Das Projekt "Steady-State Dilution and Mixing-Controlled Reactions in Three-Dimensional Heterogeneous Porous" wird vom Umweltbundesamt gefördert und von Eberhard Karls Universität Tübingen, Zentrum für Angewandte Geowissenschaften (ZAG), Arbeitsgruppe Hydrogeology durchgeführt. Understanding transport of contaminants is fundamental for the management of groundwater re-sources and the implementation of remedial strategies. In particular, mixing processes in saturated porous media play a pivotal role in determining the fate and transport of chemicals released in the subsurface. In fact, many abiotic and biological reactions in contaminated aquifers are limited by the availability of reaction partners. Under steady-state flow and transport conditions, dissolved reactants come into contact only through transverse mixing. In homogeneous porous media, transverse mixing is determined by diffusion and pore-scale dispersion, while in heterogeneous formations these local mixing processes are enhanced. Recent studies investigated the enhancement of transverse mixing due to the presence of heterogeneities in two-dimensional systems. Here, mixing enhancement can solely be attributed to flow focusing within high-permeability inclusions. In the proposed work, we will investigate mixing processes in three dimensions using high-resolution laboratory bench-scale experiments and advanced modeling techniques. The objective of the proposed research is to quantitatively assess how 3-D heterogeneity and anisotropy of hydraulic conductivity affect mixing processes via (i) flow focusing and de-focusing, (ii) increase of the plume surface, (iii) twisting and intertwining of streamlines and (iv) compound-specific diffusive/dispersive properties of the solute species undergoing transport. The results of the experimental and modeling investigation will allow us to identify effective large-scale parameters useful for a correct description of conservative and reactive mixing at field scales allowing to explain discrepancies between field observations, bench-scale experiments and current stochastic theory.
Das Projekt "B 1.2: Efficient water use in limestone areas - Phase 2" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Bodenkunde und Standortslehre durchgeführt. The elevated areas of Northern Thailand highlands are inhabited by ethnic minorities. On the other hand, the Thai majority prefers the valley bottoms. Population growth of all groups, reforestation and commercialisation of agriculture lead to an increasing pressure on land and water resources. Therefore, intensified land and water use systems are desired which are resource conserving at the same time. Here, special problem areas are the karstic limestone catchments due to the limited of surface waters.Own pre-investigations together with subproject A1 have shown, that land use systems there are subsistence oriented and local farmers do not use irrigation. But they would like to develop such technology, especially in order to increase staple crop production (highland rice, maize). But lack of irrigation possibilities is also responsible for the lack of diversification of land use systems with respect to orchards. One possibility to increase staple crop yields is to prolong the vegetation period by use of water harvesting technologies. Aim of this project is to develop such low cost water harvesting technologies (together with subproject B3.1) based on a participatory approach and to model the effect of these on the water balance at the catchments scale. This will be done on the basis of the previous variability studies and should lead to model tools, which allow to evaluate ex ante SFB innovation effects on the water balance. The project area is the Bor Krai catchments. Here, weirs will be installed to quantify surface water availability. An investigation plot will be situated near the village of Bor Krai which serves for water balance measurements (TDR/densitometry) and at the same time as demonstration plot for the local community. Here water harvesting by means of filling the soils field capacity at the end of the rainy season by gravity irrigation in order to prolong the vegetation period will be researched. Through cropping of participatory evaluated varieties the crop yield should be increased. The water consumption of traditionally managed and dominant crops (including orchards) will be measured at three further sites in the catchment (TDR, tensiometer). The water balance of the soil cover in the karst catchment will be based on the coupling of a SOTER map with a water transport model. The data base will be completed by soil type mapping, spatially randomised collection of soil physical properties (texture, bulk density, infiltration, water retention curve) and determination of the ku-function at two representative sites. As project results the available water amount for irrigation purposes will be quantified. The effective use of this water reserve will lead to increased productivity of the dominant crops and limitations to orchard productivity will be reduced. (abridged text)
