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Guédron, S.; Audry, S.; Acha, D.; Bouchet, S.; Point, D.; Condom, T.; Heredia, C.; Campillo, S.; Baya, A.; Groleau, A.; Amice, Erwan; Amouroux, D.. |
Monomethylmercury (MMHg) concentrations in aquatic biota from Lake Titicaca are elevated although the mercury (Hg) contamination level of the lake is low. The contribution of sediments to the lake MMHg pool remained however unclear. In this work, seven cores representative of the contrasted sediments and aquatic ecotopes of Lake Titicaca were sliced and analyzed for Hg and redox-sensitive elements (Mn, Fe, N and S) speciation in pore-water (PW) and sediment to document early diagenetic processes responsible for MMHg production and accumulation in PW during organic matter (OM) oxidation. The highest MMHg concentrations (up to 12.2 ng L−1 and 90% of THg) were found in subsurface PWs of the carbonate-rich sediments which cover 75% of the small basin and 20%... |
Tipo: Text |
Palavras-chave: Methylmercury; Lake sediment; Early diagenesis; High altitude ecosystem; Diffusive fluxes. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00615/72735/71843.pdf |
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Goni-urriza, M. S.; Point, D.; Amouroux, D.; Guyoneaud, R.; Donard, O. F. X.; Caumette, P.; Duran, R.. |
Salinity, other physico-chemical parameters and anthropogenic pollution are the main factors affecting bacterial communities in estuaries. We estimated the impact of these parameters on the distribution of bacterial communities in the Adour estuary (France), a moderately Polluted water body characterized by short residence times of particles and water and absence of a maximum turbidity zone. Eight stations were established along the salinity gradient from freshwater to marine conditions. For the 3 typical estuarine stations (water mixing zone), samples were collected at both low and high tide and at different depths according to the position of the halocline. This sampling strategy generated 35 samples with different degrees of mixing between fresh water... |
Tipo: Text |
Palavras-chave: Bacterial communities; Salinity gradient; Heavy metals; Estuary; Halocline; T-RFLP. |
Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00249/35983/34517.pdf |
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