planning: Ria de Aveiro coastal lagoon study

The need to bring ecosystem services into strategic decisions and policy design for the governance of social-ecological systems is found to be mutually advantageous within the scientific and political community, as it may lead to better environmental decision-making and promote sustainable development. However, its actual integration into spatial planning and decision-making processes have not been fully realised and face substantial challenges, particularly regarding the marine environment. This paper uses the Ria de Aveiro coastal lagoon (Vouga estuary, Portugal) and the conceptual framework of Estuary Programmes as a starting point for proposing a model for the gradual incorporation of ecosystem services into policy and decision-making processes. Estuaries are complex social-ecological systems that lay at the interface between marine and terrestrial ecosystems, which are managed through Estuary Programmes – a special programme of strategic nature that aim to protect the natural resources of estuary and estuary banks. Despite having a legal framework since 2009, Estuary Programmes have never been developed, posing an opportunity for improving traditional practices and adapting them according to new methodologies and approaches. The proposed model, with three essential stages, provides a way forward for strengthening the process of environmental planning and management towards sustainability, territorial and social cohesion, responding to current societal challenges and contributing to human well-being. Principles such as comprehensive, adaptive, inclusive, and integrative were established as key for guiding ecosystem services integration into the spatial planning process.

Bioaccumulation and biochemical patterns of Ruditapes philippinarum clams: Responses to seasonality and low contamination levels

Shellfish farming and shellfish harvesting have been practiced for a long time in the Ria de Aveiro coastal lagoon (Portugal). Among commercial bivalves, Manila clam Ruditapes philippinarum represents one of the most important species inhabiting this coastal system. Introduced in Portugal in 1984, naturalised R. philippinarum clam populations have been subjected to several pressures that may threaten this resource sustainable management: illegal fishing, harvesting in chemically polluted sites with impacts on human health and lack of control in terms of productivity with the risk of a progressive decline of the biomass. On behalf of the ASARISAFE project (with the title Safety and sustainable management of valuable clam product in Portugal and China) the environmental quality of Manila clam harvesting sites was evaluated, focusing on inorganic pollution and health status of clams in terms of bioaccumulation as well as biochemical performance. Seasonal sampling campaigns were conducted in six R. philippinarum harvesting areas evaluating inorganic pollution levels, in clam's tissues, sediment and water. Clams biochemical performance in terms of metabolism, energy reserves and oxidative stress was also assessed. The results obtained showed that mercury (Hg) and arsenic (As) were the elements with the highest BAF (Bioaccumulation factor) values, but contamination levels in tissues and sediments varied among sampling areas and seasonal campaigns. The amount of clams consumed per week to exceed Provisional Tolerable Week Intake (PTWI, kg) was the lowest for As, revealing that less 0.05 kg of clams was enough to exceed PTWI. However, the results obtained further demonstrated that the clam's biochemical performance was not responding to tissues contamination levels but were closely related to seasons, with distinct metabolic capacity and oxidative stress levels among distinct sampling periods during the year.

Blue Carbon stock in Zostera noltei meadows at Ria de Aveiro coastal lagoon (Portugal) over a decade

This work assessed the Blue Carbon (C) stock in the seagrass meadows (Zostera noltei) of Ria de Aveiro coastal lagoon (Portugal), and evaluated its spatio-temporal trend over the 2003–2005 to 2013–2014 period. Zostera noltei spatial distribution, restricted to intertidal areas in 2014, was mapped by remote sensing using an unmanned aerial vehicle (UAV) and aerial photography. Zostera noltei biomass was also monitored in situ over a year and its Blue C stock was estimated. By 2014, intertidal meadows covered an area of 226 ± 4 ha and their Blue C stock ranged from 227 ± 6 to 453 ± 13 Mg C. Overall, Ria de Aveiro Z. noltei intertidal meadows increased in extent over the 2003–2005 to 2013–2014 period, corroborating the recent declining trend reversal observed in Europe and contrary to the global decline trend. This spatio-temporal shift might be related to a natural adjustment of the intertidal meadows to past human intervention in Ria de Aveiro, namely large-scale dredging activities, particularly in the 1996–1998 period, combined with the more accurate assessment performed in 2014 using the UAV. This recovery contributes to the effective increase of the Blue C stock in Ria de Aveiro and, ultimately, to supporting climate regulation and improving ecosystem health. However, major dredging activities are foreseen in the system’s management plan, which can again endanger the recovery trend of Z. noltei intertidal meadows in Ria de Aveiro.

