Browsing by Author "Gameiro, Carla"
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- Changes in the Phytoplankton Composition in a Temperate Estuarine System (1960 to 2010)Publication . C. Brito, Ana; Moita, Teresa; Gameiro, Carla; Silva, Teresa; Anselmo, Tânia; Brotas, VandaThe main aim of this study was to evaluate the temporal changes in the phytoplankton community of the Tagus Estuary and to identify the stressors involved. Environmental and phytoplankton data were gathered from several studies conducted in the 1960s, 1980s and from 1999 to 2010 (2000s). Phytoplankton data included information on the community composition through microscopy. No significant change was found between temperature and nitrogen values in the three periods. Chlorophyll a concentrations varied throughout the years, and the lowest concentrations were observed after 2004. Significant differences were also found between phytoplankton cell abundances, lower in the 1980s compared to the ones recorded in the 2000s. In the 1980s, diatoms were the most abundant group in the majority of samples and were found to be associated with nitrogen concentrations (canonical correspondence analysis), which was not observed in the 2000s. In the period 2006–2007, the importance of diatoms decreased and smaller cells became more abundant (e.g. cryptophytes, euglenophytes, prasinophytes). The ratio cryptophyta/bacillariophyta seems to yield an increase from <1 in 1980s to >1 in 2006–2007. Mesodinium rubrum and Dinophysis produce recurrent toxic blooms in the adjacent coastal area. We can speculate that the estuary can be a cryptophyte producer to sustain the cryptophytes-M. rubrum-Dinophysis trophic relationship. A top-down hypothesis (shellfish grazing) is considered to explain the change in the phytoplankton community. A quantitative tool, the Phytoplankton Community Index (PCI), yielded a significant deviation of the community, from the 1980s to the 2000s, suggesting a shift toward the dominance of small cells.
- Characterisation of estuarine intertidal macroalgae by laser-induced fluorescencePublication . Gameiro, Carla; Utkin, Andrei B.; Cartaxana, PauloThe article reports the application of laser-induced fluorescence (LIF) for the assessment of macroalgae communities of estuarine intertidal areas. The method was applied for the characterisation of fifteen intertidal macroalgae species of the Tagus estuary, Portugal, and adjacent coastal area. Three bands characterised the LIF spectra of red macroalgae with emission maxima in the ranges 577–583 nm, 621–642 nm and 705–731 nm. Green and brown macroalgae showed one emission maximum in the red region (687–690 nm) and/or one in the far-red region (726–732 nm). Characteristics of LIF emission spectra were determined by differences in the main fluorescing pigments: phycoerythrin, phycocyanin and chlorophyll a (Chl a). In the green and brown macroalgae groups, the relative significance of the two emission maxima seems to be related to the thickness of the photosynthetic layer. In thick macroalgae, like Codium tomentosum or Fucus vesiculosus, the contribution of the far-red emission fluorescence peak was more significant, most probably due to re-absorption of the emitted red Chl a fluorescence within the dense photosynthetic layer. Similarly, an increase in the number of layers of the thin-blade green macroalgae Ulva rigida caused a shift to longer wavelengths of the red emission maximum and the development of a fluorescence peak at the far-red region. Water loss from Ulva's algal tissue also led to a decrease in the red/far-red Chl fluorescence ratio (F685/F735), indicating an increase in the density of chloroplasts in the shrinking macroalgal tissue during low tide exposure.
- Disentangling the photochemical salinity tolerance in Aster tripolium L.: connecting biophysical traits with changes in fatty acid compositionPublication . Duarte, Bernardo; Cabrita, M. T.; Gameiro, Carla; Matos, A. R.; Godinho, R.; Marques, J. C.; Caçador, IsabelA profound analysis of A. tripolium photochemical traits under salinity exposure is lacking in the literature, with very few references focusing on its fatty acid profile role in photophysiology. To address this, the deep photochemical processes were evaluated by Pulse Amplitude Modulated (PAM) Fluorometry coupled with a discrimination of its leaf fatty acid profile. Plants exposed to 125-250 mm NaCl showed higher photochemical light harvesting efficiencies and lower energy dissipation rates. under higher NaCl exposure, there is evident damage of the oxygen evolving complexes (OECs). On the other hand, Reaction Centre (RC) closure net rate and density increased, improving the energy fluxes entering the PS II, in spite of the high amounts of energy dissipated and the loss of PS II antennae connectivity. Energy dissipation was mainly achieved through the auroxanthin pathway. Total fatty acid content displayed a similar trend, being also higher under 125-250 mm NaCl with high levels of omega-3 and omega-6 fatty acids. The increase in oleic acid and palmitic acid allows the maintenance of the good functioning of the PS II. Also relevant was the high concentration of chloroplastic C16:1t in the individuals subjected to 125-250 mm NaCl, related with a higher electron transport activity and with the organization of the Light Harvesting Complexes (LHC) and thus reducing the activation of energy dissipation mechanisms. All these new insights shed some light not only on the photophysiology of this potential cash-crop, but also highlight its important saline agriculture applications of this species as forage and potential source of essential fatty acids.
