Das Projekt "Energy and Water Fluxes at the Soil Atmosphere Interface of Water Repellent soils" wird vom Umweltbundesamt gefördert und von Technische Universität Berlin, Institut für Ökologie, Fachgebiet Bodenkunde durchgeführt. Unsere zentrale Arbeitshypothese ist, dass durch die globale Erwärmung nicht nur der Trend zur Hydrophobie von Böden zunehmen wird, sondern dass auch der Energieaustausch an der Grenzschicht Bode/Atmosphäre verändert wird und sich damit eine Rückwirkung auf das globale Klima ergibt. Um unsere Arbeitshypothese zu prüfen, beabsichtigen wir, alle Größen der Energie- und Wasserbilanz zwischen Boden und Atmosphäre für einen stark von Hydrophobie geprägten Boden zu bestimmen.
Das Projekt "Watershed sediment yield modelling for data scarce areas; a case study, Awash River Basin, Ethiopia" wird vom Umweltbundesamt gefördert und von Universität Stuttgart, Institut für Wasserbau durchgeführt. The main goal of the research was to device an alternative solution for watershed sediment yield modelling for data scarce areas where the existing physically based models can not be applicable. Awash River Basin in Ethiopia was selected as case study area. GIS data on soil, land use, precipitation, temperature, stream flow and suspended sediment yield was collected from the Federal Ministry of Water Resources of Ethiopia (FMWRE) and from the National Metrology Service Agency (NMSA) offices. Soil data obtained from FMWRE and Food and Agriculture Organization (FAO) world soil 1974 database was used for derivation of the soil erodibility factor (ERFAC) estimation equation. The ratio of silt to sand and clay content was considered as the governing factor for soil erodibility in developing the ERFAC equation. The SWAT2005 model was selected for calibration and validation of stream flow and sediment yield. A sensitivity analysis was carried out to prioritize model calibration parameters. From the sensitivity analysis, curve number II (CN2), soilwater available to plants (SOL-AWC) and ground water base flow factor (ALPHA-BF) were selected as major stream flow calibration parameters. Similarly CN2, SURLAG (surface lag), slope and sediment routing factor (SPCON) were taken as the major sediment calibration parameters. Parameters related to the soil properties and river channel characteristics were given special attention during the model calibration. Eleven years (1990-2000) stream flow and sediment data were used for model calibration and six years data (2001-2006) were used for model validation. Calibration has been done at three gauging stations located in the Awash River basin. The statistical indicators, Coefficient of determination (R2), Nash-Sutclife efficiency (NSE), Root mean square error observations standard deviation (RSR were applied to evaluate the calibration and validation results. The values of these indicators were used to ratethe performance of the model. Watershed geomorphologic and topographic factors were extracted from the SWAT2005 watershed configuration, using a GIS tool and empirical equations. The relative importance of the factors was determined using Pearsons correlation coefficient based on the sediment yield output obtained from the SWAT2005 model calibration. The results show that, the sediment yield is highly correlated with stream flow, watershed area and watershed slope. Based on the identified parameters and the SWAT2005 model output, an alternative sediment yield estimation equation was derived and checked for its validity.
Das Projekt "Estimating the energy balance over forests including advection and horizontal flux divergence" wird vom Umweltbundesamt gefördert und von Technische Universität Dresden, Bereich Bau und Umwelt, Fachrichtung Hydrowissenschaften , Institut für Hydrologie und Meteorologie, Professur für Meteorologie durchgeführt. One unsolved problem of the micrometeorological community is the unclosed energy balance when its components are independently measured in the field. This so-called energy balance closure gap was investigated with focus on sinks and sources (storage change terms) and on the uncertainties involved in the estimation of the available energy. The second main topic was the assessment of the non-turbulent fluxes of sensible heat and latent heat as well as the horizontal turbulent flux in case of sensible heat. These fluxes are commonly neglected as their assessment is difficult. The third main point was the comparison of advective fluxes of sensible heat and carbon dioxide with the aim to facilitate an easier assessment of the advective fluxes of carbon dioxide. Analyses were based on the ADVEX- and the MORE II-dataset. For the investigated sites it could be shown that the energy balance closure improved when the storage terms were carefully considered. An inspection of the uncertainties involved in the available energy revealed that these uncertainties cannot explain the lack of energy balance closure alone. An inclusion of the non-turbulent advective fluxes of latent heat and sensible heat changed the corresponding budgets and improved the energy balance closure partly. However, residuals did not vanish. The horizontal turbulent flux divergence of sensible heat turned out to be negligible for the investigated site and time period. The comparison of the non-turbulent advective fluxes of sensible heat and carbon dioxide showed that advective fluxes of both scalars are larger during night than during day and that they both share a considerable scatter. On a mean diurnal basis, the advective fluxes of sensible heat and carbon dioxide turned out to be of opposite sign especially during night.
