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  • 1
    facet.materialart.
    Unknown
    VCH
    In:  Zeitschrift für Wasser- und Abwasser-Forschung, 25 . pp. 115-121.
    Publication Date: 2019-02-27
    Description: Eine Analysenmethode, die für die organische Spurenstoff-Bestimmung im Meerwasser konzipiert ist, wurde auf die Analytik von Grund- und Trinkwasser übertragen. Es zeigte sich, daß mit den üblichen Meßmethoden keine ausreichenden Analysen möglich sind. Hauptprobleme sind zu geringe Probenvolumina (1-10 1), ungenügende Clean-up Methoden und unvollständige gaschromatographische Trennungen von koeluierenden Verbindungen. Die Konzentrationen an Chlorbiphenylen im untersuchten Trinkwasser lagen zwischen 0,1 und 50 pg/1 und somit weit unter den nach der Trinkwasserverordnung vom Dezember 1990 zulässigen Höchstmengen. Die Gehalte waren aber zum Teil höher als im Meerwasser der als sehr belastet angesehenen Nordsee und Ostsee. Unter diesen Gesichtspunkten, wie auch unter Berücksichtigung der unterschiedlichen Toxizitäten der Einzelkomponenten, erscheint der in der Trinkwasserverordnung vorgeschriebene Grenzwert viel zu hoch
    Type: Article , PeerReviewed
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  • 2
    Publication Date: 2019-03-14
    Description: Arabian Sea sediments record changes in the upwelling system off Arabia, which is driven by the monsoon circulation system over the NW Indian Ocean. In accordance with climate models, and differing from other large upwelling areas of the tropical ocean, a 500,000-yr record of productivity at ODP Site 723 shows consistently stronger upwelling during interglaciations than during glaciations. Sea-surface temperatures (SSTs) reconstructed from the alkenone unsaturation index (U K′ 37) are high (up to 27°C) during interglaciations and low (22-24°C) during glaciations, indicating a glacial-interglacial temperature change of 〉3°C in spite of the dampening effect of enhanced or weakened upwelling. The increased productivity is attributed to stronger monsoon winds during interglacial times relative to glacial times, whereas the difference in SSTs must be unrelated to upwelling and to the summer monsoon intensity. The winter (NE) monsoon was more effective in cooling the Arabian Sea during glaciations then it is now.
    Type: Article , PeerReviewed
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  • 3
    facet.materialart.
    Unknown
    PANGAEA
    In:  Supplement to: Emeis, Kay-Christian; Doose, Heidi; Mix, Alan C; Schulz-Bull, Detlef (1995): Alkenone sea-surface temperatures and carbon burial at Site 846 (eastern equatorial Pacific Ocean): the last 1.3 m.y. In: Pisias, NG; Mayer, LA; Janecek, TR; Palmer-Julson, A; van Andel, TH (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 138, 605-613, https://doi.org/10.2973/odp.proc.sr.138.131.1995
    Publication Date: 2018-12-14
    Description: We analyzed the unsaturation ratio (Uk37) of long-chain ketones - a molecular sea-surface temperature (SST) indicator û concentrations of carbonate and organic carbon in sediments from Site 846 in the eastern equatorial Pacific Ocean. Based on an isotopic age model for the composite depth section of 0-46 m below seafloor and on estimates of sediment density, accumulation rates of these biogenic compounds were calculated. Our combined temperature and biogenic flux record traces conditions at the origin of the South Equatorial Current over the last 1.3 m.y. SSTs have fluctuated considerably over the interval studied. A long trend of gradual decrease from 24°C at 1.3 Ma ends between 500 and 400 Ka, when lowest values of 19°C were reached. Since this time, the temperature data indicate a warming trend to the Holocene modulated by high-amplitude variation (19° to 27°C). The inversion of the trend between 400 and 500 Ka coincides with maximal accumulation rates of carbonate, which since then have decreased. In contrast, organic carbon accumulation since then has increased in variability and in absolute values. On shorter time scales, the records show a strong link to the global climatic background. Since 1.3 Ma, carbonate (0.2-3 g/cm**2/k.y.) and organic carbon accumulation rates (2-30 mg/cm**2/k.y.) were consistently high (more than twice their modern values and those of interglacials) during glacial maxima in the benthic isotope record, when temperatures were low. However, cross-spectral analyses with the d18O record suggest that variation in organic carbon flux is not linked directly to variations in SST. Temperature maxima in our record led interglacial events by 7 k.y. in the 100-k.y. eccentricity cycle and by 5 k.y. in the 41-k.y. obliquity cycle. In contrast, maxima in organic carbon accumulation lag behind glacial maxima and low temperatures by 14 k.y. in the eccentricity cycle. On glacial/interglacial time scales, a prominent influence on SST - but not on organic carbon burial - at Site 846 appears to be the advection of cold water into the South Equatorial Current.
