Das Projekt "A8:Transporte und Flüsse durch die Bodengrenzschicht" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR) durchgeführt. The major goal of this new subproject is to estimate transport and fluxes of solutes between the bottom boundary layer, the stratified interior ocean and the ocean mixed layer on the continental slope and shelf regions of the Peruvian and Mauritanian Oxygen Minimum Zones (OMZ). The objectives will be achieved by estimating diapycnal and advective fluxes using two different methodological approaches: The first is basedon the measurement of the radium isotope distribution in sediments and in the water column. The second approach will use a combination of oceanographic measuring systems for the determination of turbulences, currents and hydrography. Subproject A8 will contribute to the understanding of the solute budget of the OMZ's and establishes a link between the benthic and pelagic research foci within the SFB 754.
Das Projekt "Transport of EINP through soil affected by the dynamics of infiltration flux and particle properties" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Umweltforschung GmbH - UFZ, Department Bodenphysik durchgeführt. In this project we experimentally explore the transport of engineered inorganic nanoparticles (EINP) through soils. This is done for original EINPs and some pre-aged form. Transport of NPs in soil is expected to be different from that of reactive solutes, in that hydrodynamic drag, inertial and shear forces as well as the affinity to water-gas interfaces are expected to be more relevant. Hence, the mobility of EINPs in soil is highly sensitive to the morphology of the porous structure and the dynamics of water saturation.This project provides the pore network structure for natural soils using X-ray micro-tomography to allow for an up-scaling of pore-scale interactions explored by project partners to the scale of soil horizons. The pore structure is represented by a network model suitable for pore scale simulations including the dynamics of water-gas interfaces.Pore network simulations will be compared to column experiments for conservative tracers as well as for unaltered and pre-aged EINPs (obtained from INTERFACE). This includes steady state flow scenarios for saturated (ponding) and unsaturated conditions as well as for transient flow to explore the impact of moving water-gas interfaces. The final goal is to arrive at a consistent interpretation of experimental findings and numerical simulations to develop a module for modelling EINP transfer through soil as a function of particle properties, soil structural characteristics and external forcing in terms of flux boundary conditions.
Das Projekt "Redox processes along gradients" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Lehrstuhl für Hydrologie, Limnologische Forschungsstation durchgeführt. The relevance of biogeochemical gradients for turnover of organic matter and contaminants is yet poorly understood. This study aims at the identification and quantification of the interaction of different redox processes along gradients. The interaction of iron-, and sulfate reduction and methanogenesis will be studied in controlled batch and column experiments. Factors constraining the accessibility and the energy yield from the use of these electron acceptors will be evaluated, such as passivation of iron oxides, re-oxidation of hydrogen sulfide on iron oxides. The impact of these constraints on the competitiveness of the particular process will then be described. Special focus will be put on the evolution of methanogenic conditions in systems formerly characterized by iron and sulfate reducing condition. As methanogenic conditions mostly evolve from micro-niches, methods to study the existence, evolution and stability of such micro-niches will be established. To this end, a combination of Gibbs free energy calculations, isotope fractionation and tracer measurements, and mass balances of metabolic intermediates (small pool sizes) and end products (large pool sizes) will be used. Measurements of these parameters on different scales using microelectrodes (mm scale), micro sampling devices for solutes and gases (cm scale) and mass flow balancing (column/reactor scale) will be compared to characterize unit volumes for organic matter degradation pathways and electron flow. Of particular interest will be the impact of redox active humic substances on the competitiveness of involved terminal electron accepting processes, either acting as electron shuttles or directly providing electron accepting capacity. This will be studied using fluorescence spectroscopy and parallel factor analysis (PARAFAC) of the gained spectra. We expect that the results will provide a basis for improving reactive transport models of anaerobic processes in aquifers and sediments.
Das Projekt "Release of hexavalent chromium from ore processing residues and the potential of biochar for chromium immobilization in polluted soils" wird vom Umweltbundesamt gefördert und von Universität Köln, Fachgruppe Geowissenschaften, Geographisches Institut durchgeführt. Chromium (Cr) is introduced into the environment by several anthropogenic activities. A striking ex-ample is the area around Kanpur in the Indian state of Uttar Pradesh, where large amounts of Cr-containing wastes have been recently illegally deposited. Hexavalent Cr, a highly toxic and mobile contaminant, is present in significant amounts in these wastes, severely affecting the quality of sur-roundings soils, sediments, and ground waters. The first major goal of this study is to clarify the solid phase speciation of Cr in these wastes and to examine its leaching behavior. X-ray diffraction and synchrotron-based X-ray absorption spectroscopy techniques will be employed for quantitative solid phase speciation of Cr. Its leaching behavior will be studied in column experiments performed at un-saturated moisture conditions with flow interruptions simulating monsoon rain events. Combined with geochemical modeling, the results will allow the evaluation of the leaching potential and release kinetics of Cr from the waste materials. The second major goal is to investigate the spatial distribution, speciation, and solubility of Cr in the rooting zone of chromate-contaminated soils surrounding the landfills, and to study the suitability of biochar as novel soil amendment for mitigating the deleterious effects of chromate pollution. Detailed field samplings and laboratory soil incubation studies will be carried out with two agricultural soils and biochar from the Kanpur region.
