Description: Das Projekt "Oxygen depletion in a deep perialpine lake" wird/wurde gefördert durch: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung. Es wird/wurde ausgeführt durch: School of Architecture, Civil and Environmental Engineering (ENAC), Environmental Engineering Institute (IIE), Laboratory of Physics of Aquatic Systems (APHYS).With this project we seek three years of support for a PhD study for quantifying the hypolimnetic oxygen (O2) depletion in Lake Geneva. This project builds on results from an earlier project 'Turbulence and Fluxes in Natural Waters (200020-120128)', where we have been able to measure O2 fluxes to the sediment by applying the microprofiling and eddy-correlation techniques and to relate these fluxes to the forcing by bottom boundary layer (BBL) currents. Additionally, it is an extension of the O2 depletion model recently proposed by the Eawag team (Müller et al 2012). In this new project, we will expand the approach of water-sediment interface fluxes via applications to much larger, more complex and more strongly forced hypolimnia than have been previously studied. The choice of the field-site Lake Geneva is due to (i) the occurrence of the highest hypolimnetic O2 depletion rates measured in Switzerland, (ii) the access to a rich data-set dating back to 1957, (iii) the proximity of the sites and the availability of infrastructure, (iv) the acquired knowledge on the physical forcing of Lake Geneva and (v) the intended build-up of collaboration with Institute FA Forel and CIPEL. Besides the resources requested from SNSF, this project will be additionally supported by (i) the external senior researchers involved, (ii) a post-doc / junior researcher and (iii) the utilization of newly-acquired equipment (microprofiler, ADCPs, CTD and TDO sensors; the latter two will be financed by the new Chair in 'Physics of Aquatic Systems' at EPFL. The aim of this project is to develop a data-based model for the quantification of hypolimnetic O2 depletion in large and complex hypolimnia derived from measured and modelled fluxes from the water column through the diffusive boundary layer (DBL) to the sediment (FW-S: mineralization of organic matter at the sediment surface) and measured fluxes of reduced substances (FS-W: oxygen-equivalents) from the sediment to the water. The hypolimetic O2 consumption is then estimated by FW-S + FS-W (g O2 m-2 d-1). Local budgets will be performed in the BBL and in lake-wide layers as a function of depth (z). After a conceptual test of this model was found to be successful for a large number of vertically integrated hypolimnia (Müller et al 2012), we intend to expand upon these results by studying time series of O2 depletion as a function of z. Based on data to be obtained during a two-year period of fieldwork in Lake Geneva, we will conduct process studies quantifying the two fluxes FW-S and FS-W and use the data to calibrate this oxygen model. The hydrodynamic modelling will be used to extrapolate the effect of wind for the last 55 years. We hypothesize that this oxygen model will allow interpreting O2 depletion in most of the large lakes on earth. usw.
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Origins: /Bund/UBA/UFORDAT
Tags: Ammonium ? Genfer See ? Hydrodynamik ? Seen ? Gewässerbelastung ? Seensediment ? Sensor ? Temperaturverteilung ? Wind ? Gelöster Sauerstoff ? Hypolimnion ? Methan ? Organisches Material ? Zeitreihenanalyse ? Tiefenwasser ? Konsum ? Architektur ? Daten ? Jahreszeit ? Kausalzusammenhang ? Mineralisation ? Quantitative Analyse ? Sauerstoffgehalt ? Seenschichtung ? Standortwahl ? Studie ? Umwelttechnik ? Wasserinhaltsstoff ? Zeitreihe ? Sediment ? Algen ? Schule ? Stoff ? Modellierung ? Biologischer Abbau ? Messung ? Diffusion ? Grenzschicht ? in situ ? Ressource ? Wasseroberfläche ? Wasserstand ? Gewässer ? Abbau ? Chemischer Stoff ? Sauerstoffmangel ? bottom boundary layer ? Sauerstoffbedarf ? Sauerstoffverbrauch ? diffusive boundary layer ? lakes and reservoirs ? modelling of currents ? reduced substances flux ? Fluss [Bewegung] ? Aquatische Biomasse ? See [Binnengewässer] ? Wassermikroorganismen ? Dichtegradient ? microsensors ? Austauschprozess ?
License: cc-by-nc-nd/4.0
Language: Englisch/English
Time ranges: 2013-07-01 - 2016-06-30
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