    Type: Dataset
    Format: text/tab-separated-values, 3062 data points
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  • 4
    Publication Date: 2018-09-27
    Type: Dataset
    Format: text/tab-separated-values, 544 data points
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  • 5
    Publication Date: 2018-09-27
    Type: Dataset
    Format: text/tab-separated-values, 594 data points
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  • 6
    Publication Date: 2017-12-11
    Description: A PYE 2-(1-pyrenyl)ethyldimethylsilylated silica gel] column HPLC in combination with MDGC-ECD has been developed for a sensitive and selective determination of toxic mono- and non-ortho PCBs in environmental samples. This technique was applied to environmental samples such as coastal water, suspended particulate material (SPM), coastal sediment, mussels, fish, bird and marine mammal. Determination of PCB 156 along with non-ortho congeners acted as matrix-integrated quality control parameter. This hyphenated technique offers one of the most sensitive way of determining non-ortho PCBs but also reveals the immense complexity of the coelution problem which unnoticed results in over estimation of toxic PCBs in the environmental samples.
    Type: Article , PeerReviewed
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  • 7
    Publication Date: 2017-08-18
    Description: Single and multidimensional GC-ECD techniques were applied to determine individual chlorobiphenyls (CBs) in solution and in suspended particles in the Baltic Sea (some data were also obtained for the adjacent German Bight in the North Sea). Large volumes (up to 1100 dm3) were analysed in transects in November 1988 and 1989 and in spring 1991. Salinity and temperature were measured continuously along the sampling tracks in all three cruises; nutrients and pH only in the latter two cruises. Concentrations of individual CBs in solution were in the sub- and low pg dm−3 range (detection limit being 0.05 pg dm−3), and of their sum between 2 and 237 pg dm−3. These concentrations are considerably lower than previously reported data. This is mainly the result of the elimination of contamination and interference problems in the sampling, clean-up and GC-ECD procedures. It may also partly reflect the reduction in the production and use of PCBs in the last decade. The highest concentrations in solution originated from local sources in the Belt Sea and the Gulf of Finland. Regional differences were found for the compositions of the CB mixtures in solution. The lowest concentrations of CBs in solution were found in areas and periods of plankton production (spring 1991), with ΣCB concentrations between 2 and 14 pg dm−3. The compositions of the CB mixtures showed regional differences in each cruise. These could be interpreted in terms of mixing between different water bodies. The classification of transects on the basis of these CB patterns agreed well with the distinction of water bodies on the basis of T-S diagrams and hydrochemical data. Concentrations of individual CBs in suspension were generally 0.1–0.5 pg dm−3, those of their sum (ΣCB) between 4 and 6 pg dm−3 during the autumn cruises. Extremely high values were found in the Belt Sea-Kattegat area in spring 1991 (up to 589 pg dm−3 for individual CBs and up to 2859 pg dm−3 for ΣCB). This probably reflects the uptake of CBs into particulates during a plankton bloom. Primary production may effectively remove CBs from the water column into the sediments. The amounts of chlorobiphenyls presently stored in the sediments of the Baltic Sea exceed the amounts in the water column by several orders of magnitude. The compositions of the CB mixtures differed considerably between solution and suspension. The relations between log K′d (apparent particle/water partition coefficient) and log Kow (octanol-water distribution coefficient) suggest the existence of (quasi-)equilibrium conditions in autumn. Deviations from this behaviour arise from biological activity in spring. The contribution of toxic congeners to the CB mixtures was dominated by the mono- and di-ortho-Cl substituted derivatives of the most toxic non-ortho-Cl CBs. The toxicity of the CB mixtures in solution was between 0.01 and 12fg dm−3 TEQs (TCDD toxic equivalents). CBs-77, -118, -105 and -156 had the largest contributions to TEQs.