Das Projekt "Energy Storage for Direct Steam Solar Power Plants (DISTOR)" wird vom Umweltbundesamt gefördert und von Deutsches Zentrum für Luft- und Raumfahrt e.V., Institut für Technische Thermodynamik durchgeführt. Objective: Solar thermal power plants represent today's most economic systems to generate electricity from solar insulation in them-range in regions like the Mediterranean area. By demonstrating the feasibility of direct steam generation in the absorber pipes European industry and research institutions have gained a leading position in this technology area. A key element foray successful market penetration is the availability of storage systems to reduce the dependence on the course of solarinsolation. The most important benefits result from -reduced internal costs due to increased efficiency and extended utilisation of the power block-facilitating the integration of a solar power plant into an electrical grid-adoption of electricity production to the demand thus increasing revenues Efficient storage systems for steam power plants demand transfer of energy during the charging/discharging process at constant temperatures. The DISTOR project focuses on the development of systems using phase change materials (PCM) as storage media. In order to accelerate the development, the DISTOR project is based on parallel research on three different storage concepts. These concepts include innovative aspects like encapsulated PCM, evaporation heat transfer and new design concepts. This parallel approach takes advantage of synergy effects and will enable the identification of the most promising storage concept. A consortium covering the various aspects of design and manufacturing has been formed from manufacturers, engineering companies and research institutions experienced in solar thermal power plants and PCM technology. The project will provide advanced storage material based on PCM for the temperature range of 200-300 C adapted to the needs of Direct Steam generation thus expanding Europe's strong position in solar thermal power plants.
Das Projekt "Effects of nurse tree species on growth, environment and physiology of underplanted Toona ciliata (F. Muell.)" wird vom Umweltbundesamt gefördert und von Universität Freiburg, Waldbau-Institut durchgeführt. Toona ciliata (Australian red cedar) is highly valued for veneer and furniture production and endangered in its natural ecosystems due to exploitation. This work aims to improve the availability of this wood on the market and help reduce pressure on the species in its native environment. An afforestation project cultivating Toona ciliata was introduced to the study site in Misiones, Argentina. The local cultivation faces losses caused by drought and frost, because T. ciliata requires overstory protection when young. Consequently, Grevillea robusta, Pinus elliottii x Pinus caribaea, and Pinus taeda, nurse tree species which also produce sought-after wood were chosen to provide protection. One-year-old T. ciliata seedlings were planted underneath each of the six-year-old nurse species. An inventory after one year indicated that both survival and height increment were highest underneath G. robusta and lowest underneath P. elliottii x P. caribaea. In this study I am examining possible facilitation and competition mechanisms between the overstory and understory T. ciliata. Extensive empirical data collected over the course of 3 years will be utilized to project potential growth scenarios for several rotations using a computer based forest growth model.
Das Projekt "SP 1.4 Evaluation of nutrient and pollutant cycles of livestock production systems and manure management systems in the North China Plain" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Agrartechnik, Fachgebiet Verfahrenstechnik der Tierhaltungssysteme (440b) durchgeführt. The increasing specialization and intensification of the agricultural food production in the North China Plain is leading to restrictions in nutrients and production cycles at farm and regional levels. As a result, livestock production in the North China Plain is entailing serious environmental negative impacts related to manure surpluses and recycling of nutrients, mainly leading to problems associated with water, soil and air pollution. On the other side higher nutrient demands in the local crops is leading to the purchase of chemical or mineral fertilizers when local or on-farm nutrients are not available. Therefore, the efficient use of organic fertilizers not only depends on their availability in the farms, but also on their nutritional composition. Likewise, soil nutrient requirements and plant physiological needs have to be taken into consideration. Indeed, the closer the nutrient cycles and the lower the environmental negative impacts and farm losses are, the greater the chances for a more sustainable resource use in the North China Plain. In the context of the IRTG, aspects of livestock farming in production systems in terms of widely closed nutrients cycles will be integrated. The material flows in different animal husbandry systems will be analysed and the environmental impacts dependent on livestock farming techniques, farms operability and their respective management will be investigated. The applicability and effectiveness of the technical and organizational measures for the reduction of material losses and, the environmental burdens caused by livestock and manure mismanagement in the North China Plain will be reviewed. The benefits and profits for the local cropping systems as result of the application of organic fertilizers originated from livestock farming will be both, ecologically and economically, evaluated as an alternative to replace the use of mineral fertilizers.