- First screening of biocides, persistent organic pollutants, pharmaceutical and personal care products in Antarctic phytoplankton from Deception Island by FT-ICR-MSPublication . Duarte, Bernardo; Gameiro, Carla; Matos, Ana Rita; Figueiredo, Andreia; Silva, Marta Sousa; Cordeiro, Carlos; Caçador, Isabel; Reis-Santos, Patrick; Fonseca, Vanessa; Cabrita, Maria TeresaIn recent years, the Antarctic territory has seen a rise in the number of tourists and scientists. This has led to an increase in the anthropogenic footprint in Antarctic ecosystems, namely in terms of emerging contaminants, such as Biocides, Persistent Organic Pollutants (POPs) as well as Pharmaceutical and Personal Care Products (PPCPs). Yet scarce information on the presence of these emerging contaminants is available for trophic compartments, especially the phytoplankton community. Using high resolution Fourier-transform ion cyclotron-resonance mass spectrometry (FT-ICR-MS), an untargeted screening of the metabolome of the phytoplankton community was performed. Seventy different contaminant compounds were found to be present in phytoplankton collected at two sites in Port Foster Bay at Deception Island. These emerging contaminants included 1 polycyclic aromatic hydrocarbon (PAH), 10 biocides (acaricides, fungicides, herbicides, insecticides and nematicides), 11 POPs (flame retardants, paints and dyes, polychlorinated biphenyl (PCB), phthalates and plastic components), 5 PCPs (cosmetic, detergents and dietary compounds), 40 pharmaceutical compounds and 3 illicit drugs. Pharmaceutical compounds were, by far, the largest group of emerging contaminants found in phytoplankton cells (anticonvulsants, antihypertensives and beta-blockers, antibiotics, analgesic and anti-inflammatory drugs). The detection of several of these potentially toxic compounds at the basis of the marine food web has potentially severe impacts for the whole ecosystem trophic structure. Additionally, the present findings also point out that the guidelines proposed by the Antarctic Treaty and Protocol on Environmental Protection to the Antarctic Treaty should be revisited to avoid the proliferation of these and other PPCPs in such sensitive environments.
- Fitoplâncton do estuário do Tejo (Portugal) : dinâmica sazonal, interanual e produção primáriaPublication . Gameiro, Carla; Brotas, Vanda, 1958-Disponível no documento
- Heat wave impacts on the model diatom Phaeodactylum tricornutum: searching for photochemical and fatty acid biomarkers of thermal stressPublication . Feijão, Eduardo; Gameiro, Carla; Franzitta, Marco; Duarte, Bernardo; Caçador, Isabel; Cabrita, Maria Teresa; Matos, Ana RitaGlobal warming is increasing the frequency and intensity of extreme thermal events, with inevitable consequences for marine ecosystems and organisms. Phytoplankton is at the base of marine food webs and diatoms are major contributors to global primary production. Therefore, environmental changes, such as heat, influencing growth, physiology and biochemical composition of diatoms, impact other organisms at higher trophic levels. The model diatom Phaeodactylum tricornutum, particularly rich in the long chain omega-3 eicosapentaenoic acid (EPA), and able to accumulate substantial amounts of storage lipids, has recently been the object of numerous works, regarding fundamental aspects of lipid metabolism and exploring its biotechnological potential for biodiesel and aquaculture purposes. The aim of this study was to use P. tricornutum, growing under controlled conditions, to examine the effects of a heat wave, in order to identify heat stress biomarkers. The photosynthetic and respiratory metabolism was investigated by Chlorophyll a fluorescence and by O2 evolution and discussed in connection with changes observed in the composition of photosynthetic pigments and fatty acids. Phaeodactylum tricornutum cells exposed to 26 °C displayed lower photosynthetic O2 production, but similar respiratory rate, comparing to cells at control temperature (18 °C), which is likely related to the biomass decrease observed under heat stress. Heat wave exposed cells also showed a less efficient PSII, higher energy dissipation and higher chlorophyll a and fucoxanthin concentrations, suggesting a heat-induced amplification of the light energy absorption capacity. Heat wave exposed cells showed lower relative EPA contents and double bond indexes, whereas the parameter inversely related to nutritional value, omega 6/omega 3 ratio, increased. Moreover, the analysis of the fatty acid profiles also suggested that heat exposure negatively impacted thylakoid lipids, in agreement with the decrease observed in photosynthesis. Results obtained highlight the negative impact of heat waves on diatom photosynthesis and nutritional value, as well as on their capacity to oxygenate ocean water. Furthermore, physiological parameters as well as fatty acids and photosynthetic pigments signatures, were identified, that could represent expedite biomarkers of thermal stress in future studies.