Polychaete annelids as live bait in Portugal: Harvesting activity in brackish water systems

Polychaete annelids are some of the most heavily harvested invertebrates collected in coastal areas and estuaries for their economic value as live fishing bait or as food supplement in aquaculture activities. However, information on bait digging in Portugal is scarce or incomplete. Thus, the present study aimed at investigating the bait digging activity in the four most relevant brackish water systems in Portugal: Ria de Aveiro and Ria Formosa coastal lagoons and Tagus and Sado estuaries. Direct observations were performed in each brackish water system 1 h and a half before and after the diurnal low spring tide (<0.8 m height), on working days. Additionally, logbooks were delivered to bait diggers and two types of surveys were conducted in every system: one to all the intertidal users and the other only to bait diggers.The estimated daily weighted number of bait diggers varied between 31 in the Tagus estuary and 69 in the Ria Formosa coastal lagoon. Diopatra neapolitana (Delle Chiaje, 1841) was the main target species in Ria de Aveiro (more than 83%), Tagus estuary (more than 60%) and Ria Formosa (more than 90%), while in Sado estuary most of the bait diggers targeted Marphysa sp. (92.6%). The highest and lowest amount of polychaete annelid catches were estimated for Ria de Aveiro coastal lagoon (almost 50 tons per year) and Tagus estuary (11 tons per year), respectively. A total annual bait catch value in these four systems was estimated as €3.84 millions. The most important brackish water systems concerning bait diggers’ number and bait captures were Sado estuary and Ria de Aveiro coastal lagoon where management measures should be considered, although managing polychaete harvesting activity is still difficult due to limited information on harvesting and on direct and indirect impacts on population dynamics.

Evaluation of long-term estuarine vegetation changes through Landsat imagery

Salt marshes support estuarine biodiversity and provide ecosystem services; however, their general decay is being observed worldwide, in large part due to land reclamation. Accordingly, there is a growing concern about salt marsh preservation status having in mind the promotion of effective management decisions towards their conservation and restoration. Satellite imagery offers the opportunity to monitor land surface dynamics, constituting a fundamental information source for wetland monitoring. This study analyses spatial and temporal vegetation changes within Ria de Aveiro coastal lagoon between 1984 and 2017, by processing and analyzing TM and ETM+ Landsat imagery. A database consisting of 264 cloud-free images was collected and analyzed. The Normalized Difference Water Index was computed using the remote surface reflectance and was then used to distinguish land from water and to estimate the flooded lagoon area. Moreover, the tidal state was determined for each image from a tidal elevation record monitored at the lagoon entrance. Subsequently, four vegetation indices (VI) were computed and their spatial variability in the lagoon area uncovered by water was assessed. Spatially averaged spectral indices were also statistically analyzed and seasonal variations and interannual trends evaluated. Results show that the intertidal area increased, and VI values decreased indicating a possible reduction in the Chlorophyll content and suggesting that the new intertidal regions are mostly covered by mud. The spatially averaged VI values show seasonal patterns, with peaks in spring and summer, coinciding with high biomass productivity periods. The largest flooded area and VI modifications occurred after 1999, suggesting that changes are associated with dredging activities performed in the main lagoon channels. This study reinforced the potential of Landsat archives to monitor coastal wetlands, highlighting their importance for coastal managers of threatened systems, and therefore helping to define management strategies about the ecological conservation of estuarine systems.

Participatory coastal management through elicitation of ecosystem service preferences and modelling driven by “coastal squeeze”

The Baixo Vouga Lagunar (BVL) is part of Ria de Aveiro coastal lagoon in Portugal, which is classified as a Special Protection Area under the European Habitats and Birds Directives. This part of the system, corresponding to the confluence of the Vouga River with the lagoon, is very important culturally and socioeconomically for the local communities, taking place several human activities, especially agriculture. To prevent salt water intrusion from the Ria de Aveiro into agriculture fields, a floodbank was initiated in the 90's. In frame of ongoing changes in Ria de Aveiro hydrodynamics, the existing floodbank will be now extended, introducing further changes in the ecological dynamics of the BVL and its adjacent area. As a consequence, the water level in the floodbank downstream side is expected to rise, increasing the submersion period in tidal wetlands, and leading to coastal squeeze. The aim of this study is to apply an ecosystem based-management approach to mitigate the impacts on biodiversity resulting from the management plan. To do so, we have modelled the implications of the changes in several hydrological and environmental variables on four saltmarsh species and habitats distribution, as well as on their associated ecosystem services, both upstream and downstream of the floodbank. The ecosystem services of interest were prioritized by stakeholders' elicitation, which were then used as an input to a spatial multi-criteria analysis aimed to find the best management actions to compensate for the unintended loss of biodiversity and ecosystem services in the BVL. According to our results, the main areas to be preserved in the BVL were the traditional agricultural mosaic fields; the freshwater courses and the subtidal estuarine channels. By combining ecology with the analysis of social preferences, this study shows how co-developed solutions can support adaptive management and the conservation of coastal ecosystems.

