Seasonal delivery of the particulate forms of phosphorus to Lake Geneva from the upper Rhone river   总被引：1，自引：0，他引：1  

D. Burrus  R. L. Thomas  J. Dominik  J. P. Vernet 《Aquatic Sciences - Research Across Boundaries》1990,52(3):221-235

Large volume water samples were taken at Porte du Scex and Bouveret at the mouth of the Upper Rhone River as it enters Lake Geneva. Samples were taken every two weeks during 1982 up until August 1983. Water samples were analyzed for total phosphorus (TP), and soluble reactive phosphorus (SRP) and were centrifuged in the field using a continuous flow centrifuge to recover the suspended solids following sieving at 63 µm. The < 63 µm solids were analyzed for total particulate phosphorus (TPP), organic phosphorus (OP), apatite phosphorus (AP) and non apatite inorganic phosphorus (NAIP). The > 63 µm were similarly analyzed and the weight of total solids in both size fractions recorded. Results were compared throughout the period of record to the hydrograph situated at Porte de Scex. The annual cycle of the Rhone can be divided into a low turbidity, low flow winter period (SED 1) and high flow, high turbidity summer season designated (SED 2). Turbidity is well related to discharge. The > 63 µm sediment is mobilized at 200 m³ s^–1 and thereafter increases in concert with, though at a faster rate than, the < 63 µm fraction. The coarse fraction contains significant quantities of phosphorus and in 1982 accounted for 26% of the TPP loading. OP and NAIP are higher in SED 1 than in SED 2 though AP remains constant throughout the year. OP is believed to be driven primarily from point sources whereas NAIP, in addition to point sources, has secondary sources in spring and summer due to sheet erosion from the agricultural soils of the valley. Loadings of phosphorus were calculated by four methods which showed internal consistency though they were higher than previous estimates. Bioavailable phosphorus (BAP) was estimated to account for some 20% of the total phosphorus loading of some 1500 tonnes; BAP is here taken to be the sum of SRP and NAIP and is that portion of the phosphorus load believed to be available to generate phytoplankton growth.  相似文献   

Texture and sedimentation rates in Lake Geneva     

J. -P. Vernet  J. Dominik  P. Y. Favarger 《Environmental Geology》1983,5(3):143-149

Thirty two cores were collected from Lake Geneva sediments along one longitudinal and eight transverse profiles. Rates of sedimentation determined by¹³⁷Cs vary from 0.01 to 1.86 g cm⁻² y⁻¹. The average deposition rates in coastal and slope areas amounts to 0.37 g cm⁻² y⁻¹ in the Upper Lake (Grand Lac) and 0.12 g cm⁻² y⁻¹ in the Lower Lake (Petit Lac). In the deep basins, average rates of 0.13 and 0.05 g cm⁻² y⁻¹ were found for the Grand Lac and Petit Lac, respectively. The estimated mass of sediment deposited yearly outside of the principal deltas and turbidity current depositional areas is about 1.0 million tons (about 13% of the estimated total river load). One turbidite is clearly identified in the deepest, central lake area. There is little variation of surface sediment texture (mean grain size about 8–9μm) with the exception of delta areas. Since the beginning of the twentieth century, both carbonate and organic matter have increased as a result of lake eutrophication.  相似文献   

Zur Chronologie anthropogener Schwermetalle in den Sedimenten des Attersees (Österreich)     

Prof. Dr. German Müller  J. Dominik  H. G. Schröder  J. Schneider 《Mineralogy and Petrology》1983,31(3-4):193-206

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Sedimentation rate variations and anthropogenic metal fluxes into Lake Constance sediments     

