Publications by authors named "Miguel Pardal"

Article Synopsis
  • The study investigates the impact of SARS-CoV-2 on the presence and behavior of JC Virus and Norovirus in municipal wastewater, using samples collected in 2020.
  • It finds that JC Virus is consistently present in wastewater, indicating transmission through urine, while Norovirus shows changes with different detection rates before and after SARS-CoV-2 appeared.
  • The results highlight the inefficiency of the wastewater treatment plant in removing viruses, which raises concerns about tracking viral disease outbreaks based on effluent data.
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Several invasive species can occupy the same geographic area. Interaction between species depends on several factors, and the results of such interactions can be highly diverse. Asparagopsis armata is a invasive red seaweed whose exudates contain a cocktail of toxic halogenated compounds.

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  • The study analyzes how the North Atlantic Oscillation (NAO) affects regional climate, hydrology, and sea surface temperatures, specifically looking at decapod larval communities from 2003 to 2012 in Portugal's Mondego Estuary.
  • Research found that sea surface temperature changes significantly influenced the abundance and diversity of key decapod larvae like Carcinus maenas and Diogenes pugilator, especially after notable environmental shifts in 2007.
  • Although water temperature was crucial for the larval communities, the rate of Marine Heatwaves (MHW) events did not show a significant impact on these populations, raising concerns about how ongoing climate change may affect these important marine organisms.
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The present study validates the potential of the in vitro H9c2(2-1) cell-based sulforhodamine B (SRB) assay to evaluate the temporal variability of wastewater quality. The impact of effluent disposal on water quality and the efficiency of the wastewater treatment process were also assessed. To correlate standard analytical method results with in vitro results, a total of 16 physicochemical parameters, such as nutrients, pH, chemical oxygen demand, total suspended solids and metals, were determined in both raw and treated wastewater samples.

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A seasonal characterization of mercury (Hg) accumulation in three different estuaries along the Portuguese coast (i.e. Ria de Aveiro, Tagus estuary and Ria Formosa) was done.

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Estuaries are among the most valuable aquatic systems in the world and resolving how there are impacted by climate change is fundamental to their management under global change scenarios. In this study, a ten-year time series (2003-2013) of zooplankton in an estuarine area (Mondego estuary, Portugal) is used to determine the impact of climate variability on estuarine zooplanktonic secondary production. For that, a trend analysis of seasonal zooplankton production was applied and their link with large-scale, regional, and local environment was tested by Distance-based multivariate multiple regression (DistLM).

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Article Synopsis
  • Seaweeds are increasingly recognized for their value across various sectors, including food, cosmetics, and pharmaceuticals, due to their rich nutritional profile and beneficial compounds.
  • However, the harvest and cultivation of algae carry potential hazards, such as the accumulation of pharmaceuticals from their environments, making safety monitoring crucial for both human and environmental health.
  • This study presents a validated analytical method using ultra-high-performance liquid chromatography coupled with time-of-flight mass spectrometry (UHPLC-ToF-MS) to detect and confirm 62 pharmaceuticals across 8 therapeutic classes in seaweeds.
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Understanding the long-term effects of climatic factors on key species' recruitment is crucial to species management and conservation. Here, we analysed the recruitment variability of key species (Dicentrarchus labrax, Platichthys flesus, Solea solea, Pomatoschistus microps and Pomatoschistus minutus) in an estuary between 2003 and 2019, and related it with the prevailing local and large-scale environmental factors. Using a dynamic factor analysis (DFA), juvenile abundance data were grouped into three common trends linked to different habitat uses and life cycle characteristics, with significant effect of temperature-related variables on fish recruitment: Sea surface temperature and the Atlantic Multidecadal Oscillation.

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Early life phenology is a crucial factor for population dynamics in a climate change scenario. As such, understanding how the early life cycle of marine fishes is influenced by key oceanic and climate drivers is of chief importance for sustainable fisheries. This study documents interannual changes in early life phenology of two commercial flatfishes: European flounder (Platichthys flesus) and common sole (Solea solea) from 2010 to 2015 based on otolith microstructure.

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The main goal of the present study is to determine the sources of methylmercury (MeHg) for high fish-consumption populations with the Portuguese population as showcase, as Portugal is the EU country with the highest fish consumption per capita (2019: 59.91 kg year). Since limited information is available on the effective levels of mercury after culinary treatments, cooked and raw codfish (Gadus morhua), hake (Merluccius merluccius), octopus (Octopus vulgaris), horse mackerel (Trachurus trachurus) and sardine (Sardina pilchardus) were considered.

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Neurotransmitters modulate gonadal maturation in bivalves. However, it remains unclear whether there are differences in the nervous system structure between sexes, maturation, and ganglia. Therefore, a stereological study was conducted on the ganglia of adult peppery furrow shell ().

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It is well-known that climate change significantly impacts ecosystems (at the macro-level) and individual species (at the micro-level). Among the former, estuaries are the most vulnerable and affected ecosystems. However, despite the strong relations between climate change and estuaries, there is a gap in the literature regarding international studies across different regions investigating the impacts of climate change and variability on estuaries in different geographical zones.

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Global warming and the subsequent increase in the frequency of temperature anomalies are expected to affect marine and estuarine species' population dynamics, latitudinal distribution, and fitness, allowing non-native opportunistic species to invade and thrive in new geographical areas. Bivalves represent a significant percentage of the benthic biomass in marine ecosystems worldwide, often with commercial interest, while mediating fundamental ecological processes. To understand how these temperature anomalies contribute to the success (or not) of biological invasions, two closely related species, the native and the introduced , were exposed to a simulated heat wave.