- Integrating In Situ and Ocean Color Data to Evaluate Ecological Quality under the Water Framework DirectivePublication . Brito, Ana C.; Garrido-Amador, Paloma; Gameiro, Carla; Nogueira, Marta; Moita, Maria Teresa; Cabrita, Maria TeresaThe Water Framework Directive (WFD) aims at evaluating the ecological status of European coastal water bodies (CWBs). This is a rather complex task and first requires the use of long-term databases to assess the effect of anthropogenic pressure on biological communities. An in situ dataset was assembled using concomitant biological, i.e., chlorophyll a (Chl a) and environmental data, covering the years from 1995 to 2014, to enable a comprehensive assessment of eutrophication in the Western Iberia Coast (WIC). Given the temporal gaps in the dataset, especially in terms of Chl a, satellite observations were used to complement it. Positive relationships between Chl a 90th percentile and nitrogen concentrations were obtained. The Land-Uses Simplified Index (LUSI), as a pressure indicator, showed no relationship with Chl a, except in Galicia, but it highlighted a higher continental pressure in the Portuguese CWBs in comparison with Galician waters. In general terms, the trophic index (TRIX) showed that none of the CWBs were in degraded conditions. Nevertheless, the relatively high TRIX and LUSI values obtained for the water body in front of Tagus estuary suggest that this area should be subject to continued monitoring. Results highlighted the usefulness of satellite data in water quality assessments and set the background levels for the implementation of operational monitoring based on satellite Chl a. In the future, low uncertainty and harmonized satellite products across countries should be provided. Moreover, the assessment of satellite-based eutrophication indicators should also include metrics on phytoplankton phenology and community structure
- Marine heat waves alter gene expression of key enzymes of membrane and storage lipids metabolism in Phaeodactylum tricornutumPublication . Feijão, Eduardo; Franzitta, Marco; Cabrita, Maria Teresa; Caçador, Isabel; Duarte, Bernardo; Gameiro, Carla; Matos, Ana RitaAcross the globe, heat waves are getting more intense and frequent. Diatoms are a major group of microalgae at the base of the marine food webs and an important source of long chain polyunsaturated fatty acids that are transferred through the food web. The present study investigates the possible impacts of temperature increase on lipid classes and expression of genes encoding enzymes related to lipid metabolism in Phaeodactylum tricornutum. The heat wave exposure caused an increase in the relative amounts of plastidial lipids such as the glycolipids monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and sulphoquinovosyldiacylglycerol (SQDG) in parallel with a decrease in the neutral lipid fraction, which includes triacylglycerols. In agreement, gene expression analyses revealed an up-regulation of a gene encoding one MGDG synthase and down-regulation of a diacylglycerol acyltransferase (DGAT), a key enzyme in triacylglycerol synthesis. Our results show that heat waves not only negatively impact the abundance of unsaturated fatty acids such as eicosapentaenoic acid (20:5n-3, EPA) and hexadecatrienoic acid (16:3n-4) as observed by the decrease in their relative abundance in MGDG and neutral lipids, respectively, but also induce changes in the relative amounts of the diverse membrane lipids as well as the proportion of membrane/storage lipids. The expression study of key genes indicates that some of the aforementioned alterations are regulated at the transcription level whereas others appear to be post-transcriptional. The changes observed in plastidial lipids are related to negative impacts on the photosynthesis.