Das Projekt "Biometric tools for microarrays" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Kulturpflanzenwissenschaften (340), Fachgebiet Düngung und Bodenstoffhaushalt (340i) durchgeführt. Gene-expression data from microarrays open up a wide range of options for understanding gene action in general and heterosis in particular. Typically, many 1.000 genes are spotted on a microarray and screened for differential expression, while the number of replicates is often limited due to budget constraints, so the number of variables by far exceeds that of replications and the danger of over-fitting is even larger than in conventional QTL mapping. Also, expression data are influenced by a myriad of sources of random variation, thus obscuring the underlying pattern of expression. In light of these difficulties, realistic modelling that takes into account all sources of variation is of paramount importance. This project will develop a general mixed modelling and model selection framework for this task. A crucial question in the early stages of analysis is the choice of data transformation. While the log-transformation has been frequently used because of its simple interpretation with respect to fold change, others have been suggested. This project will explore the properties and suitability of different transformations. In addition multiplicative and factor-analytic models will be included to account for scale differences among different genes. Particular emphasis will be given to accounting for all relevant sources of error variation (dyes, slides, rows an columns, replications, field and laboratory trial variation, etc.). Finally, models for explaining and predicting heterosis will be integrated into the general modelling framework.
Das Projekt "Exzellenzcluster 80 (EXC): Ozean der Zukunft" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), Forschungsbereich 2: Marine Biogeochemie, Forschungseinheit Biogeochemische Modellierung durchgeführt. We propose to develop a computationally efficient way of coupling benthic and pelagic components of biogeochemical ocean and climate models. Neural network-based techniques are to be employed in order to provide the biogeochemical ocean model component with benthic boundary conditions that are consistent with its spatially and temporally varying simulated watercolumn properties. In this novel approach, the neural network associates actual bottom-water properties and sedimentation fluxes simulated by the water column model with consistent local steady-state fluxes of biogeochemical tracers across the sediment surface. This concept does not require long spin-up simulations of the coupled benthic-pelagic models over tens of thousands of years, and instead relies on previous training of the neural net s associative mapping capacity by a large number of long, computationally inexpensive, runs of a one-dimensional benthic model under varying bottom-water and sedimentation-flux conditions.
Das Projekt "Schaeden durch Verkehrsunfaelle an Laubbaeumen" wird vom Umweltbundesamt gefördert und von Pflanzenschutzamt Berlin durchgeführt. Untersuchungen zur Auswirkung von Anfahrschaeden (Verkehrsunfaelle) bei Baeumen. Anfaenglichen Rindenschaeden folgen ausgedehnte Stammfaeulen mit Einschraenkungen der Verkehrssicherheit.
Das Projekt "Räumlich-zeitlliche Verteilungsmuster von Plankton in Seen: Abiotische Störungen und organische Interkationen mit dem besonderem Fokus auf Planktothrix rubescens" wird vom Umweltbundesamt gefördert und von Universität Konstanz, Limnologisches Institut durchgeführt. The aim of the project is to investigate the role of physical forcing, resource availability, and organismic interactions for the spatial and temporal distribution patterns of plankton in lakes. The research is focused on the distribution patterns of the buoyant cyano bacterium Planklothrix rubescens in Lake Ammer and compares the abundance of P. rubescens with the temporal and spatial variability of abiotic conditions and of phyto- and zooplankton. The main hypotheses are that (1) transport by internal wave motions has a substantial influence on the horizontal distribution patterns of P. rubescens and also affects the distribution of other phyto- and zooplankton; (2) vertical water column motions associated with internal waves cause fluctuations in the vertical layering of P. rubescens and thus alters its competitive abilities; (3) horizontal differences in habitat conditions, i.e. limited vertical water column depth in bays and resource gradients near river inflows, result in longer-term characteristic horizontal distribution patterns of P. rubescens and other plankton; (4) layers of toxic P. rubescens may interfere with the vertical migration of zooplankton. These research questions will be addressed in extensive field experiments measuring horizontal and vertical distribution patterns of plankton and abiotic conditions at temporal scales ranging from minutes to several weeks. In-situ measuring techniques for plankton and abiotic parameters, providing sufficient teniporal and spatial resolution, will be combined with water sample analyses to support them. The distribution of P. rubescens will be measured by using our newly developed in-situ technique that combines information from optic and acoustic instruments. The field experiments will be complemented with 3D and 1D model approaches. The intension of the modeling work is to support the interpretation of the field data by performing numerical experiments that investigate the response of horizontal distribution patterns of P. rubescens to physical forcing, patchy nutrient distribution (e.g. river inflow) or the presence of a shallow bay and by studying the implications of water column depth, internal wave induced fluctuations in light intensity, and grazing for the layering of p. rubescens in a vertical water column.
