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13 páginas, 6 figuras, 1 tabla ; Modern diatom distribution patterns in the surface sediment of the Ferrol Ría and their relationship to the hydrography and diatom patterns in the water column were studied to determine the hydrographic influence on the record of these biogenic components. Diatom abundance in the water column was assessed for different oceanographic periods and compared with the biosiliceous sedimentary record. Very low abundances were found in the water column during the winter, whereas in spring and summer, diatoms proliferated. Chaetoceros spp. formed the bulk of the water column community during spring and summer, followed by Thalassionema nitzschioides and Rhizosolenia spp. Nitzschia longissima represented a significant portion of the winter assemblage, together with Paralia sulcata and benthic taxa. Leptocylindrus danicus, N. longissima and Skeletonema costatum characterized the autumn campaign, when stratification of the waters occurs, with L. danicus being especially abundant in the outer ría. Seasonal hydrographic and associated productivity patterns govern the abundance and assemblage of the diatoms preserved in surface sediments. Samples located in the inner ría area and its margins exhibited the highest abundances of diatoms, and were primarily dominated by benthic species. The freshwater group, crysophycean cysts and phytoliths were present in the landward stations influenced by river runoff. The middlería was characterized by P. sulcata and Thalassiosira spp., with minor occurrences of the benthic and freshwater group. Chaetoceros R.S., L. danicus R.S. and T. nitzschioides typified the outer ría, an assemblage that corresponds to nutrient-rich coastal areas of high productivity influenced by oceanic waters, demonstrating the impact of oceanic waters flowing into the embayment due to enhanced tidal mixing through the narrow channel. Therefore, sediment diatom assemblages reflect diatom production patterns in the water column of the Ría. However, we must proceed with caution when interpreting the paleorecord in the inner area due to the high contribution of allochthonous taxa, which is indicative of low water depths. This paper contributes to a better understanding of diatom thanatocoenosis in the Galician Rías, where very few studies of this kind have been done to date ; This work was supported by FEDER-CICYT under the project 'Biogeochemical Processes in the Ferrol Ría: Fertilization by Nutrients and Spatio- temporal Variation of Metals in the Sediment', ref. 1FD97-0479-C03-02. Patricia Bernárdez thanks the Spanish Government (FPU program) and Xunta de Galicia for financial support. ; Peer reviewed

31 pages, 5 figures. ; Evaluation of biogeochemical processes in Anthropocene deep-sea sediments require accurate dating techniques. Here we show the results of an approach using high resolution low level background gamma spectrometry with two simultaneous hyper-pure germanium (HPGe) detectors. The quantitative role of the deepest zones (>3000 m depth) of the Irminger Basin (Subpolar North Atlantic Ocean) as a carbon sink during the Anthropocene is evaluated combining a chronology based in the natural radionuclide 210Pb with sedimentological analysis and elemental composition. The average sedimentation rate of the central Irminger is 1.28 ± 0.18 mm·yr−1, with a mean weighted flux to the sediment for inorganic and organic carbon of 46 ± 15 g·Cinorg·m−2·yr−1 and 8 ± 1 g·Corg·m−2·yr−1. The biogenic fraction of the mass flux is increased since the XXth century. The contribution of the deepest zones of the Irminger Basin to the Anthropocene carbon sequestration in the North Atlantic Ocean is considerable at basin-scale. ; For this work M. Fontela was funded by the Spanish Ministry of Economy and Competitiveness through the BOCATS project supported by the Spanish Government. ; Peer reviewed