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- Sand smelt ability to cope and recover from ocean's elevated CO 2 levelsPublication . Silva, Cátia S. E.; Lemos, Marco F. L.; Faria, Ana M.; Lopes, Ana F.; Mendes, Susana; Gonçalves, Emanuel J.; Novais, Sara C.Considered a major environmental concern, ocean acidification has induced a recent research boost into effects on marine biodiversity and possible ecological, physiological, and behavioural impacts. Although the majority of literature indicate negative effects of future acidification scenarios, most studies are conducted for just a few days or weeks, which may be insufficient to detect the capacity of an organism to adjust to environmental changes through phenotypic plasticity. Here, the effects and the capacity of sand smelt larvae Atherina presbyter to cope and recover (through a treatment combination strategy) from short (15 days) and long-term exposure (45 days) to increasing pCO2 levels (control: ~515 μatm, pH = 8.07; medium: ~940 μatm, pH = 7.84; high: ~1500 μatm, pH = 7.66) were measured, addressing larval development traits, behavioural lateralization, and biochemical biomarkers related with oxidative stress and damage, and energy metabolism and reserves. Although behavioural lateralization was not affected by high pCO2 exposure, morphometric changes, energetic costs, and oxidative stress damage were impacted differently through different exposures periods. Generally, short-time exposures led to different responses to either medium or high pCO2 levels (e.g. development, cellular metabolism, or damage), while on the long-term the response patterns tend to become similar between them, with both acidification scenarios inducing DNA damage and tending to lower growth rates. Additionally, when organisms were transferred to lower acidified condition, they were not able to recover from the mentioned DNA damage impacts. Overall, results suggest that exposure to future ocean acidification scenarios can induce sublethal effects on early life-stages of fish, but effects are dependent on duration of exposure, and are likely not reversible. Furthermore, to improve our understanding on species sensitivity and adaptation strategies, results reinforce the need to use multiple biological endpoints when assessing the effects of ocean acidification on marine organisms.
- Response surface methodology in the optimization of extraction conditions for Gracilaria gracilis extracts for use in thermoplastic food coatingsPublication . Reboleira, João; Andrade, Mariana A.; Sanches-Silva, Ana; Ganhão, Rui; Mendes, Susana; Vilarinho, Fernanda; Félix, Rafael; Pinheiro, Joaquina; Bernardino, Susana M.Incorporation of antioxidant agents in edible films and packages often relies in the usage of essential oils and other concentrated hydrophobic liquids, with reliable increases in antimicrobial and antioxidant activities of the overall composite, and consequent improvements in product shelf life. These oils are often obtained from plant sources and the usage of organic solvents in their extraction has been criticized as to whether it constitutes a health hazard for consumers [1, 2, 3]. The use of water-soluble antioxidant agents is less common, due to lower activities and extraction yields. As such, using commonly available seaweeds as the source for both the main polymers and the supplementing antioxidant/antimicrobial agents in bioactive films can potentially reduce production costs and create a safer, more sustainable product [1]. Hydroethanolic extracts of commercially available red macroalgae Gracilaria gracilis were evaluated for their antioxidant potential and phenolic content, as part of the preliminary assays for the selection of algal biomass for the enrichment of thermoplastic films. The extracts were obtained through use of solid-liquid extractions, over which yield, DPPH radical reduction capacity, total phenolic content, and FRAP activity assays were measured [4, 5]. Solid to liquid ratio (SLR), extraction time, and ethanol to water ratio were selected as independent variables with experimental ranges and configurations obtained using a Box-Behnken design with three factors, resulting in 15 experimental conditions. Extraction duplicates were used [4]. Response surface methodology was then used to estimate the effect of each extraction condition on the tested bioactivities. Bioactivities were significantly (p<0.05) and positively affected by the presence of ethanol in the extraction solvent, while extraction yield was reduced. Lower solid to liquid ratios (higher solvent proportions) resulted in higher yields, but had no significant (p<0.05) impact on bioactivities. Time was not a relevant factor in any of the measured variables, and as such will be minimized in any further work. 100% ethanol with minimum extraction time (10 minutes) and 1g to 5mL SLR maximize antioxidant activities per gram of dry extract. Maximum ethanolic yields were obtained with a theoretical extraction of 100 minutes and a 1g to 25mL SLR. Aqueous extractions displayed similar results in terms of optimum conditions, but with overall lower bioactivities and higher yields, very likely due to high amounts of soluble polysaccharides. While the high antioxidant activities from the ethanolic extracts encourage the selection of this solvent for extraction of bioactives, low yields may make them later unfeasible. Future studies over the compatibility of these extracts in the polymeric matrix of the films, as well as further optimization of the extraction process will be necessary before the definitive choice for bioactive origin and processing is made.