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Atlantic horse mackerel is one of the most commercially important species in Europe. It can reach a longevity of 30 years, with potential implications in lifespan mercury contamination. This study conducted along the Portuguese coast aimed at evaluating the total Hg content and tissue distribution, to determine the annual mercury bioaccumulation patterns and the associated risk for consumption.

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Article Synopsis
  • The study analyzes the fish larvae and juvenile populations in the Mondego estuary and nearby coastal regions of Portugal, aiming to assess their role as nurseries for marine fish.
  • It identifies seasonal changes in larval density and community structure, highlighting how these variations are influenced by environmental factors, particularly temperature.
  • The findings suggest distinct nursery functions of the estuary and coastal area for early life stages of different species, emphasizing the importance of studying both larval and juvenile stages for a comprehensive understanding of fish life cycles and ecosystem connectivity.
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Contributing to the human health risk assessment, the present study aims to evaluate the ability of paralytic shellfish toxins (PSTs) to cross the human intestinal epithelium by using the Caco-2 permeability assay. A crude extract prepared from the PST producer dinoflagellate Gymnodinium catenatum strain, GCAT1_L2_16, and the PST analogue gonyautoxin-5 (GTX-5) prepared from a certified reference material (CRM) were tested. In the conditions of the assay, none of the compounds altered Caco-2 viability, or the integrity of cell monolayers.

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  • The study examines the impact of climate change on the green crab population in the Mondego estuary, highlighting that increased drought periods led to higher crab recruitment and secondary production.
  • The research reveals that juvenile crabs are found primarily upstream, while the adult population is mostly in the downstream areas, with observable color morphotypes differing by location.
  • Analyses indicate that factors like salinity and global climate patterns strongly influence crab population dynamics, emphasizing the need for long-term data to understand these changes in estuarine ecosystems.
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There is limited understanding on nearshore fish community functioning in relation to changing environmental gradients. To address this, we investigated the trait composition of fish communities in five regions along the Portuguese coast during 4 years. Northern regions were characterized by higher Chlorophyll-α and small-sized species with short lifespans.

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Indicators of oxidative stress and metabolic capacity are key factors in understanding the fitness of wild populations. In the present study, these factors were evaluated in the pelagic Southern Ocean taxa Antarctic krill (Euphausia superba) and myctophid fish (Electrona antarctica, Gymnoscopelus braueri and G. nicholsi) to establish a baseline record for future studies.

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  • The study compares toxicity testing using rat heart cells (H9c2(2-1)) with traditional fish tests, focusing on the growth inhibition caused by various effluents.
  • It finds that the cell line can serve as a viable alternative to fish lethality tests, showing comparable sensitivity patterns despite some differences in toxicity ranking.
  • The research emphasizes the importance of combining chemical and biological data to enhance environmental safety and management regarding effluent discharge.
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Biomagnification of mercury (Hg) in the Scotia Sea food web of the Southern Ocean was examined using the stable isotope ratios of nitrogen (δN) and carbon (δC) as proxies for trophic level and feeding habitat, respectively. Total Hg and stable isotopes were measured in samples of particulate organic matter (POM), zooplankton, squid, myctophid fish, notothenioid fish and seabird tissues collected in two years (austral summers 2007/08 and 2016/17). Overall, there was extensive overlap in δC values across taxonomic groups suggesting similarities in habitats, with the exception of the seabirds, which showed some differences, possibly due to the type of tissue analysed (feathers instead of muscle).

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Article Synopsis
  • Marine dinoflagellates, while important for aquatic ecosystems, can be toxic and contribute to harmful algal blooms that affect both marine life and human health.
  • The study focuses on the toxic effects of three dinoflagellate species (Gambierdiscus excentricus, Ostreopsis cf. ovata, and Prorocentrum lima) on rat mitochondrial function, specifically examining their impact on energy production and mitochondrial permeability.
  • Results indicate that G. excentricus has the most severe negative effects on mitochondrial function, leading to decreased ATP production and inducing swelling in mitochondria, which suggests a risk of cell toxicity.
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The treatment of wastewaters is crucial to maintain the ecological status of receiving waters, and thereby guarantee the protection of aquatic life and human health. Wastewater quality evaluation is conventionally based on physicochemical parameters, but increasing attention has been paid to integrate physicochemical and biological data. Nevertheless, the regulatory use of fish in biological testing methods has been subject to various ethical and cost concerns, and in vitro cell-based assays have thus become an important topic of interest.

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Local biodiversity trends over time are likely to be decoupled from global trends, as local processes may compensate or counteract global change. We analyze 161 long-term biological time series (15-91 years) collected across Europe, using a comprehensive dataset comprising ~6,200 marine, freshwater and terrestrial taxa. We test whether (i) local long-term biodiversity trends are consistent among biogeoregions, realms and taxonomic groups, and (ii) changes in biodiversity correlate with regional climate and local conditions.

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Myctophids are the most abundant fish group in the Southern Ocean pelagic ecosystem and are an important link in the Antarctic marine food web. Due to their major ecological role, evaluating the level of mercury (Hg) contamination in myctophids is important as a step towards understanding the trophic pathway of this contaminant. The concentrations of total Hg were determined in muscle, gill, heart and liver tissue of 9 myctophid species to quantify tissue partitioning variability between species.

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