Das Projekt "6. RP Aquaterra - Understanding river-sediment-soil-groundwater interactions for support of management of waterbodies (river basin & catchment areas) (AQUATERRA)" wird vom Umweltbundesamt gefördert und von Universität Tübingen, Institut für Geowissenschaften, Zentrum für Angewandte Geowissenschaften durchgeführt. 46 Partner arbeiteten in diesem EU-Projekt zusammen. Ziel war es, eine wissenschaftliche Basis zu erhalten, um die Bewirtschaftung eines Flussgebietes zu verbessern. Dabei stand das genaue Verständnis des Fluss-Sediment-Boden-Grundwasser Systems als Ganzes zu verschiedenen zeitlichen und räumlichen Modellen im Vordergrund. Das An-Institute arbeitete im MONITOR-Unterprojekt mit. Seine Aufgaben lagen in der Entwicklung und Validierung analytischer Methoden, um organische und anorganische Schadstoffe in Wasser-, Sediment- und Bodenkompartimente zu erfassen. Start dieses 5jährigen Projektes war am 01. Juni 2004.
Das Projekt "Application of Anaerobic Ammonium Oxidation in Mainstream Municipal Wastewater Treatment" wird vom Umweltbundesamt gefördert und von Technische Universität Darmstadt, Institut IWAR, Fachgebiet Abwasserwirtschaft durchgeführt. Nitritation combined with anaerobic ammonium oxidation (anammox) has been widely applied in treatment of high nitrogenous wastewaters since its discovery in the 1990s. This process is more cost efficient than conventional treatment technologies and has been studied intensively for municipal reject water or centrate treatment. Due to the slow growth rate of the involved microorganisms systems with high biomass retention such as biofilm reactors or granular based sequencing batch reactors (SBRs) are often employed. The current applications of nitritation-anammox processes are confined to wastewaters with ammonium concentrations of greater than 500 mg-N l-1 and temperatures around 30 C. Complete nitrogen removal without the need for organic carbon and in addition less energy consumption is, however, also highly interesting for mainstream municipal wastewater treatment. The main goal of this project is thus to realize the application of nitritation-anammox at low temperature/low substrate conditions with two different reactor types, SBR (suspended sludge system) and MBBR (biofilm reactor system). The key questions are the stabilization of the anammox reaction under these conditions on the one side and the minimization of unwanted nitrite oxidation on the other side. Stepwise reduction of ammonium loading and temperature will be used to acclimate the biomass to the desired condition. Oxygen limitation strategies and pH control will be applied as main regulatory instruments to sustain an optimal biomass composition and limit aerobic nitrite oxidation.
Das Projekt "Hydropower: Integrated environmental and economical modelling of tidal renewable energy production" wird vom Umweltbundesamt gefördert und von Universität Stuttgart, Institut für Wasserbau durchgeführt. The aim of this project is to address fundamental issues regarding the interaction of marine renewable energy devices with the flow and the environment and also to look at the economical implications of tidal energy extraction from the estuary and related environmental cost. This project brings together experts from two highly regarded civil engineering departments with a long track record in their respective areas of expertise, to provide answers to fundamental questions regarding marine renewable energy. Wales is well suited as a case study in the marine energy sector with considerable natural marine energy potential, a good base of heavy industrial companies to build devices, a number of relatively large ports with good facilities, strong university and governmental support, and a strong commitment to this area in the 'Wales Energy Route Map'. Several marine renewable concepts are in the planning stage around the Welsh coastline at present. A tidal barrage across the Bristol Channel and tidal stream turbines are the two most promising technologies and these two scenarios will be used as case studies in this project. In this study investigations will be carried out to ascertain how energy devices will impact on the water levels and velocities in the Bristol Channel which, in turn, will affect the suspended sediment concentration distributions, the general water quality characteristics and therefore the benthic ecology and the general hydro-ecology of the estuary. This will be achieved by: (a) refining Cardiff Universitys estuarine model DIVAST to predict the impact of a tidal barrage and operating tidal stream turbines on the hydrodynamic, sediment transport and water quality characteristic distributions in the Bristol channel, (b) refining Universität Stuttgarts CASiMiR, WASKRA and Input-Output modelling tools and approaches to assess the influences of new tidal energy structures on habitats, to describe the tidal energy production and dependencies between economical and ecological aspects of the system and (c) analysing and linking the output from all modelling approaches creating a generic integrated physical, environmental and economical impact assessment approach of tidal renewables.