- Marine microbial community taxonomic and functional indicators to volcanic and anthropogenic stressors in Deception Island, AntarcticaPublication . Duarte, Bernardo; Cruz-Silva, Ana; Feijão, Eduardo; Pereira, Marcelo; Nunes, Mónica; Figueiredo, Andreia; Matos, Ana Rita; Dias, Ricardo; Fonseca, Vanessa; Gameiro, Carla; Cabrita, Maria TeresaIn recent years, the growth in Antarctic tourism has stimulated research on the anthropogenic impacts on the region, boosted by advances in OMIC technologies applied to polar microbial communities. This study aimed to assess the human impacts on marine prokaryotic and viral communities of Deception Island by identifying potential taxonomic, functional, and resistome indicators of both anthropogenic and natural/volcanic pressures. Proteobacteria, Bacteroidetes, and Actinobacteria were the dominant phyla, with notable variations attributed to volcanic activity and anthropogenic pressure. The abundance of Euryarchaeota in regions with increased volcanic activity underlines their adaptability to extreme conditions. Their mercury resistance coupled with their ability to cope with toxic heavy metals is a critical component in managing volcanic mercury concentrations. Actinobacteria, Cyanobacteria, Planctomycetes, and Synergistetes showed distinctive abundance patterns with potential ecological implications related to volcanic environments. Functional analyses revealed the enrichment of functions associated with metal-based, hydrocarbon degradation, and nitrogen metabolism. Submarine volcanic vents contributed significantly to the shape of functional diversity. Identification of specific functions related to nosocomial infections and gastroenteritis highlights the impact of anthropogenic activities on functional traits. Antibiotic resistance genes (ARGs) showed nuanced patterns influenced by both anthropogenic pressure and volcanic activity. Actinobacteria were correlated with increased ARG abundance, which was enhanced by wastewater disposal. Remarkably, Fumarole Bay showed an increased prevalence of certain ARGs, despite a lower anthropogenic impact, suggesting a unique selective pressure induced by volcanic activity. The responsiveness of these indicators to varying levels of pressure characterizes them as valuable tools for assessing and mitigating anthropogenic impacts on the marine waters of Deception Island.
- Marine microbial community taxonomic and functional indicators to volcanic and anthropogenic stressors in Deception Island, AntarcticaPublication . Duarte, Bernardo; Cruz-Silva, Ana; Feijão, Eduardo; Pereira, Marcelo; Nunes, Mónica; Figueiredo, Andreia; Matos, Ana Rita; Dias, Ricardo; Fonseca, Vanessa; Gameiro, Carla; Cabrita, Maria TeresaIn recent years, the growth in Antarctic tourism has stimulated research on the anthropogenic impacts on the region, boosted by advances in OMIC technologies applied to polar microbial communities. This study aimed to assess the human impacts on marine prokaryotic and viral communities of Deception Island by identifying potential taxonomic, functional, and resistome indicators of both anthropogenic and natural/volcanic pressures. Proteobacteria, Bacteroidetes, and Actinobacteria were the dominant phyla, with notable variations attributed to volcanic activity and anthropogenic pressure. The abundance of Euryarchaeota in regions with increased volcanic activity underlines their adaptability to extreme conditions. Their mercury resistance coupled with their ability to cope with toxic heavy metals is a critical component in managing volcanic mercury concentrations. Actinobacteria, Cyanobacteria, Planctomycetes, and Synergistetes showed distinctive abundance patterns with potential ecological implications related to volcanic environments. Functional analyses revealed the enrichment of functions associated with metal-based, hydrocarbon degradation, and nitrogen metabolism. Submarine volcanic vents contributed significantly to the shape of functional diversity. Identification of specific functions related to nosocomial infections and gastroenteritis highlights the impact of anthropogenic activities on functional traits. Antibiotic resistance genes (ARGs) showed nuanced patterns influenced by both anthropogenic pressure and volcanic activity. Actinobacteria were correlated with increased ARG abundance, which was enhanced by wastewater disposal. Remarkably, Fumarole Bay showed an increased prevalence of certain ARGs, despite a lower anthropogenic impact, suggesting a unique selective pressure induced by volcanic activity. The responsiveness of these indicators to varying levels of pressure characterizes them as valuable tools for assessing and mitigating anthropogenic impacts on the marine waters of Deception Island.