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- Mechanisms of bioinvasions by coastal crabs using integrative approaches – A conceptual reviewPublication . Rato, Lénia D.; Crespo, Daniel; Lemos, Marco F. L.Crustaceans are amongst the most reported invaders of coastal habitats, and predatory brachyuran crabs one of the most successful marine invasive groups. They hold high tolerance to abiotic stress and their genetic, life-history, and behavioural adaptation mechanisms prompt their invasive conspicuousness. However, there is a generalized ambiguity on the specific processes that make these bioinvasions successful. No trait-related patterns have yet been found, mostly since traits attributed solely to non-indigenous crab species lack confirmation by comparison with their native counterparts and across each other. Therefore, this review discusses the available literature on fitness and plasticity of brachyuran crabs under global changes, and advances the increasing importance of addressing native versus non-native invasive species comparisons in the annals of brachyura invasion dynamics. Further on, integrative approaches are highlighted and proposed as innovative tools to disentangle trait-related tolerance, overall crab phenotypic plasticity and further adaptation. These indicator tools will advance the knowledge on crabs’ invasive potential, which ultimately affects upcoming population dynamics and ecosystem services, adding value to an effective management of coastal bioinvasions.
- Study of Temporal Variations in Species–Environment Association through an Innovative Multivariate Method: MixSTATICOPublication . González-Narváez, Mariela; Fernández-Gómez, María José; Mendes, Susana; Molina, José-Luis; Ruiz-Barzola, Omar; Galindo-Villardón, PurificaciónThe study of biotic and abiotic factors and their interrelationships is essential in the preservation of sustainable marine ecosystems and for understanding the impact that climate change can have on different species. For instance, phytoplankton are extremely vulnerable to environmental changes and thus studying the factors involved is important for the species’ conservation. This work examines the relationship between phytoplankton and environmental parameters of the eastern equatorial Pacific, known as one of the most biologically rich regions in the world. For this purpose, a new multivariate method called MixSTATICO has been developed, allowing mixed-type data structured in two different groups (environment and species) to be related and measured on a space–time scale. The results obtained show how seasons have an impact on species–environment relations, with the most significant association occurring in November and the weakest during the month of May (change of season). The species Lauderia borealis, Chaetoceros didymus and Gyrodinium sp. were not observed in the coastal profiles during the dry season at most stations, while during the rainy season, the species Dactyliosolen antarcticus, Proboscia alata and Skeletonema costatum were not detected. Using MixSTATICO, species vulnerable to specific geographical locations and environmental variations were identified, making it possible to establish biological indicators for this region.
- LDAShiny: An R Package for Exploratory Review of Scientific Literature Based on a Bayesian Probabilistic Model and Machine Learning ToolsPublication . De la Hoz-M, Javier; Fernández-Gómez, Mª José; Mendes, SusanaIn this paper we propose an open source application called LDAShiny, which provides a graphical user interface to perform a review of scientific literature using the latent Dirichlet allocation algorithm and machine learning tools in an interactive and easy-to-use way. The procedures implemented are based on familiar approaches to modeling topics such as preprocessing, modeling, and postprocessing. The tool can be used by researchers or analysts who are not familiar with the R environment. We demonstrated the application by reviewing the literature published in the last three decades on the species Oreochromis niloticus. In total we reviewed 6196 abstracts of articles recorded in Scopus. LDAShiny allowed us to create the matrix of terms and documents. In the preprocessing phase it went from 530,143 unique terms to 3268. Thus, with the implemented options the number of unique terms was reduced, as well as the computational needs. The results showed that 14 topics were sufficient to describe the corpus of the example used in the demonstration. We also found that the general research topics on this species were related to growth performance, body weight, heavy metals, genetics and water quality, among others.
- Marine Natural Products as Anticancer AgentsPublication . Alves, Celso; Diederich, MarcCancer remains one of the major threats to human health and one of the deadliest diseases worldwide [1]. Therapy failure and consequent cancer relapse are the main factors contributing to high cancer mortality, making it crucial to find and develop new therapeutic options. Over the last few decades, natural products became one of the key drivers in the drug development of innovative cancer treatments [2]. In opposition to drug development from terrestrial resources, the marine environment only recently emerged as a prolific source of unparalleled structurally active metabolites [3]. Due to their excellent scaffold diversity, structural complexity, and ability to act on multiple cell signaling networks involved in carcinogenesis, marine natural products are ideal candidates to inspire the development of novel anticancer medicines [4,5].