Das Projekt "Isotope pathway from atmosphere to the tree ring along a humidity gradient in Switzerland" wird vom Umweltbundesamt gefördert und von Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft durchgeführt. Temperatures in Switzerland increased about 0.57 C over the last three decades and climate models predict that this increase will continue during the 21st century and beyond. Accompanied by changes in the water supply due to the expected increase in the frequency and intensity of heavy precipitation and/or drought events, these effects will strongly force changes in forest productivity, spatial distribution of tree species, and changes in the species composition within forests. Projections of the future dimensions and interactions of these effects require detailed understanding of short and long-term changes in eco-physiological responses to past and present climate variation. Stable isotopes in tree rings have become a significant tool in obtaining retrospective insight into the plant physiological response to climate and other environmental variables. The increasing number of isotope records, however, also highlights important unsolved questions and current limitations of this tree-ring parameter. Obviously, an improved understanding of the mechanisms leading to variations in the tree's internal carbon and water cycle in relation to climate, soil moisture conditions, transpiration and expansion of the root system is urgently needed. ISOPATH aims to decipher the origin and variability of the isotopic signal in the tree rings of two alpine species, frequently used in climate reconstructions, and to understand the environmental and physiological information encoded. We will develop weekly resolved records of carbon and oxygen isotopes in xylem and needle water, needle sugars, phloem sugars and stem wood/cellulose of two physiologically differing species (larch and spruce) growing under varying temperature, soil moisture and relative humidity conditions. Those data will be related to a large suite of external variables including precipitation and soil water, temperature, and vapour pressure deficit. We act (i) on a spatial scale by following the complete pathway of stable isotopes from the atmosphere into the tree ring under varying environmental conditions and (ii) on a temporal scale by studying seasonal cycles of the isotope signals in all these different components, covering four growth seasons (2008-2011). This unique dataset in terms of length, resolution and number of measured variables will be used to test and improve advanced models for isotope fractionation at the leaf level and in the tree ring, in relation to species-specific traits, temperature and soil moisture conditions. The measured and modelled isotope signatures will allow to predict plant physiological adaptation in the alpine environment to climate change of the 21st century.
Das Projekt "Understanding biomineralization and its implications for the environmental chemistry of selenium" wird vom Umweltbundesamt gefördert und von Fachhochschule beider Basel - Nordwestschweiz durchgeführt. Due to the tendency to bioaccumulate, trace concentrations of selenium in fresh waters have led to disastrous toxicity effects on water birds and fish in the past. Although this adverse impact was first noticed in the early 1980s, to date no sustainable solution has been found for the remediation of selenium contaminated drainage and waste waters. Compared to water soluble forms, elemental selenium is considered less toxic. Therefore, various remediation approaches try to use microorganisms that are highly efficient in reducing selenium oxyanion concentrations by formation of insoluble elemental selenium. Such biogenic elemental selenium, however, does not crystallize to large particles and remains dispersed in solution as a colloidal suspension, thus being subject to re-oxidation, uptake and assimilation by biota. The probable reason for the tendency of biogenic selenium to remain in solution suspended as nanoparticles is an organic polymer layer modifying the surface, preventing crystallization and conferring the selenium core with physico-chemical properties different from particles without such a layer. To date, it is not known, which molecules (proteins, (poly)saccharides, etc.) form this organic polymer layer. Consequently, it is furthermore unknown, if all microbial groups mediating selenium reduction (either via a respiratory or via co-metabolic reduction) produce the same organic polymer layer around the selenium core. The physico-chemical properties of the layer, however, will strongly influence sedimentation and transport processes of selenium in the environment. Due to the complex chemistry and the nanocrystalline character of the selenium particles, uncertainties persist concerning the selenium solid phase, which is formed biogenically. It is not known, if and to which extent selenium that bears such a polymers layer is subject to further biotic and abiotic oxidation and reduction processes, although these processes will largely govern the ecotoxicological effects of selenium. The present project aims at filling the gaps in understanding biogenic selenium formation by systematically investigating the morphology and speciation of the solid phase and the surface modification mechanisms. By direct (spectroscopic) methods we will determine selenium solid phase speciation and its transformations under environmental conditions. We will develop methods allowing the identification of the organic polymer layers modifying selenium nanoparticles by different microbial groups. Thus we will be able to deliver a mechanistic model describing both layer and core of biogenic selenium nanoparticles and the possible impact(s) they have on each other.
| Origin | Count |
|---|---|
| Bund | 8 |
| Type | Count |
|---|---|
| Förderprogramm | 8 |
| License | Count |
|---|---|
| open | 8 |
| Language | Count |
|---|---|
| Deutsch | 8 |
| Englisch | 8 |
| Resource type | Count |
|---|---|
| Keine | 7 |
| Webseite | 1 |
| Topic | Count |
|---|---|
| Boden | 8 |
| Lebewesen & Lebensräume | 8 |
| Luft | 6 |
| Mensch & Umwelt | 8 |
| Wasser | 8 |
| Weitere | 8 |