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Eckbo, N., Le Bohec, C., Planas-Bielsa, V., Warner, N. A., Schull, Q., Herzke, D., et al. (2019). Individual variability in contaminants and physiological status in a resident Arctic seabird species. Environ. Pollut., 249, 191–199.
Résumé: While migratory seabirds dominate ecotoxicological studies within the Arctic, there is limited knowledge about exposure and potential effects from circulating legacy and emerging contaminants in species who reside in the high-Arctic all year round. Here, we focus on the case of the Mandt's Black guillemot (Cepphus grylle mandril) breeding at Kongsfjorden, Svalbard (79.00 degrees N, 11.66 degrees E) and investigate exposure to legacy and emerging contaminants in relation to individual physiological status, i.e. body condition, oxidative stress and relative telomere length. Despite its benthic-inshore foraging strategy, the Black guillemot displayed overall similar contaminant concentrations in blood during incubation (Sigma PCB11(15.7 ng/g w.w.) > Sigma PFAS(5) (9.9 ng/g w.w.)> Sigma Pesticides(9) (6.7 ng/g w.w.) > Sigma PBDE4 (2.7 ng/g w.w.), and Hg (0.3 mu g/g d.w.) compared to an Arctic migratory seabird in which several contaminant-related stress responses have been observed. Black guillemots in poorer condition tended to display higher levels of contaminants, higher levels of reactive oxygen metabolites, lower plasmatic antioxidant capacity, and shorter telomere lengths; however the low sample size restrict any strong conclusions. Nevertheless, our data suggests that nonlinear relationships with a threshold may exist between accumulated contaminant concentrations and physiological status of the birds. These findings were used to build a hypothesis to be applied in future modelling for describing how chronic exposure to contaminants may be linked to telomere dynamics. (C) 2019 Published by Elsevier Ltd.
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Espinosa, F., & Rivera-Ingraham, G. A. (2016). Subcellular evidences of redox imbalance in well-established populations of an endangered limpet. Reasons for alarm? Mar. Pollut. Bull., 109(1), 72–80.
Résumé: Intertidal species are more vulnerable to anthropogenic disturbances than others inhabiting subtidal and offshore habitats. Coastal development frequently results in trace-metal pollution. For endangered species such as Patella ferruginea it can be a high risk that leads local populations to extinction. Three localities were surveyed, one within a natural and unpolluted area and the other two within the harbor of Ceuta (Strait of Gibraltar), on breakwaters outside and inside. The specimens collected inside the harbor reached 3-fold higher Hg content than for those incoming from the natural area. PERMANOVA test indicated that metal composition of the specimens from inside the harbor was different from the rest. In addition, evidence of cell damage was detected in the specimens from the harbor area. This highlights the urgency of undertaking a physiological evaluation of some of the most vulnerable populations, establishing eco-physiological protocols for monitoring and managing populations settled on artificial substrata. (C) 2016 Elsevier Ltd. All rights reserved.
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Fleury, E., Moal, J., Boulo, V., Daniel, J. Y., Mazurais, D., Henaut, A., et al. (2010). Microarray-Based Identification of Gonad Transcripts Differentially Expressed Between Lines of Pacific Oyster Selected to Be Resistant or Susceptible to Summer Mortality. Mar. Biotechnol., 12(3), 326–339.
Résumé: Summer mortality of the Pacific oyster Crassostrea gigas is the result of a complex interaction between oysters, their environment, and pathogens. Heredity appears to be a major factor determining the sensitivity of oysters to summer mortality, allowing resistant (R) and susceptible (S) lines to be produced. We conducted genome-wide expression profiling of R and S gonads during the 3-month period preceding a summer mortality event, using a cDNA microarray that we designed. ANOVA analysis revealed that 34 genes were differentially expressed between R and S lines on four dates preceding the mortality event. Annotation of some of these genes highlights reproduction and its allocation and antioxidant defenses as the main pathways that operate differentially between R and S lines. This transcriptional analysis provides new indications to define markers for quantitative trait loci searches and functional studies and evaluate the potential role of each gene in the resistance to summer mortality.
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Jean, N., Dumont, E., Herzi, F., Balliau, T., Laabir, M., Masseret, E., et al. (2017). Modifications of the soluble proteome of a mediterranean strain of the invasive neurotoxic dinoflagellate Alexandrium catenella under metal stress conditions. Aquat. Toxicol., 188, 80–91.
Résumé: The soluble proteome of the mediterranean strain ACT03 of the invasive neurotoxic dinoflagellate Alexandrium catenella exposed to lead or zinc at 6, 12 or 18 mu M (total concentrations), or under control conditions, was characterized by two-dimensional gel electrophoresis (2-DE). Zinc reduced (P < 0.05) the total number of protein spots (-41%, -52% and -60%, at 6, 12 or 18 M, respectively). Besides, most of the proteins constituting the soluble proteome were down-regulated in response to lead or zinc stresses. These proteins were involved mainly in photosynthesis (20-37% for lead; 36-50% for zinc) (ribulose-1,5-bisphosphate carboxylase/oxygenase: RUBISCO; ferredoxin-NADP(+) reductase: FNR; peridinin-chlorophyll a-protein: PCP), and in the oxidative stress response (29-34% for lead; 17-36% for zinc) (superoxide dismutase: SOD; proteasome alpha/beta subunits). These negative effects could be partly compensated by the up-regulation of specific proteins such as ATP-synthase beta subunit (+16.3 fold after exposure to lead at 12 M). Indeed, an increase in the abundance of ATP-synthase could enrich the ATP pool and provide more energy available for the cells to survive under metal stress, and make the ATP-synthase transport of metal cations out of the cells more efficient. Finally, this study shows that exposure to lead or zinc have a harmful effect on the soluble proteome of A. catenella ACT03, but also suggests the existence of an adaptative proteomic response to metal stresses, which could contribute to maintaining the development of this dinoflagellate in trace metal-contaminated ecosystems.
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Queiros, Q., Fromentin, J. - M., Gasset, E., Dutto, G., Huiban, C., Metral, L., et al. (2019). Food in the sea: size also matters for pelagic fish. Front. Mar. Sci., 6, Unsp-385.
Résumé: Small pelagic fish are key components of marine ecosystems and fisheries worldwide. Despite the absence of recruitment failure and overfishing, pelagic fisheries have been in crisis for a decade in the Western Mediterranean Sea because of a marked decline in sardine size and condition. This situation most probably results from bottom-up control and changes in the plankton community toward smaller plankton. To understand such an unusual phenomenon, we developed an original and innovative experimental approach investigating the mechanisms induced by a reduction in the quantity and size of sardine prey. While experimentations offer the unique opportunity to integrate behavior and ecophysiology in understanding key demographic processes, they remain rarely used in fisheries science, even more so on small pelagics due to the notorious difficulty to handle them. The results revealed that food size (without any modification of its energy content) is as important as food quantity for body condition, growth and reserve lipids: sardines that fed on small particles had to consume twice as much as those feeding on large particles to achieve the same condition and growth. Such a strong impact of food size (based on 100 vs. 1200 mu m pellets) was unexpected and may reflect a different energy cost or gain of two feeding behaviors, filter-feeding vs. particulate-feeding, which would have to be tested in further study. As increasing temperature favors planktonic chains of smaller size, climate change might actually accelerate and amplify such phenomenon and thus strongly affect fisheries.
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