A simple spatial typology for assessment of complex coastal ecosystem services across multiple scales

This paper aims to present and demonstrate the applicability of a methodology to characterise supply and demand for ecosystem services (ES) on the basis of spatial properties and interdependence, and economic properties of ES. The typology is demonstrated to support inclusion of ES flow in social-ecological systems management. Ria de Aveiro coastal lagoon, Portugal, is used as a showcase for the proposed spatial typology for ecosystem services assessment across multiple scales. To address the proposed objective a four-step methodology was developed: i) choice of the management area and definition of the boundaries of the system to be governed; ii) assessment and classification of ES produced or consumed within the management area, where supply or demand of an ES may be endogenous, exogenous or partially exogenous/endogenous; iii) mapping of production and consumption areas covering the major categories of ES (biotic and abiotic provisioning services, regulating and maintenance services, and cultural services) and major types of spatial relationships, which may be independent; interdependent, dependent or controlling; and iv) spatial characterisation of the ES production and benefits based on excludability and rivalness of ES. In Ria de Aveiro from the variety of ES and their spatial relationships we highlight interdependencies between the Lagoon and other locations outside the management area. This approach shows that the proposed methodology can support the understanding of these interrelationships and improve these connections by, identifying inherent transactions and key-actors.

Spatio-temporal variation of trematode parasites community in Cerastoderma edule cockles from Ria de Aveiro (Portugal)

Cerastoderma edule (edible cockle) is among the most exploited bivalves in Europe playing an important socio-economic role. Cockles live in estuaries and lagoons where their population is controlled by several environmental factors including parasitism. Parasites represent an important part of the world known biodiversity but are often neglected. Trematodes are the most prevalent macroparasites of cockles being able to exert an impact both at the individual and population levels. Therefore, it is of prime relevance to recognize and understand the parasite-host system dynamics in order to better predict potential conservation threats to bivalve populations and to maximize the success of stock and disease episodes management.Cockle monitoring was conducted in 2012 and 2016, in six and eight stations, respectively, at the Ria de Aveiro coastal lagoon, Portugal. Cockles were sampled in one single occasion in 2012 and seasonally in 2016. The tested hypothesis is that the trematode community in cockles was spatially and seasonally heterogeneous but stable over time. The main result showed that despite a relative homogeneity of the parasite community structure in cockles, the among-years heterogeneity of trematode communities was higher than among-stations and among-seasons heterogeneity rejecting the postulated hypothesis. Results demonstrated that trematode communities from the Ria de Aveiro are characterized by low abundance, which resulted in a spatial and seasonal trematode homogeneity (despite an overall channel difference and a slight downstream-upstream gradient). The interannual analysis showed a worrisome loss of trematode diversity and prevalence which consequently indicates an important loss of overall diversity and/or environmental conditions reflecting the negative effects of global change (mean temperature rise and overharvesting, among others). The present study highlighted the importance of trematodes in characterising their associated environment and respective biodiversity which might be helpful to assess ecosystem ecological status and to identify threatened areas.