- Ichthyofauna of the Selvagens Islands. Do small coastal areas show high species richness in the northeastern Atlantic?Publication . Almada, Frederico; Abecasis, David; Villegas-Ríos, David; Henriques, Sofia; Pais, Miguel P.; Batista, Marisa; Costa, Bárbara Horta; Martins, Joana; Tojeira, Inês; Rodrigues, Nuno Vasco; Araújo, Ricardo; Souto, Miguel; Alonso, Hany; Falcón, Jesús M.; Henriques, Filipe; Catry, Paulo; Cabral, Henrique; Biscoito, Manuel; Almada, Vitor C.The Selvagens Islands are located in the northeastern Atlantic between the Canary Islands and Madeira Island. As a result of their small size, remote location and harsh sea conditions only a few studies have been conducted to describe their marine species diversity. We were able to identify 29 new coastal fish species, an increase of 33% in the ichthyofauna described for these islands (n = 88). There is a prevalence of species with tropical affinities and only 2.3% (n = 2) are endemic to Macaronesia. Considered a stepping-stone colonization vector from the nearest continental shore, as proposed by other authors for this region, the Selvagens Islands host 34.1% of the ichthyofauna described for the much larger Canary Islands (nspecies = 258, submerged area nSelvagens Is. = 2.3%) and 47.3% of the ichthyofauna described for the more distantly located Madeira Island (nspecies = 186, submerged area nSelvagens Is. = 17.9%). Interestingly, 6.8% (n = 6) of the species failed to bridge the gap between the Selvagens Islands and Madeira Island. Data collected so far showed no trend toward an increasing number of species with high dispersal capability. The Selvagens Islands are an example of a high coastal species diversity occurring even in very small areas of the northeastern Atlantic Ocean.
- Sensitivity of the sea snail Gibbula umbilicalis to mercury exposure – Linking endpoints from different biological organization levelsPublication . Cabecinhas, Adriana S.; Novais, Sara C.; Santos, Sílvia C.; Rodrigues, Andreia C.M.; Pestana, João L.T.; Soares, Amadeu M.V.M.; Lemos, Marco F.L.Mercury contamination is a common phenomenon in the marine environment and for this reason it is important to develop cost-effective and relevant tools to assess its toxic effects on a number of different species. To evaluate the possible effects of Hg in the sea snail Gibbula umbilicalis, animals were exposed to increasing concentrations of the contaminant in the ionic form for 96h. After this exposure period, mortality, feeding and flipping behavior, the activity of the biomarkers glutathione S-transferase, superoxide dismutase, catalase, lactate dehydrogenase and cholinesterase, the levels of lipid peroxidation and cellular energy allocation were measured. After 96h of exposure to the highest Hg concentration (≈LC20), there was a significant inhibition of the cholinesterase activity as well as impairment in the flipping behavior and post-exposure feeding of the snails. Cholinesterase inhibition was correlated with the impairment of behavioral responses also caused by exposure to Hg. These endpoints, including the novel flipping test, revealed sensitivity to Hg and might be used as relevant early warning indicators of prospective effects at higher biological organization levels, making these parameters potential tools for environmental risk assessment. The proposed test species showed sensitivity to Hg and proved to be a suitable and resourceful species to be used in ecotoxicological testing to assess effects of other contaminants in marine ecosystems.
