Добірка наукової літератури з теми "Goélands – Effets de la pollution – Arctique"
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Дисертації з теми "Goélands – Effets de la pollution – Arctique"
Jouanneau, William. "Maternal transfer and physiological consequences of per- and polyfluoroalkyl substances in seabird eggs." Electronic Thesis or Diss., La Rochelle, 2022. http://www.theses.fr/2022LAROS043.
Повний текст джерелаThe developmental period is a very sensitive phase since it sees the synthesis and maturation of all organs and functions of the future organism. Therefore, any disruption experienced early in life may have substantial subsequent consequences. In the context of the considerable impact of Human activities on wildlife, seabirds are particularly at risk since they are exposed to numerous threats, including fisheries interactions, habitat destruction, or environmental pollution. Among them, the later is maybe the most insidious, since it can also be transferred to the progeny via maternal transfer in eggs, and cause adverse effects as early as during the development. The 20th century saw the emergence of numerous synthetic substances. Among them, the per- and polyfluoroalkyl substances (PFAS) are found in seabird eggs, but little is known about their effects. In this thesis, I aimed at investigating the maternal transfer of PFAS in an Arctic seabird, the black-legged kittiwake (Rissa tridactyla). I also examined the eventual consequences of legacy and emerging PFAS exposure for the embryo in this species and in the yellow-legged gull (Larus michahellis). I found relatively high concentrations of legacy PFAS in eggs as well as some emerging compounds including 7:3 FTCA or PFEcHS. PFAS physicochemical characteristics influenced their transfer efficiency. My results also suggested that females PFAS might affect their transfer of maternal hormones in eggs, which may ultimately affect offspring at short and long term. Finally, I found no indications that PFAS deposited in eggs may affect the developing embryo on biomarkers of ageing (telomere length) or metabolism. I therefore suggested that both studied populations should be relatively safe at least at the PFAS concentrations measured in their eggs. Nonetheless, additional studies would be needed to assess how PFAS may affect the endocrine maternal transfer and its consequences for the embryo
Larose, Catherine. "Interactions entre composition chimique et populations microbiennes de la neige : quelles sont les conséquences sur le cycle du mercure en Arctique ?" Université Joseph Fourier (Grenoble), 2010. http://www.theses.fr/2010GRENU004.
Повний текст джерелаThe main objective of this thesis is to characterize the interactions between seasonal snow chemistry and microbial community structure in an arctic snowpack. In order to do so, the biotic and abiotic compartments of the snowpack must be first characterized. From snow and meltwater samples obtained during a two-month field study held in Ny-Ålesund (Svalbard, Norway, 78°56'N, 11°52'E) in 2007, we showed that the sequence diversity in arctic snow and meltwater libraries is elevated. We also examined the fate of Hg in an arctic snowpack, from its deposition during atmospheric mercury depletion events up until its transfer during snow melt and reported an increase in methylmercury concentrations in the snowpack during late spring. The results from this campaign highlighted the need to improve our knowledge on mercury speciation and led to the development of a mer-lux biosensor to measure the bioavailable fraction of mercury. We deployed the biosensor during a second two-month field campaign in Ny-Ålesund in spring 2008 and the results obtained led to a novel model for mercury methylation in oxic environments. In parallel, we followed changes in microbial community structure in snow and meltwater samples using a 16S microarray. We modeled the interactions between snow chemistry and community structure and found a significant co-structure. We also explored functional community changes due to mercury contamination of snowpacks. Based on our results, methylmercury affects community structure and function at concentrations much lower than previously reported. Our results provide a basis for further studies on the interaction between chemistry and microbial community structure
Auby, Antoine. "Modélisation à haute résolution du transport de polluants à longue distance." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00735198.
Повний текст джерелаMasbou, Jérémy. "Étude des processus métaboliques, écologiques et biogéochimiques contrôlant le fractionnement isotopique du Hg chez les mammifères marins de l'Arctique." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/3093/.
Повний текст джерелаSince the discovery of atmospheric Hg depletion events (AMDE) in the Arctic, the Polar Regions have become key in understanding the Hg global cycle. The impact of Hg on human health depends on both Hg concentration and chemical form. In particular, monomethylmercury (MMHg) is a potent neurotoxin. High MMHg concentrations are observed in Arctic top predators due to bioaccumulation and biomagnification processes in the food webs. Hence, the characterization of the transformations leading to the formation (methylation) and the degradation (demethylation) of MMHg is of great concern to assess its fate and impact in aquatic ecosystems. In this context, we present an environmental study on three Arctic bio-indicators: the ringed seal (Pusa hispida), the beluga whale (Delphinaperus leucas) and the polar bear (Ursus maritimus). Hg isotope analysis of the bio-indicator liver tissues show both mass dependent isotope fractionation (MDF, delta202Hg) and mass independent fractionation (MIF, delta199Hg). While the changes in d202Hg are widely linked to in vivo metabolic processes, the time trend (1988-2002, Pusa hispida) and the latitudinal gradient (60°N-71°N, Delphinaperus leucas) observed for ?199Hg signatures suggests the influence of sea ice cover on the Arctic biogeochemical Hg cycle. In a second part of this dissertation, we propose a novel and promising molecular approach with the first measurements of the isotopic compositions of Hg and carbon on the MMHg molecule in biological samples. These results are very promising for tracing MMHg origin in aquatic environments
Guyot, Gwennolé. "Caractérisation des propriétés microphysiques des nuages et de l'interaction aérosol-nuage en Arctique à partir de mesures in-situ au sol pendant la campagne CLIMSLIP-NyA, Svalbard." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22699/document.
Повний текст джерелаThe arctic region is especially sensitive to climate change. At high latitudes, arctic clouds have an important effect on the surface radiative budget. The first part of this work consists in a ground based cloud instrumentation intercomparison in the PUY station in May 2013. The measurements showed a good correlation between the effective diameters and the droplet size distributions obtained by the instruments, but with a systematical bias on the concentrations. These biases have been relied to the assessment of the sampling volume and we thus proposed a methodology to standardize the data according to an ensemble of particles probe. Moreover, the FSSP and the FM have been the subject of experiments to assess the influence of the deflection angle according to exterior wind and the wind speed. The second part of this work is about the measurement campaign at the Mount-Zeppelin station, Ny-Alesund, Svalbard, from March to May 2012 in the frame of the CLIMSLIP project. A comparison has been performed between a « polluted » case, with air masses coming from East Asia and Europe, and a « clean » case, where the aerosol sources are predominantly local and do not exceed the northern Europe. The results showed that the polluted case possessed higher concentrations in BC, aerosols and drops, an accumulation mode more important, weaker droplet diameters and higher activation fraction. Finally, the first and second aerosol indirect effects have been quantified
Книги з теми "Goélands – Effets de la pollution – Arctique"
Ryckman, D. P. Les contaminants dans les oeufs des Goélands argentés des Grands Lacs: 25 années de surveillance des niveaux et des effets. Ottawa, Ont: Environnement Canada, 1997.
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