Introducing a Regulatory Policy Framework of Bait Fishing in European Coastal Lagoons: The Case of Ria de Aveiro in Portugal

The harvesting of bait through digging in coastal mudflats is practiced for recreational and commercial purposes in European coastal systems including the Ria de Aveiro coastal lagoon on the northwest Atlantic coast of Portugal. The scale of harvesting in the Ria de Aveiro has recently increased due to the current economic climate in Portugal, with targeting of the polychaete, Diopatra neapolitana species or “casulo” as it is widely known in the Aveiro region. The national authorities have attempted to control casulo digging by issuing a regulation (Ordinance) in 2014 on the maximum daily catch limit to be caught by each individual. The daily catch limit is intended to represent the Maximum Sustainable Yield (MSY) for casulo beyond which overfishing will occur. The monitoring of the regulatory measures is expected to be conducted through on-site inspections in the digging areas. However, weak law enforcement was noticed, while there is also controversy over the daily catch limit (quota) stipulated by the Ordinance. To this end, the current study attempted to assess digging activities through remote monitoring and random inspections for a better policy enforcement of the national regulation. In addition, different harvesting scenarios were employed through a simplified bioeconomic model to attribute the current and future harvesting trends of bait digging in Aveiro coastal lagoon. The study findings indicate that remote monitoring coupled with some onsite interviews could be a more effective approach for the implementation of the current bait digging policy. Further, the results point to a distinctive discrepancy between the daily catch amount (MSY) introduced by the national legislation and the study findings which should be further scrutinized. The diggers seem to have reached the sustainable harvest identified by the present research. The current economic hardship in Portugal and the low profitability in similar employment sectors will possibly attract more diggers and increase harvesting in the near future. An increased harvest would likely trigger overfishing of D. neapolitana with unknown consequences for the population of the species as well as the aquatic ecosystem. The socio-economic and environmental effects are yet to be further clarified with more detailed data and advanced modeling techniques to ensure the sustainability of the activity.

Challenges for the WFD second management cycle after the implementation of a regional multi-municipality sanitation system in a coastal lagoon (Ria de Aveiro, Portugal).

In the scope of the first WDF management cycle, a multi-municipality sanitation system with secondary treatment was implemented in 2005 in Ria de Aveiro coastal lagoon, with the treated effluent discharging into the Atlantic Ocean through a submarine outfall. The lagoon water chemical status was evaluated regarding dissolved inorganic nutrients and chlorophyll a before and after 2005. The S. Jacinto outfall has effectively reduced the point source nutrient loads (ammonium and phosphate) into Ria de Aveiro, representing a step forward for the implementation of the WFD, through eutrophication abatement. However, the lagoon remains exposed to non-point nitrogen sources, as a consequence of the current land use and water management, which in a scenario of winter extreme precipitation events, nutrients increase through surface run-off. Besides, in a combined scenario of low freshwater input into the lagoon and favourable oceanic condition, nutrients enter through Ria outer boundary coming from the S. Jacinto outfall. Thus, changes in the system hydrodynamics in the context of global change might pose new challenges regarding the WFD second management cycle involving the second river basin management plan and the first flood risk management plan, foreseeing the 'Good' ecological status in all Ria's Water Bodies.

Assessment of flood hazard during extreme sea levels in a tidally dominated lagoon

The inundation of coastal regions is recognized as a major threat to people, livelihoods, and the ecosystem health. The assessment of the magnitude of flooding drivers and the flood extension mapping are essential to avoid and reduce the adverse impacts of floods. Attending these issues, the present study aims to assess marine-induced inundation in Ria de Aveiro coastal lagoon under extreme sea levels induced by astronomic tide and storm surge events. The approach followed integrates joint probability analysis of residual and astronomical levels from the lagoon inlet with application of the ELCIRC hydrodynamic model, which was validated for tidal and storm surge conditions. The model is applied under extreme sea levels corresponding to 2- and 100-year return periods of storm surges combined with tidal elevation for the present mean sea level and also considering a mean sea level rise estimate of 0.42 m for both return periods. A mean spring tide was also simulated as the reference case. The maximum levels, the lagoon flooded area and the tidal prism across the lagoon main channels were analysed for all simulations. The application of joint probability analysis of residual and astronomical levels resulted in extreme sea levels between 3.85 and 4.56 m, relative to the local chart datum. The validation results evidence that model reproduces accurately both tidal and storm surge propagation. The lagoon flooded area increased between 22 and 79 % for the most optimistic and pessimistic scenarios, respectively, relatively to the reference tide. The morphological lagoon features (depth of channels and topography of margins) determine the tidal prism and consequently the marginal inundation patterns found. Consequently, the more exposed regions present low altitude and are located at the margins of deeper channels.

Spatial and temporal variation in fish community of the Ria de Aveiro estuarine lagoon (Portugal).