- Optimisation of Alginate Extraction and Characterisation of Polysaccharides from Brown Seaweed from the Portuguese CoastPublication . Mendes, Joana Corrêa; Valente, Joana F. A.; Sousa, Fani; Bernardino, Raul; Bernardino, Susana; Afonso, Clélia; Chagas, BárbaraAlginate is a widely used and versatile biopolymer with an ever-expanding range of applications in the pharmaceutical and biomedical industries. This highlights the importance of developing sustainable and renewable production sources. Conventional extraction methods, although effective, are often energy-intensive and rely on harsh chemicals. In this context, brown algae are a promising alternative due to their abundance and renewability. This study investigated the potential of Saccorhiza polyschides and Sargassum muticum as sources of sodium alginate (SA), thus optimising an extraction process that combines acid treatment with an alkaline step. The extracted biopolymers were characterised using FTIR, H-NMR, STA, SEM/EDX, viscosity measurements, dynamic light scattering, and spectrophotometric assays of residual polyphenols and proteins. The optimised extraction conditions produced yields above 20% of high-purity alginate. When compared with commercial SA, the extracted materials showed comparable quality while relying on a simplified, solvent-reduced protocol that improves process efficiency and reduces the environmental impact. These results demonstrate that S. polyschides and S. muticum are promising, locally available sources of high-quality sodium alginate, and that industrially relevant yields (>20%) can be achieved through an environmentally conscious two-step extraction process.
- The study of bacterioplankton dynamics in the Berlengas Archipelago (West coast of Portugal) using the HJ-biplot methodPublication . Maranhão P.; Mendes, Susana; Fernández-Goméz, M. J.; Galindo-Villardón, M. P.; Azeiteiro, Ulisses; Bacelar-Nicolau, PaulaThe relationship between bacterioplankton and environmental forcing in the Berlengas Archipelago (Western Coast of Portugal) were studied between February 2006 and February 2007 in two sampling stations: Berlenga and Canal, using an HJ-biplot. The HJ-biplot showed a simultaneous display of the three main metabolic groups of bacteria involved in carbon cycling (aerobic heterotrophic bacteria, sulphate-reducing bacteria and nitrate-reducing bacteria) and environmental parameters, in low dimensions. Our results indicated that bacterial dynamics are mainly affected by temporal gradients (seasonal gradients with a clear winter versus summer opposition), and less by the spatial structure (Berlenga and Canal). The yearly variation in the abundance of aerobic heterotrophic bacteria were positively correlated with those in chlorophyll a concentration, whereas ammonium concentration and temperature decreased with increasing phosphates and nitrites concentration. The relationship between aerobic heterotrophic bacteria, chlorophyll a and ammonium reveals that phytoplankton is an important source of organic substrates for bacteria.
- The effect of sewage discharge on Melarhaphe neritoides (Gastropoda: Littorinidae) population dynamicsPublication . Cabral-Oliveira, J.; Maranhão, Paulo; Pardal, M. Â.The discharges of sewage effluent treatment plants has a major impact on coastal communities. In our study area (western coast of Portugal) Melarhaphe neritoides (L. 1758) is the dominant high-shore gastropod. Two populations of M. neritoides were studied in order to understand the impact of sewage discharges on intertidal communities: one popula tion in an impacted area and the other in a similar but unimpacted area (reference site). Environmental data and abundance, biomass, population structure and annual growth production of M. neritoides were estimated in the two areas. The results showed that M. neritoides density is higher in the impacted area as a result of massive settlement. The sewage discharge increases the nutrient concentrations in the water, which causes more microalgae to grow on the rocky surfaces. This higher availability of food may promote recruitment. However, we found high mortality in the juveniles in the impacted area, which affected density values on the upper shore levels (where we found the adults) of both areas. Moreover, the adults were bigger in the unimpacted area, which suggests that individuals grow more or live longer in this area.
- Fish diversity in the Berlengas Natural Reserve (Portugal), a marine protected areaPublication . Maranhão, Paulo; Vasco Rodrigues, Nuno; Mendes, Susana; Franco, João; Castanheira, Maria; Castro, NunoSince 1981, Berlengas, an archipelago located about 7 miles off Peniche (Western Coast of Portugal), became a marine protected area. Underwater visual census, namely rover diver counts, were used to assess the fish species present in the area during two summer campaigns, 2004 and 2005, comprising a total of 16 hours of scuba diving observations. This study aimed to obtain a more accurate and detailed checklist of the fish species present in the archipelago than the one already existing in result of a few previous studies. A total of 48 fish species belonging to 22 different families were observed during the two study periods. Labridae and Sparidae were the most represented families and Diplodus vulgaris and Labrus bergylta were the most frequent species.