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  • 1
    Electronic Resource
    Electronic Resource
    Interaction between interstitial water and sediment in two cores of Lac Léman, Switzerland (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 363-375 
    Details
    ISSN: 1573-5117
    Keywords: pore water ; lake sediments ; Fe species ; Mössbauer ; Mn species ; heavy metals ; authigenic mineral phases ; Lac Léman
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pore fluids of the sediments collected at the deepest point of Lac Léman (Switzerland) are supersaturated with respect to vivianite and siderite. In the presence of sulphide, the iron solubility is controlled entirely by the amorphous iron sulphides. As the iron (II) becomes dominant, the formation of siderite occurs and evidence of this, in the solid phase, can be obtained by the use of Mössbauer spectroscopy and some sequential chemical extractions. The amount of ‘siderite iron’ decreases from about 10% near the sediment surface to a few percent in the lower levels of the sediment (〈10 cm). Evidence for vivianite formation could not be obtained even in the lower layers, despite the precautions taken to avoid oxidation. Although the trace metal behaviour in the solid phase is well correlated with the iron and manganese, availability in the pore fluid is dependent on the adsorption on, or co-precipitation with, finely dispersed colloids, which pass through a 0.45 µg filter. Trace metal concentrations in pore fluid were not directly related to total elemental concentrations in the solid phase, and did not reflect cumulative trends associated with anthropogenic enrichment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02391952
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The manganese cycle in Lac Léman, Switzerland: the role ofMetallogenium (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 323-340 
    Details
    ISSN: 1573-5117
    Keywords: manganese cycle ; Metallogenium ; Lac Léman
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The manganese pathways in Lac Léman have been investigated on the basis of chemical analyses undertaken on water, suspended solids, bottom sediments and interstitial water samples. The various modes of occurrence of Mn have been determined by means of visual examination using SEM and TEM (scanning and transmission electron microscopy), by microanalysis (EDAX) of various sediment fractions, by chemical analysis of the dissolved phase, and by chemical speciation and XRD of bottom sediments. Fluxes to and from the sediment have also been computed. The time-depth variations of Mn in the water column are characterized by (a) a very steep gradient of Mn sol. from the sediment interstitial water (15 mg l−1) to the overlying water, 2 m above the bottom(500 µg l−1), (b) an accumulation of Mn part. between 280 m and the interface at 310 m, consisting of mineralized colonies ofMetallogenium. The abundance ofMetallogenium colonies is inversely related to O2 concentration; the optimal value for the bacterium Mn fixation is around 1 mg l−1. Because of the quasi-anoxic state of the bottom sediments and overlying water, Mn diffuses from a ‘source layer’, 2–5 cm below the interface (a) upwards across the interface, before being taken up byMetallogenium, and (b) downwards to a ‘sink layer’, in which large amounts of Mn-carbonate precipitate. Particulate Mn sedimentation rates measured in traps show that downwards Mn flux due toMetallogenium settling approximately balances the upwards soluble flux due to diffusion. Quantitatively, the process of Mn cycling in Lac Léman is, therefore, limited to the lowermost part of the hypolimnion. Although Zn and Cd seem to follow the same cycle as Mn, Fe behaves in a different manner; it was not taken up byMetallogenium at the time of our study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02391949
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Interaction between interstitial water and sediment in two cores of Lac Léman, Switzerland (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 363-375 
    Details
    ISSN: 1573-5117
    Keywords: pore water ; lake sediments ; Fe species ; Mössbauer ; Mn species ; heavy metals ; authigenic mineral phases ; Lac Léman