J. Dominik  A. Mangini  F. Prosi 《Environmental Geology》1983,5(3):151-157

Sedimentation rates were determined by²¹⁰Pb in three sediment cores from the main basin of Lake Constance. Rates vary from 0.094 to 0.133 g cm^?2y^?1, in agreement with previous determinations. A constant radionuclide flux (CR) model reveals long-term, quasi-synchronous fluctuations of sedimentation rate on the basin-wide scale. On average, the rate of sedimentation remains much the same from the beginning of this century indicating little effect of human activity in the watershed on fine-silt sediment supply. The anthropogenic fluxes of Zn, Pb, and Cd in the three cores are compared and the application of²¹⁰Pb as a heavy metal tracer in Lake Constance is examined. It seems to be a very good tracer for Pb, moderately good for Zn and Cu, and not useful for Cd.  相似文献   

Projected robust shift of climate zones over West Africa in response to anthropogenic climate change for the late 21st century   总被引：1，自引：0，他引：1  

Mouhamadou Bamba Sylla  Nellie Elguindi  Filippo Giorgi  Dominik Wisser 《Climatic change》2016,134(1-2):241-253

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Local Multiscale Approximations of Geostrophic Oceanic Flow: Theoretical Background and Aspects of Scientific Computing     

Willi Freeden  Dominik Michel  Volker Michel 《Marine Geodesy》2005,28(4):313-329

In modern geoscience, understanding the climate depends on the information about the oceans. Covering two-thirds of the Earth, oceans play an important role. Oceanic phenomena are, for example: oceanic circulation; water exchanges between atmosphere, land, and ocean; or temporal changes of the total water volume. All these features require new methods in constructive approximation, since they are regionally bounded and not globally observable. This article deals with a new and alternative method of handling data with locally supported basis functions, modeling them in a multiscale scheme involving a wavelet approximation and presenting the main results for the dynamic topography and the geostrophic flow, e.g., in the Northern Atlantic. Further, it is demonstrated that compressional rates of the occurring wavelet transforms can be achieved by using of locally supported wavelets and investigating the signal distribution within different frequency bands.  相似文献   

Bioleaching potential of bacterial communities in historic mine waste areas     

Nida Amin  Dominik Schneider  Michael Hoppert 《Environmental Earth Sciences》2018,77(14):542

Microbial activity has the potential to alter all cultural heritage in mining and metallurgy, due to metal mobilization by leaching. This communication shows the consequences of the bioleaching ability of two natural enrichments on copper slag samples from a historic ore smelting site in Sangerhausen (Mansfeld, Südharz, Saxony-Anhalt, Germany). Enrichment cultures gained from mine drainage were dominated by either the iron and sulfur-oxidizing Acidithiobacillus ferrivorans, or by the iron-oxidizing Leptospirillum. During 35 days of bioleaching in media containing copper slag pulp, inoculated with these enrichments, the change in pH and solubilized metal concentrations of the systems were monitored. Both bacterial strains were completely different from each other in their pattern of pH variation and rates of metal solubilization. The maximum removal of Cu (1725 mg/l) and Zn (715 mg/l) from copper slag substrate was achieved with enrichment culture of A. ferrivorans SCUT-1. However, maximum Mn (207 mg/l), Pb (86 mg/l), and Ni (75 mg/l) removal was observed with enrichment culture of Leptospirillum strain YQP-1. Implications for metal mobilization along with alteration of artifacts from not only historic mining areas but also aspects of decontamination and remediation are discussed.  相似文献   

Spatial and temporal dynamics of suspended particles and E. coli in a complex surface-water and karst groundwater system as a basis for an adapted water protection scheme,northern Vietnam     

Richter  Dominik  Goeppert  Nadine  Zindler  Björn  Goldscheider  Nico 《Hydrogeology Journal》2021,29(5):1965-1978