- Stability, kinetics, and application study of phycobiliprotein pigments extracted from red algae Gracilaria gracilisPublication . Pereira, Tatiana; Barroso, Sonia; Mendes, Susana; Gil, Maria M.Phycobiliprotein (PBP) pigments were extracted from red algae Gracilaria gracilis through maceration in phosphate buffer using previously optimized conditions. The stability of PBPs in the extracts was assessed by monitoring the extracts at different pHs and temperatures for 10 days. Since phycoerythrin (PE) is the main PBP present in G. gracilis, PE content was spectroscopically determined and used as a response factor. Kinetic modeling was used to describe PE degradation under different ranges of T and pH. The pigment extracts presented higher stability at pH 6.9 and −20 °C. PE was semipurified by precipitation with ammonium sulphate 65% followed by dialysis against water until a purity index of 0.7. The pigment was successfully applied as colorant in pancakes and yogurts with a pigment concentration of 0.15%. This study highlights the potential of PE pigments extracted from G. gracilis for applications in food products.
- Portuguese commercial fisheries of swordfish, Xiphias gladiusPublication . Roxo, André; Mendes, Susana; Correia, JoãoSwordfish (Xiphias gladius) plays an important role in Portuguese fisheries. Portuguese commercial swordfish landings were analyzed from 1986 to 2012. Commercial landings of five incidental catches of pelagic sharks—bigeye thresher shark (Alopias superciliosus), thresher shark (Alopias vulpinus), shortfin mako shark (Isurus oxyrinchus), blue shark (Prionace glauca), and smooth hammerhead shark (Sphyrna zygaena)—were also evaluated for the same period. A total of 653 landings of swordfish (12,625 t) were observed in 62 ports. Annual landings for the fishery generally decreased over time, with a corresponding increase in price per kilogram. The most fished shark was blue shark, with 12,715 t in 48 ports. It was followed by shortfin mako, thresher, smooth hammerhead, and bigeye thresher (with 5113 t, 672 t, 19 t, and 0.45 t, respectively). Lowest landings of swordfish were observed in the first semester of each year, while catch levels of blue sharks were high during the same period. Shortfin mako catches did not raise until 2005. The remaining species studied always displayed lower landings, suggesting that most of them are bycaught.
- O contributo das redes sociais para o desenvolvimento das Casas de Fado em AlfamaPublication . Simões, Sofia; Mendes, Susana; Carvalho, MárioOs turistas atualmente preferem o uso da internet e das redes sociais para pesquisar informações. O dinamismo dessas redes é uma ferramenta atrativa e de fácil utilização para os turistas. As redes sociais podem ser por isso um fator decisivo para influenciar as escolhas de acordo com a motivação dos turistas. O Fado, para além de ser uma marca de elevada notoriedade, assune-se também como o embaixador de excelência para o reforço da marca Portugal além-fronteiras. Este trabalho de investigação procura entender o contributo das redes sociais para o desenvolvimento das Casas do Fado em Alfama (Lisboa). Foi ainda estudada a intenção dos turistas em compartilhar as suas experiências nas redes sociais. Este trabalho foi estruturado em duas partes: revisão da literatura (1) e a aplicação de uma pesquisa (2) em várias Casas do Fado em Alfama. Assim, a pesquisa (n = 532) procurou perceber se os turistas quando frequentam as Casas de Fado utilizam as redes sociais para compartilhar as suas experiências. Os resultados expuseram algumas lacunas, nomeadamente evidenciaram a importância dos clientes partilharem as suas experiencias contribuindo assim para o aumento da promoção das Casas de Fado. Foi ainda possível observar o potencial das redes sociais para a criação de estratégias potenciando o desenvolvimento das Casas de Fado em Alfama.
- Zooplankton distribution in a marine protected area: The Berlengas Natural Reserve, Western Coast of PortugalPublication . Mendes, Susana; Marques, Sónia Cotrim; Azeiteiro, Ulisses Miranda; Fernández-Gómez, Mª José; Galindo-Villardón, Mª Purificación; Maranhão, Paulo; Morgado, Fernando; Leandro, Sérgio MiguelZooplankton distribution in the Berlengas Natural Reserve (Portugal) was studied over a period of one year (February 2006 to February 2007). Monthly sampling was performed at 6 stations, differentiated according to depth and distance to the coastline. The aim of this study was to investigate the overall zooplankton variability through its different dimensions (space vs. time). The Partial Triadic Analysis (PTA) was used to study the spatial variability of the zooplankton community and its dynamics in time and the dynamic trajectories of the zooplankton species for each site. It was possible to distinguish a neritic-ocean gradient of the zooplankton composition and a temporal variability. Four distinct periods can be highlighted considering the distribution of the dates and the arrangement of the species: (i) the first one comprised August to November, (ii) the second one was related to June and July, (iii) the third one associated with spring (April and May) and, (iv) the latest one was related to winter (February, March and December 2006 and January and February 2007). The PTA method showed the similarities between the successive data tables and proved to be useful for investigating biotic structures and detecting spatial-temporal patterns in zooplankton distribution.
