649 research outputs found

    Numerical simulation of growth of Escherichia coli in unsaturated porous media

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    A model for the aerobic and anaerobic growth of Escherichia coli (HB101 K12 pGLO) depending on the concentration of oxygen and DOC as substrate has been developed based on laboratory batch experiments. Using inverse modelling to obtain optimal sets of parameters, it could be shown that a model based on a modified double Contois kinetic can predict cell densities, organic carbon utilisation, oxygen transfer and utilisation rates for a large number of experiments under aerobic and anaerobic conditions with a single unique set of parameters. The model was extended to describe growth of E. coli in unsaturated porous media, combining diffusion, phase exchange and microbiological growth. Experiments in a Hele-Shaw cell, filled with quartz sand, were conducted to study bacterial growth in the capillary fringe above a saturated porous medium. Cell density profiles in the Hele-Shaw cell were predicted with the growth model and the parameters from the batch experiments without any further calibration. They showed a very good qualitative and quantitative agreement with cell densities determined from samples taken from the Hele-Shaw cell by re-suspension and subsequent counting. Thus it could be shown, that it is possible to successfully transfer growth parameters from batch experiments to porous media for both aerobic and anaerobic conditions.Comment: Minor changes in conclusions, results unchange

    Methoden der Raumanalyse, naturwissenschaftliche

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    Naturwissenschaftlich geprägte Raumanalysen beschäftigen sich mit Geofaktoren (Geologischer Bau, Relief, Boden, Gewässer, Klima, Bios) in unterschiedlichen Maßstabsbereichen, erfassen ihre Anordnung im Raum, ihre Wechselbeziehungen und zeitlichen Veränderungen, wofür sie sich eines Methodenspektrums aus zahlreichen Wissenschaftsdisziplinen (u. a. Landschaftsökologie, Bodenkunde, Hydrologie, Vegetationskunde) bedienen

    Ökosystemdienstleistungen

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    Für die dem Menschen dienlichen Leistungen der Natur hat sich der Begriff Ökosystemdienstleistungen etabliert. Auf der Basis des entsprechenden Konzepts sollen ökologische Leistungen (Gratis-Naturkräfte) besser in Entscheidungsprozessen berücksichtigt und eine nachhaltige Landnutzung gewährleistet werden
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