Das Projekt "Mikrobieller Metabolismus von Modellpestiziden in der Drilosphäre und Einfluss auf die N2O-Bildung: Verknüpfung von Prozessen mit Populationen" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Fachgruppe Biologie, Bayreuther Zentrum für Ökologie und Umweltforschung (BayCEER), Lehrstuhl für Ökologische Mikrobiologie durchgeführt. Der Einsatz von Pestiziden ist in der Landwirtschaft weit verbreitet. Mineralisierung von Pestiziden findet im Boden hauptsächlich durch aerobe mikrobielle Prozesse statt. Bereiche hoher mikrobieller Aktivität im Boden schließen die Drilosphäre mit ein, d.h. Gänge, Darminhalt und Kot von Regenwürmern. Das Treibhausgas Distickstoffmonoxid (N20) wird in der Drilosphäre durch die dort ablaufenden Nitrifikation und Denitrifikation gebildet, welche von Pestiziden beeinflußt werden können. Allerdings sind die physikalisch-chemischen Parameter, aerobe und anaerobe Pestizid Abbauwege, sowie die Pestizid-abbauenden Mikroorganismen in der Drilosphäre nur wenig untersucht. Der Einfluß von Pestiziden und deren Abbauprodukte auf die Nitrifikation und Denitrifikation in der Drilosphäre sind größtenteils unbekannt. Daher sollen die folgenden Hypothesen mit Hilfe von Regenwürmer-enthaltenden Bodensäulen getestet werden: (i) In der Drilosphäre kommen bislang unbekannte, hoch aktive Prokaryotcn vor, die Phenoxyessigsäure Herbizide und deren Abbauprodukte umsetzen; und (ii) Phenoxyessigsäure-Herbizide und deren Abbauprodukte inhibieren die N20-Bildung und das Wachstum von bislang unbekannten Nitrifikanten und Denitrifikanten in der Drilosphäre. Zwischen- und Abbauprodukte sollen mit Hilfe von Gaschrornatographie (GC) und Hochdruckflüssigkeitschromatographie- Massenspektrometrie (H PLC-MS) bestimmt werden. 16S rRNA und mRNA basiertes 'Stable Isotope Probing', Quantifizierung funktioneller Gene mittels quantitativer 'real time' PCR (qPCR), 'Most Probable Number' (MPN) Analysen und zielgerichtete Isolierungsmethoden sollen zur Identifikation und Charakterisierung der prozeß-assoziierten, mikrobiellen Populationen und Mikroorganismen eingesetzt werden
Das Projekt "Beobachtungen ueber die Auswirkungen von Faeuleschaeden nach Rueckeverletzungen in jungen Fichtenbestaenden" wird vom Umweltbundesamt gefördert und von Technische Universität München, Holzforschung München durchgeführt. Aus je zwei, 1973 im Forstamt Kelheim angelegten, sommer- und wintergerueckten Versuchsflaechen wurden 54 bzw 132 rueckgeschaedigte Baeume mit insgesamt 239 Wunden gefaellt, auf Wundfaeule untersucht sowie deren hierdurch bedingte Entwertung berechnet. Die im Saft verletzten Baeume wiesen gegenueber jenen ausser Saft fast doppelt so grosse Verletzungen und deutlich staerkere Wundfaeule auf. Als Einflussfaktoren auf die Faeuleausbreitung wurden Wundalter, die Wundgroesse, die Schadenslage am Stamm, die durchschnitliche Jahrringbreite sowie der Faeule-Abschottungstyp nach Hugo (1979) festgestellt. Als wichtigster Faeuleerreger erwies sich Stereum sangninolentum.
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