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  • 1
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This investigation represents the first integrated study of primary production, nutrient dynamics and mineralisation in a northeastern fjord of Greenland. The data presented represent conditions and activities during the early summer thaw (first 2 weeks of July). Primary production (5.3 mmol C m−2 d−2) and chlorophylla (4.1 μg 1−1) values were found to be comparable with measurements from other Arctic regions. Water column N-fixation rates were low (〈0.02 μmol N m−1 d−1), but comparable with other estuarine systems. Despite a constant low temperature in the bottom waters (-1.0 to -1.8°C), a high sedimentary O2 uptake (740 μmol m−2 h−2) was observed and was primarily caused by the presence of benthic infauna. Bioturbation by benthic infauna was reflected in both homogeneous210Pb and137Cs profiles in the upper 4 cm of the sediment. Permanent accumulation within Young Sound was measured to 0.12 cm/year corresponding to 153 mmol C m−2 year−1 and 15 mmol N m−2 year−1. Rates of nitrification (22 μmol m−2 h−1) and denitrification (9 μmol m−2 h−1) were comparable with rates reported for other sediments with much higher environmental temperatures. Suphate reduction rates integrated over the upper 12 cm of the sediment were calculated to be 44 μmol m−2h−1.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  This investigation represents the first integrated study of primary production, nutrient dynamics and mineralisation in a northeastern fjord of Greenland. The data presented represent conditions and activities during the early summer thaw (first 2 weeks of July). Primary production (5.3 mmol C m-2 d-1) and chlorophyll a (4.1μg l-1) values were found to be comparable with measurements from other Arctic regions. Water column N-fixation rates were low (〈0.02 μmol N m-1 d-1), but comparable with other estuarine systems. Despite a constant low temperature in the bottom waters (−1.0 to −1.8°C), a high sedimentary O2 uptake (740 μmol m-2 h-1) was observed and was primarily caused by the presence of benthic infauna. Bioturbation by benthic infauna was reflected in both homogeneous 210Pb and 137Cs profiles in the upper 4 cm of the sediment. Permanent accumulation within Young Sound was measured to 0.12 cm/year corresponding to 153 mmol C m-2 year-1 and 15 mmol N m-2 year-1. Rates of nitrification (22 μmol m-2 h-1) and denitrification (9 μmol m-2 h-1) were comparable with rates reported for other sediments with much higher environmental temperatures. Suphate reduction rates integrated over the upper 12 cm of the sediment were calculated to be 44 μmol m-2 h-1.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1616-7228
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Description / Table of Contents: Zusammenfassung Vier verschiedene Sedimentgreifer wurden mehrmals an einer Position in der westlichen Ostsee eingesetzt, auf der sich weiches, schlickiges Sediment befindet. Die künstlichen Radioisotope137Cs und134Cs, die hier ein charakteristisches vertikales Profil aufweisen, wurden in vertikalen Schichten aus den verschiedenen Kernen durch die teilnehmenden Laboratorien bestimmt. Um analytische Unterschiede zwischen den Laboratorien zu vermeiden, die lediglich auf Kalibrationsfehler zurückzuführen sind, wurde eine Probe mit etwa 8,5 kg Trockenmasse von der Oberfläche entnommen. Diese Probe wurde homogenisiert und von weiteren Laboratorien außerhalb dieses Experiments analysiert. Diese Probe wird als “Standardprobe” betrachtet. Alle Ergebnisse der verschiedenen Sedimentkerne werden auf diese Probe bezogen. Künstliche und natürliche Radionuklide wie40K,134Cs,137Cs,106Ru,125Sb,239, 240Pu,238Pu,241Am,210Pb,210Po,226Ra,238U und232Th wurden in dieser Probe bestimmt. Die Methoden und Ergebnisse der Analysen werden diskutiert. Zur Vervollständigung des Vergleichs der Sedimentkerne werden die Metalle Mn, Zn, Cu und Pb in vertikalen Schichten bestimmt.
    Abstract: Résumé Quatre types de carrotiers ont été répétitivement utilisés pour collecter des sédiments tendres et vaseux dans l'ouest de la Mer Baltique. Les radioisotopes artificiels137Cs et134Cs, dont les profils sont charactéristiques dans les carottes, ont été mesurés dans plusieurs tranches verticales par les laboratoires participants. Afin d'éviter les différences analytiques résultant d'erreurs de calibration, un échantillon de référence de 8.5 kg a été prélevé dans le sédiment superficiel. Aprés homogénéisation, des sous-échantillons ont été analysés par des laboratoires étrangers à l'opération d'intercalibration. Des radionuclides artificiels et naturels tels que40K,134Cs,137Cs,106Ru,125Sb,239, 240Pu,238Pu,241Am,210Pb,210Po,226Ra,238U et232Th ont été déterminés dans cet échantillon. Ce matériel constitue un “standard”, untilisé comme référence pour les analyses des sédiments prélevés avec les différents carottiers. Les méthodes et les résultats des analyses sont discutés. La détermination des métaux Mn, Zn, Cu et Pb, compléte la comparaison entre les différents types de préleveurs.
    Notes: Summary Four different sediment samplers were applied several times in the western Baltic Sea at a position with soft, muddy sediment. The artificial radioisotopes137Cs and134Cs, exhibiting a characteristic vertical profile in the cores, were determined from vertical slices of the different cores by the laboratories participating. In order to avoid analytical differences between the laboratories merely due to calibration errors, one bulk sample of about 8.5 kg dry weight was collected from the surface, homogenized and analysed by laboratories outside this experiment. This sample is regarded as the “standard” sample, which all results from the sediment corers are referred to. Artificial and natural radionuclides such as40K,134Cs,137Cs,106Ru,125Sb,239, 240Pu,238Pu,241Am,210Pb,210Po,226Ra,238U, and232Th were determined in this sample. The methods and results of the analyses are discussed. The comparison of the sediment corers are complemented by the determination of the metals Mn, Zn, Cu, and Pb in vertical slices.
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2019-09-23
    Description: Based on a sediment vibro corer, a tool for the sampling of sub-seafloor groundwater aquifers has been developed and successfully deployed in a coastal area of the western Baltic. The device was designed to obtain pure groundwater samples from coarse sediments to be used for tracer investigations and CFC age dating. Operated from a medium size research vessel, a well pipe tipped with a filter segment is vibrated into the sediment down to the aquifer. Groundwater entering the filter is pumped to the ship by a conventional submersible pump situated in the well's filter tip. Groundwater is continuously analysed on board for O2, salinity, pH, Eh and temperature, prior to sampling for CFC and radioisotope analysis. All parameters indicate that pure groundwater had been obtained. CFC concentrations are very low suggesting that the groundwater of this shallow sub-seafloor aquifer recharged prior to 1950. This finding is in accordance with other hydrogeological evidence that this aquifer, located only 4–5 m below the seafloor, is connected to fairly deep confined sandy aquifers on land of Pleistocene or Miocene age. Applying the method described, it is possible to obtain sufficient sample volumes for analyses of natural groundwater tracers such as radon-222 and CFCs which can be used to trace submarine groundwater discharge as well as the origin of groundwater in such environments.
    Type: Article , PeerReviewed
    Format: text
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