ENVIRONOME - INTEGRATING OMICS IN ECOTOXICOLOGY: TOOLS FOR ENVIRONMENTAL RISK ASSESSMENT

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Assessment of environmental health based on a complementary approach using metal quantification, oxidative stress and trophic ecology of two gull species (Larus michahellis & Larus audouinii) breeding in sympatry

Publication . Laranjeiro, Maria I.; Alves, Luís M.; Silva, Joana M.; Calado, Joana G.; Norte, Ana C.; Paiva, Vítor H.; Lemos, Marco F.L.; Ramos, Jaime A.; Novais, Sara C.; Ceia, Filipe R.

Metal pollution is currently a major issue in marine ecosystems, as organisms, and particularly seabirds, are exposed and accumulating increased levels from several anthropogenic sources. A set of 13 metals were quantified in two gull species breeding in sympatry, and in two distinct colonies separated by ca. 400 km. Oxidative stress was measured, and stable isotope analyses were used to link metal contamination and oxidative stress with the trophic ecology of each species/population. There was a clear segregation of metal contamination between the two species and to a much lesser extent between colonies. Overall, Audouin's gull was the most contaminated species for most metals, once this species relies mainly on fish and other marine resources. The Yellow-legged gull feeds regularly on terrestrial food sources besides fish, which may dilute contamination levels. Oxidative stress responses were related with birds' trophic ecology and foraging habitat, but apparently not with metal contamination.

2020Journal article

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Chemical predator signals induce metabolic suppression in rock goby (Gobius paganellus)

Publication . Paul, Nina; Novais, Sara C.; Lemos, Marco F. L.; Kunzmann, Andreas

In nature, a multitude of both abiotic and biotic stressors influence organisms with regard to their overall fitness. Stress responses that finally impair normal biological functions may ultimately result in consequences for whole populations. This study focused on the metabolic response of the intertidal rock pool fish Gobius paganellus towards simulated predation risk. Individuals were exposed to a mixture of skin extracts from conspecifics and chemical alarm cues from a top predator, Octopus vulgaris. Oxygen consumption rates of single fish were measured to establish standard (SMR) and routine metabolic rates (RMR) of G. paganellus, and to address the direct response towards simulated predation risk, compared to handling and light stress. The SMR of G. paganellus (0.0301 ± 0.0081 mg O2 h-1 g-1 WW) was significantly lower than the RMR (0.0409 ± 0.0078 mg O2 h-1 g-1 WW). In contrast to increased respiration due to handling and light stress, the exposure to chemical predation cues induced a significant reduction in oxygen consumption rates (0.0297 ± 0.0077 mg O2 h-1 g-1 WW). This metabolic suppression was interpreted as a result of the stereotypic freezing behaviour as antipredator response of gobiid fish. Results underline the importance of biotic interactions in environmental stress assessments and predation as a biotic factor that will provide more realistic scenarios when addressing stress impacts in tidal rock pool organisms.

2018Journal article

Open access

Homarus gammarus (Crustacea: Decapoda) larvae under an ocean acidification scenario: responses across different levels of biological organization

Publication . Rato, Lénia D.; Novais, Sara C.; Lemos, Marco F.L.; Alves, Luís M.; Leandro, Sérgio M.

The present study evaluated the effects of exposure to different target pCO2 levels: control (C: 370 μatm, pH =8.15) and ocean acidification (OA: 710 μatm, pH=7.85) on development and biochemical responses related with oxidative stress and energy metabolism during the crustacean Homarus gammarus (L.) larval development, integrating different levels of biological organization. After hatching in the laboratory, larvae from the same female brood were exposed to the described conditions from hatching until reaching Stage III (last larval stage - 11 days). H. gammarus larvae demonstrated some susceptibility when addressing the predicted pCO2 levels for 2100. Further analysis at the biochemical and physiological level highlighted the occurrence of oxidative stress in the OA scenario (Superoxide Dismutase reduction and higher DNA damage) that was followed by developmental effects, increased inter-moult period from SII to SIII and reduced growth. The extended exposure to these conditions may affect organisms' key life-cycle functions such as physiological resistance, growth, sexual maturation, or reproduction with implications in their future fitness and population dynamics.