- Modelling fish growth with imperfect data: The case of Trachurus picturatusPublication . Neves, Ana; Vieira, Ana Rita; Sequeira, Vera; Silva, Elisabete; Silva, Frederica; Duarte, Ana Marta; Mendes, Susana; Ganhão, Rui; Assis, Carlos; Rebelo, Rui; Magalhães, Maria Filomena; Gil, Maria Manuel; Gordo, Leonel SerranoGrowth modelling is essential to inform fisheries management but is often hampered by sampling biases and imperfect data. Additional methods such as interpolating data through backcalculation may be used to account for sampling bias but are often complex and time-consuming. Here, we present an approach to improve plausibility in growth estimates when small individuals are under-sampled, based on Bayesian fitting growth models using Markov Chain Monte Carlo (MCMC) with informative priors on growth parameters. Focusing on the blue jack mackerel, Trachurus picturatus, which is an important commercial fish in the southern northeast Atlantic, this Bayesian approach was evaluated in relation to standard growth model fitting methods, using both direct readings and back-calculation data. Matched growth parameter estimates were obtained with the von Bertalanffy growth function applied to back-calculated length at age and the Bayesian fitting, using MCMC to direct age readings, with both outperforming all other methods assessed. These results indicate that Bayesian inference may be a powerful addition in growth modelling using imperfect data and should be considered further in age and growth studies, provided relevant biological information can be gathered and included in the analyses.
- Optimization of phycobiliprotein pigments extraction from red algae Gracilaria gracilis for substitution of synthetic food colorantsPublication . Pereira, Tatiana; Barroso, Sónia; Mendes, Susana; Amaral, Renata A.; Dias, Juliana R.; Baptista, Teresa; Saraiva, Jorge A.; Alves, Nuno; Gil, Maria M.The extraction of phycobiliprotein (PBP) pigments from red algae Gracilaria gracilis was optimized using maceration, ultrasound-assisted extraction (ultrasonic water bath and ultrasonic probe), high pressure-assisted extraction, and freeze-thaw. The experimental conditions, namely homogenization time (t1), buffer concentration (C), treatment time (t2), biomass: buffer ratio (R), and pressure (P), were optimized using Response Surface Methodology (RSM). The yield of phycoerythrin (PE) extracted, determined spectroscopically, was used as the response variable. Maceration was the most efficient extraction method yielding 3.6 mg PE/g biomass under the optimal conditions (t1 = t2 = 10 min; C = 0.1 M; R = 1:50). Scanning Electron Microscopy (SEM) analysis of the biomass before and after the cell disruption treatments revealed a more efficient cell wall rupture with maceration.
- Effect of different drying temperatures on the moisture, content of phytochemical constituents and technological properties of Peniche coast seaweedsPublication . Augusto, Ana; Nunes, Paulo M.; Mendes, Susana; Afonso, Clélia; Mouga, Teresa
- Faecal indicator bacteria and Pseudomonas aeruginosa in marine coastal waters: is there a relationship?Publication . Januário, Adriana P.; Afonso, Clélia; Mendes, Susana; Rodrigues, Maria J.To estimate the quality of coastal waters, European Union Directive 2006/7/EC provides guidelines to assess levels of faecal bacteria, including Escherichia coli and intestinal enterococci. These microbiological criteria are based on studies that determine the risk of bathers having diseases caused by enteric bacteria, not necessarily measuring the potential danger associated with the presence of nonenteric pathogens. The association between the presence of faecal contaminant indicators and nonenteric pathogenic microorganisms has not been well defined yet. The purpose of this study is to establish a relationship between Pseudomonas aeruginosa and microbiological indicators of faecal contamination. Presence of microbiological contamination in the coastal waters near the sewage treatment plant (STP) of Peniche (Portugal) was confirmed (P. aeruginosa 135.8 Colony Forming Unit/100 mL, Escherichia coli 1100.1 Most Probable Number/100 mL, intestinal enterococci 2685.9 MPN/100 mL) with much lower levels in the areas located south of the STP, along the main water coastal current (beach 1: 0.7 CFU/100 mL, 16.5 MPN/100 mL, 100.5 MPN/100 mL; beach 2: 0.3 CFU/100 mL, 74.0 MPN/100 mL, 145.9 MPN/100 mL, respectively). Analysis of Pearson’s correlation revealed a strong positive correlation between E. coli and P. aeruginosa, suggesting E. coli as an indicator of P. aeruginosa presence.