Karst aquifers in subtropical regions are characterized by high variability of water availability and quality due to changes associated with rainy and dry seasons. An additional challenge for water management is the combination of surface-water and karst groundwater systems since high spatiotemporal dynamics cause high variability of water quality. In these cases, adapted protection strategies are required. In this study, a protection approach for the catchment of a river-water diversion point in a rural area in northern Vietnam is developed. The variability of water quality was evaluated by rainy and dry season synoptic surveys of suspended particles and microbial contamination at 49 sites and time series at three sets of paired sites under constant hydraulic conditions. The anthropogenic land-use activities in the catchment were mapped to identify potential contamination sources and to highlight the challenging combination of surface-water and karst groundwater management. The analyzed data indicate differences in water quality between the dry and rainy seasons and a higher influence on water quality from land use than from hydrologic conditions. Furthermore, the results suggest a high risk of contamination resulting from residential areas, agriculture, and livestock farming, and reveal the necessity of implementation of appropriate measures such as restricted farming and the hook-up of buildings to municipal sewage disposal. Finally, the data show that water quality can be improved by adjusting water withdrawals by the time of day. The applied methods can be transferred to other surface-water and karst groundwater systems in similar subtropical environments.

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Identification of stoichiometric iron-phosphorus colloids produced in a eutrophic lake     

Charles-Philippe Lienemann  Marc Monnerat  Janusz Dominik  Didier Perret 《Aquatic Sciences - Research Across Boundaries》1999,61(2):133-149

: Iron-rich colloids formed at the oxic-anoxic interface of a eutrophic lake (Lake Lugano; CH) were characterized by bulk chemical methods and analytical electron microscopy. Fractionation of raw waters showed that non-dissolved iron is particulate above the oxicline and mainly colloidal in the anoxic part of the hypolimnion, while non-dissolved ortho-phosphate is mostly colloidal through the water column. Because of these differences, filtration did not prove helpful for the determination of the role of iron-rich species in the scavenging of ortho-phosphate. On the other hand, analytical electron microscopy revealed that iron-rich nano-granules (ca. 50nm) are associated to the surface of bacterially produced fibrillar polysaccharides. Iron colloids in these complex entities contain important and constant amounts of phosphorus ([PO4]part:[Fe]part = 0.48 - 0.11, n = 1096 Fe-rich entities analyzed by electron microscopy), which suggests that phosphates are stoichiometrically incorporated into the hydrous iron oxide phase, with a tentative composition Fe2[OOH]1-x[(OH)3]x[PO4], during its genesis.  相似文献   

Ferric/ferrous iron ratios in sodic amphiboles: Mössbauer analysis, stoichiometry-based model calculations and the high-resolution microanalytical flank method     

Michael Enders  Dominik Speer  Walter V. Maresch  Catherine A. McCammon 《Contributions to Mineralogy and Petrology》2000,140(2):135-147

Although the electron microprobe has become the standard microanalytical tool in modern geosciences, conventional electron microprobe analysis does not allow determination of the valence states of elements such as Fe. The correct classification of minerals and interpretation of reaction microfabrics and grain zonation require high-quality information on ferric/ferrous ratios on a scale of micrometers. The flank method developed by Höfer et?al. (1994, Eur J Mineral 6:407–418) has revived new interest in electron-induced X-ray-spectroscopy to resolve oxidation states in minerals with high spatial resolution. We have recharacterized well-documented sodic amphiboles of the glaucophane–ferroglaucophane–riebeckite–magnesioriebeckite series by electron probe microanalysis and combined the microanalytical data with ferric/ferrous ratios from Mössbauer spectroscopy, Li data from bulk ICP-AES analysis and H₂O data from bulk Karl–Fischer titration. The combination of microanalysis and high-quality analysis on the bulk materials results in a data set that allows comparison of model-based stoichiometric calculations and the calibration of the high-resolution flank method. The calibration obtained allows ferric/ferrous ratios to be determined within an error of ±5%. We have found it necessary to apply an empirical correction for absorption phenomena. The advantages of the method must be weighed against the complex calibration procedures necessary and thus the flank method will probably not find use as a routine method. However, in cases where high-resolution data in terms of valence state are needed, the flank method will provide useful data on ferric/ferrous ratios down to minimum FeO_total content of 6–8 wt%.  相似文献