Event Abstract Back to Event Spatial and temporal variation in fish community of the Ria de Aveiro estuarine lagoon (Portugal). Eva García-Seoane1*, Ana Abreu1, Cátia L. Silva1 and José E. Rebelo1 1 University of Aveiro, Department of Biology, Portugal Fish assemblages of Ria de Aveiro coastal lagoon (Northwest Portugal) were studied from February 2012 and January 2013. Sampling were monthly conducted with a traditional beach-seine net (“chincha”) at 9 sites. Multivariate approach were used in order to analyse the spatial and temporal variation in fish community. A total of 58,201 fishes, weighting 249,540 g, were identified, representing 37 taxa and 21 families. Four taxa (Atherina spp., Dicentrarchus labrax, Liza spp., and Sardina pilchardus) were responsible for 94.7% and 85.4% of the total abundance, in number and weight. There were significant differences in fish community, in terms of fish number and weight, between sites and between months (ANOSIM, p<0.01). A total of 12 species appeared as characteristics of one of more sampling sites either in terms of number and weight. In both cases, D. labrax, Liza spp. and Atherina spp. were typical throughout the study area. Other species, such as Spondyliosoma cantharus appeared as typical only in the part of the lagoon more influenced by marine waters, whereas Anguilla anguilla was typical of the inner area. A total of 11 (in number) or 13 (in weight) species appeared as typical of at least one month of the year. Liza spp. and Atherina spp. were typical all the year round for number and weight data. In both cases, D. labrax, Diplodus spp. and S. pilchardus, appeared as a typical from spring to autumn. The number of typical species varied with the season, being maximum in May and minimum in winter. Finally, results of this work were discussed in comparison to previous studies. Acknowledgements We thank the fishermen’s association APARA, all the local fishermen, and the colleagues who assisted in the field sampling. The authors are grateful V. Quintino for providing access to the PRIMER software. This work was supported by “Grupo de Ação Costeira da Região de Aveiro” (GAC-RA) through the projects “Enguias na Ria de Aveiro, um ex-líbris a preservar: biologia, sanidade e pesca” and “Promoção dos Recursos Endógenos da Ria: Conhecer, Usufruir e Preservar”. Keywords: Coastal lagoon, fish assemblage, Portugal, Ria de Aveiro, spatial variations, Seasonal variations. Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Oral Presentation Topic: Ecology, Conservation and Invasive Species Citation: García-Seoane E, Abreu A, Silva CL and Rebelo JE (2015). Spatial and temporal variation in fish community of the Ria de Aveiro estuarine lagoon (Portugal).. Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.fmars.2015.03.00095 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 20 Nov 2015; Published Online: 21 Nov 2015. * Correspondence: Dr. Eva García-Seoane, University of Aveiro, Department of Biology, Aveiro, 3810-193, Portugal, eva.garcia.seoane@hi.no Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Eva García-Seoane Ana Abreu Cátia L Silva José E Rebelo Google Eva García-Seoane Ana Abreu Cátia L Silva José E Rebelo Google Scholar Eva García-Seoane Ana Abreu Cátia L Silva José E Rebelo PubMed Eva García-Seoane Ana Abreu Cátia L Silva José E Rebelo Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Abiotic control modelling of salt marsh sediments respiratory CO2 fluxes: application to increasing temperature scenarios

Sediment microbial communities are responsible for several ecosystem key-processes such as decomposition. However, these communities depend on aerobic respiration making them a source of CO2 to the atmosphere. Since sediments are a known important carbon sink, it becomes important to address the factors that modulate sediment respiration and therefore CO2 efflux to the atmosphere. Therefore, the present work aimed to assess the main factors controlling sediment respiratory activity in salt marshes. Sediment respiration and several sediment abiotic characteristics were assessed in two salt marshes from Ria de Aveiro coastal lagoon with contrasting environmental conditions. Sediment respiration had significant differences across seasons and salt marshes, and different patterns of activity were found for each salt marsh. Statistical analysis and modelling by Generalized Linear Model (GLM) revealed that sediment respiration is mostly influenced by organic matter quality (C:N ratio), sediment temperature and sediment pH. Nevertheless, as temperature appeared to be one of the most important factors influencing CO2 effluxes from the sediments, its influence during possible global warming scenarios was focused. The simulations produced by the GLM using the IPCC scenarios projections, indicated that salt marshes will tend do decrease their CO2 emissions with the increasing temperatures, reinforcing their role as important carbon sinks. This can be interpreted as an ecosystemic counteract measure toward a reduction of the increasing temperature by reducing the amounts of greenhouse gas emissions, namely CO2.