Showing papers by "Swiss Federal Institute of Aquatic Science and Technology published in 1980"
TL;DR: In this paper, a series of polycyclic aromatic hydrocarbons (PAH) derived by early-diagenetic transformations of biogenic precursors are found in Recent sediments of four lakes ( Lake Lucerne, Lake Zurich, Lake Greifensee, and Lake Washington, northwest U.S.A.).
654 citations
01 Mar 1980
TL;DR: The best sediment trap for limnology is a simple cylinder with a diameter of from 5 to 20 cm and aspect ratio of greater than 5 for small lakes and greater than 10 for more turbulent water bodies.
Abstract: The published literature on the use of sediment traps has been reviewed and used to validate the conclusions of a theoretical analysis of the physical factors affecting the trapping of particles. Both practical and theoretical considerations lead us to recommed that the ‘best’ sediment trap for use in limnology is a simple cylinder with a diameter of from 5 to 20 cm and aspect ratio (ratio of length to diameter) of greater than 5 for small lakes and greater than 10 for more turbulent water bodies. We also demonstrate the need to know the approximate particle Reynolds number of particles being collected by sediment traps. A number of considerations lead us to advise against the use of collars, lattices, baffles, lids or refeence chambers. Recommendations are made on minimizing the unresolved problem of mineralization of organic material and on optimum length of exposure times, mooring systems, trap holding frames and sample handling.
393 citations
TL;DR: In this paper, polycyclic aromatic hydrocarbons (PAH) in sediment cores from Lake Lucerne, Lake Zurich, and Greifensee, Switzerland, and Lake Washington, northwest U.S.A.
387 citations
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TL;DR: The geochemistry of sulfur is to a great extent affected by the biosphere and living organisms transform sulfur from one oxidation state to another, thus changing the chemical properties of sulfur compounds and their distribution in the atmosphere, soils, waters and sediments.
Abstract: The geochemistry of sulfur is to a great extent affected by the biosphere. Living organisms transform sulfur from one oxidation state to another, thus changing the chemical properties of sulfur compounds and their distribution in the atmosphere, soils, waters and sediments.
28 citations
TL;DR: In this article, high performance liquid chromatography proved to be a valuable analytical tool, in conjunction with glass-capillary gas chromatography, in elucidating structures of the natural PAH.
Abstract: Recent sediments from Greifensee, Switzerland, and Lake Washington, northwest U.S.A., were analyzed for polycyclic aromatic hydrocarbons (PAH) with the purpose of understanding better the diagenetic formation of aromatic hydrocarbons in the Recent aquatic environment. High performance liquid chromatography proved to be a valuable analytical tool, in conjunction with glass-capillary gas chromatography and gas chromatography-mass spectrometry, in elucidating structures of the natural PAH. Greifensee contained only a pair of triaromatic-tetracyclic PAH, whereas Lake Washington contained a wide range of tetracyclic and pentacyclic compounds with two, three and four aromatic rings.
20 citations
01 Mar 1980
TL;DR: In this paper, a mathematical model is presented describing the vertical concentration gradient of a chemical species in the sediments of a lake as a function of external input variation and of characteristic parameters (mass sedimentation rate or sinking velocity, distribution factor between dissolved and particulate phase, hydraulic loading).
Abstract: A mathematical model is presented describing the vertical concentration gradient of a chemical species in the sediments of a lake as a function of external input variation and of characteristic parameters (mass sedimentation rate or sinking velocity, distribution factor between dissolved and particulate phase, hydraulic loading). Delayed response of external input variations on sedimentation due to finite species residence times is taken into account. The model is tested for Pb, Cd, Cu, and Zn in Greifensee (Switzerland) where—based on sediment data—an increase of external input of these metals by a factor 2.5 (Pb, Cd, Cu) and 4 (Zn) is found for the last 35 years.
12 citations
01 Jan 1980
TL;DR: In this article, a simple model of the activated sludge process is developed which takes into account the removal of soluble as well as particulate organic material, and the significance of the particulate organics with regard to diurnal variation of oxygen requirements is discussed.
Abstract: A simple model of the activated sludge process is developed which takes into account the removal of soluble as well as particulate organic material. The model allows prediction of the apparent activated sludge yield coefficient and the activated sludge nutrient content. The significance of the particulate organic material with regard to diurnal variation of oxygen requirements is discussed. Data from large scale (approximately 100 m3/d) activated sludge pilot plants serves to verify the model.
9 citations
01 Jan 1980
5 citations
01 Sep 1980
TL;DR: In this article, the mean y0, the amplitude A, and the phase t0 of the periodic regression function y(t)=y0+(A/2)sin[(t−t0)2π/T] is shown for the case of known period length T. The theory is exemplified using stream temperature measurements and applicability of the method to other limnological data, such as oxygen content is briefly discussed.
Abstract: The calculation of the mean y0, the amplitude A, and the phase t0 of the periodic regression function y(t)=y0+(A/2)sin[(t−t0)2π/T] is shown for the case of known period length T. An error estimation gives valuable information on how to plan efficient research programs. The theory is exemplified using stream temperature measurements. Applicability of the method to other limnological data, such as oxygen content is briefly discussed.
2 citations