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pore fluids of the sediments collected at the deepest point of Lac Léman (Switzerland) are supersaturated with respect to vivianite and siderite. In the presence of sulphide, the iron solubility is controlled entirely by the amorphous iron sulphides. As the iron (II) becomes dominant, the formation of siderite occurs and evidence of this, in the solid phase, can be obtained by the use of Mössbauer spectroscopy and some sequential chemical extractions. The amount of ‘siderite iron’ decreases from about 10% near the sediment surface to a few percent in the lower levels of the sediment (〈10 cm). Evidence for vivianite formation could not be obtained even in the lower layers, despite the precautions taken to avoid oxidation. Although the trace metal behaviour in the solid phase is well correlated with the iron and manganese, availability in the pore fluid is dependent on the adsorption on, or co-precipitation with, finely dispersed colloids, which pass through a 0.45 µg filter. Trace metal concentrations in pore fluid were not directly related to total elemental concentrations in the solid phase, and did not reflect cumulative trends associated with anthropogenic enrichment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000036
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The manganese cycle in Lac Léman, Switzerland: the role ofMetallogenium (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 323-340 
    Details
    ISSN: 1573-5117
    Keywords: manganese cycle ; Metallogenium ; Lac Léman
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The manganese pathways in Lac Léman have been investigated on the basis of chemical analyses undertaken on water, suspended solids, bottom sediments and interstitial water samples. The various modes of occurrence of Mn have been determined by means of visual examination using SEM and TEM (scanning and transmission electron microscopy), by microanalysis (EDAX) of various sediment fractions, by chemical analysis of the dissolved phase, and by chemical speciation and XRD of bottom sediments. Fluxes to and from the sediment have also been computed. The time-depth variations of Mn in the water column are characterized by (a) a very steep gradient of Mn sol. from the sediment interstitial water (15 mg l−1) to the overlying water, 2 m above the bottom(500 µg l−1), (b) an accumulation of Mn part. between 280 m and the interface at 310 m, consisting of mineralized colonies ofMetallogenium. The abundance ofMetallogenium colonies is inversely related to O2 concentration; the optimal value for the bacterium Mn fixation is around 1 mg l−1. Because of the quasi-anoxic state of the bottom sediments and overlying water, Mn diffuses from a ‘source layer’, 2–5 cm below the interface (a) upwards across the interface, before being taken up byMetallogenium, and (b) downwards to a ‘sink layer’, in which large amounts of Mn-carbonate precipitate. Particulate Mn sedimentation rates measured in traps show that downwards Mn flux due toMetallogenium settling approximately balances the upwards soluble flux due to diffusion. Quantitatively, the process of Mn cycling in Lac Léman is, therefore, limited to the lowermost part of the hypolimnion. Although Zn and Cd seem to follow the same cycle as Mn, Fe behaves in a different manner; it was not taken up byMetallogenium at the time of our study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00940123
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Interaction between interstitial water and sediment in two cores of Lac Léman, Switzerland (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 363-375 
    Details
    ISSN: 1573-5117
    Keywords: pore water ; lake sediments ; Fe species ; Mössbauer ; Mn species ; heavy metals ; authigenic mineral phases ; Lac Léman
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pore fluids of the sediments collected at the deepest point of Lac Léman (Switzerland) are supersaturated with respect to vivianite and siderite. In the presence of sulphide, the iron solubility is controlled entirely by the amorphous iron sulphides. As the iron (II) becomes dominant, the formation of siderite occurs and evidence of this, in the solid phase, can be obtained by the use of Mössbauer spectroscopy and some sequential chemical extractions. The amount of ‘siderite iron’ decreases from about 10% near the sediment surface to a few percent in the lower levels of the sediment (〈10 cm). Evidence for vivianite formation could not be obtained even in the lower layers, despite the precautions taken to avoid oxidation. Although the trace metal behaviour in the solid phase is well correlated with the iron and manganese, availability in the pore fluid is dependent on the adsorption on, or co-precipitation with, finely dispersed colloids, which pass through a 0.45 µg filter. Trace metal concentrations in pore fluid were not directly related to total elemental concentrations in the solid phase, and did not reflect cumulative trends associated with anthropogenic enrichment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00940126
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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