    Type: Article , PeerReviewed
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  • 8
    Publication Date: 2017-06-27
    Description: A seasonally-varying sedimentation pattern was observed for the alkenone flux measured with sediment traps in the northern North Atlantic. In the Norwegian Sea (traps were set at 500, 1000 and 3000 m) the alkenone flux varied between 0.1 and 7.1 μg m−2 d−1 and followed the seasonal pattern of the bulk parameters. Maximum fluxes occurred from mid-October until mid-November and were also high in May. A surprising result was that considerably higher particle fluxes were observed at 3000 m. For the alkenone flux, the highest additional input of 250% was observed during the period when sediment resuspension was greatest in summer. At the Barents Sea continental margin (traps at 1840 and 1950 m) the alkenone fluxes follow the sedimentation pattern of the bulk parameters, with a less visible signal of distinct seasonality observed in the 1950 m trap. The sedimentation of total alkenones varied between 0.8 and 144 μg m−2 d−1 at 1840 m and between 0.5 and 31.0 μg m−2 d−1 at 1950 m. Resuspension and lateral advection contributed significantly to measured fluxes in the two near-bottom traps. Alkenone concentrations were determined in faecal pellets of Appendicularia, ostracods and euphausids from selected samples at the Barents Sea site. The alkenone flux in pellets (4% to 24% of total) was 5 to 6 times higher at 1950 m depth than at 1840 m and the major part (77–78%) of the total flux of C37:3 reaching the near-bottom trap at 1950 m was associated with faecal pellets of the meso-zooplankton. Spatial and temporal variations of the U37k′ signals were observed, indicating that the imprint in the alkenone signal depends on the origin and transport pathway of the organic material. Strong deviations occur in areas where nepheloid layers contribute particles of long residence times to the primary flux.
    Type: Article , PeerReviewed
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  • 9
    Publication Date: 2017-08-18
    Description: A system for in-situ filtration and extraction of organics in natural waters has been developed and tested down to 4000 m in the Atlantic Ocean. Up to 2000 dm3 water can be filtered and extracted at low suspended matter concentrations. The sampling equipment has new features for the analysis of trace organic compounds: contamination is extremely low, this can be checked and cured, if necessary, and water flow can be selected and maintained at a constant rate. Various resins can be applied, with different optimum flow rates for the efficient extraction of the compounds of interest. The properties of the resin (here XAD-2) do not change with depth. The operation of the unit is controlled by menu-driven software. All relevant data are stored for later evaluation. Tests in the deep Atlantic resulted in total procedural blanks, including sampling, as low as 0/003 pg dm−3 for individual chlorobiphenyls (CBs), HCB and DDE and 0.5 pg dm−3 for individual PAHs. Actual dissolved concentrations were in the range 0.005–0.1 pg dm−3 for CBs, HCB and DDE and 0.5–140 pg dm−3 for PAHs.
    Type: Article , PeerReviewed
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  • 10
    facet.materialart.
    Unknown
    Leitstelle Dt. Forschungsschiffe
    In:  Forschungsschiff Maria S. Merian : Reise Nr. MSM ... = Research vessel Maria S. Merian, 01 . Leitstelle Dt. Forschungsschiffe, Hamburg, Germany, 45 pp.
    Publication Date: 2013-04-10
    Type: Report , NonPeerReviewed
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