2017Journal article

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Epigenetics in aquaculture - the last frontier

Publication . Granada, Luana; Lemos, Marco F. L.; Cabral, Henrique; Bossier, Peter; Novais, Sara C.

Aquaculture production is expanding rapidly around the world. To tackle rising production and species diversity issues, innovations in the field of aquaculture feeds, breeding, disease management and other improvements must be addressed. In this framework, the study of epigenetic mechanisms behind different aquaculture rearing processes presents great opportunities. The transcriptional impact of epigenetic modifications, triggered by environmental stimuli, has been shown to influence the organism’s phenotype. Therefore, understanding the environmental-induced epigenetic markers related to disease resistance or other economically important traits will allow the establishment of favourable breeding conditions with increased economical revenue. Several studies have shown epigenetic effects in various species, induced by different rearing conditions, with benefits for the organisms and evidences for heritability of the acquired adaptive phenotypic traits across generations, making these studies even more relevant in a production context. These studies have demonstrated the great potential of epigenetics to positively induce disease resistance, stress tolerance and attain better sex ratios in the aquatic organism. Also, in the field of nutritional epigenetics, the possibility of early nutritional programming to improve the performance of broodstock or even the long-term performance of their progeny has been suggested. In sum, an increased understanding of epigenetic mechanisms in economically important species, and the epigenetic markers leading to the most favourable phenotypic traits, will contribute to the expansion of economically viable commercial aquaculture industries. The major epigenetic mechanisms and respective analysis methods, as well as the state of the art and potential applications in aquaculture, are addressed in this review.

2018-12Journal article

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Mercury levels in commercial mid-trophic level fishes along the Portuguese coast: Relationships with trophic niche and oxidative damage

Publication . Silva, Joana M. da; Alves, Luís M.; Laranjeiro, Maria I.; Angélico, Maria M.; Norte, Ana C.; Lemos, Marco F.L.; Ramos, Jaime A.; Novais, Sara C.; Ceia, Filipa R.

Sardines (Sardina pilchardus) and mackerels (Scomber spp. and Trachurus spp.) are amongst the most common fish caught along the Iberian coast for human consumption and, as mid-trophic level organisms, they constitute essential prey in the diet of several marine predators. Thus, the assessment of trophic ecology, contamination exposure, and stress responses in such organisms provides valuable information on the environmental health in the mid-trophic chain and the potential risks for consumers. This study aims to contribute for an integrative mercury assessment of the marine ecosystem by measuring stable isotopes, mercury levels, and oxidative stress parameters in five commercial fish species in the northeast Atlantic. Samples of muscle and liver were collected from a total of 116 individuals in two fisheries assessment surveys (Spring and Autumn) along the whole Portuguese coast. Mercury concentrations and stable isotope analysis (δ13C and δ15N) were performed in the muscle, while oxidative stress parameters (lipid peroxidation and DNA damage) were measured in both muscle and liver. Mercury concentrations were found to be considerably lower than values recorded in previous studies and the limits set by the European Union law, which confirms the non-toxic status of these species along the Portuguese coast, concerning this harmful element. Interestingly, no differences were found among the three genera, despite clear differences in trophic niches. Still, mercury concentrations were significantly higher during Autumn than Spring, possibly due to upwelling events during the Summer. Moreover, no relationships between the mercury concentrations and oxidative stress parameters were found. Overall, this work provided an integrative mercury assessment of commercial fishes from the mid-trophic chain, particularly from pelagic (and neritic) regions in the northeast Atlantic, showing that mercury concentration in these species is low. However, it is important to note that this study focused on small- and medium-sized specimens (overall ranging from 13–25 cm in length), and thus higher concentrations of mercury may be present in larger fish due to bioaccumulation.

2020Journal article

Restricted access