Das Projekt "Einfluss von Dürre auf das Waldsterben in Europa und Westkanada (Water03 - IDDEC)" wird vom Umweltbundesamt gefördert und von Technische Universität München, Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt, Fachgebiet für Ökoklimatologie durchgeführt. While many forests and woodlands may be at increasing risk of climate-induced dieback, significant knowledge gaps remain in our understanding of the causes of climate-induced tree mortality. Recent publications underscore the critical importance of understanding the mechanisms that trigger plant mortality (Adams et al., 2009), particularly regarding features and traits that could be used as physiological indicators of tree death (McDowell et al., 2008). Alterations in wood formation and structure often occur prior to visual symptoms of crown decline. Thus, physiological, morphological, and anatomical traits related to xylem ('water-conducting pipes') may provide early-warning signals of drought-induced dieback. A better mechanistic understanding of drought-induced forest dieback would improve our ability to predict tree mortality and future changes in forest composition and coverage. The project aims at studying how drought episodes promote dieback via changes in xylem structure. Different genotypes of aspen (parkland region and the southern boundary of the boreal forest in western Canada), oak (Southern Europe) and pine (experiment) will be studied along gradients of moisture availability. Xylem-related traits that will be measured include ring-width, number of missing rings, quantitative wood anatomical structures (diameter and frequency of vessels/ tracheids, inter-vessel pit structure) as well as cavitation resistance, hydraulic conductivity, and water potentials.
Das Projekt "Effects of biochar amendment on plant growth, microbial communities and biochar decomposition in agricultural soils" wird vom Umweltbundesamt gefördert und von Forschungsinstitut für biologischen Landbau Deutschland e.V. durchgeführt. Biochar has a great potential to ameliorate arable soils, especially those that are low in organic matter due to intensive use or erosion. Biochar is carbonised organic material with high porosity that brings about changes in physical, chemical and biological soil functions. Biochar amended soils show a higher water and cation exchange capacity with reduced leaching and enhanced availability of plant nutrients. The microbial biomass in biochar amended soils is enhanced and more diverse. Biochar is stabilised organic material, which is likely to remain for hundreds of years in the soil. Photosynthetically fixed atmospheric CO2 stabilised in biochar may thus act as a direct carbon sink and help to mitigate climate change. As feedstock and production conditions produce different biochar qualities predictions of effects in soil need to consider biochar and soil properties case by case. To date biochar has been approved to ameliorate highly weathered tropical soils with positive effects on crop growth and yield. Distinct microbial groups were reported to be enhanced in soils but if this depends on the particular soil or biochar or a combination of both is an open question, especially in temperate climates. Likewise, it is not known if microorganisms colonising biochar surfaces are responsible for its mineralization or if they just use the new niches provided. The aim of the proposed project is to investigate the influence of two biochar types on soil-plant systems by determining i) soil nutrient availability, plant growth and nutrient uptake, ii) structure and function of soil microbial communities, iv) the decomposition and fate of biochar in soils. We will use two loessial soils from the well-known DOK-trial with different soil organic matter content. Other soils from the region will be selected to provide a wider range of soil quality, in particular pH. The biochars will be produced by pyrolysis and hydrothermal carbonization (HTC) from the C4-plant Miscanthus gigantea. Pyrolysis derived material has bigger pore sizes due to the evaporating gasses and is commonly alkaline, whereas the HTC derived biochar has a finer pore size, a much higher oxygen content and more acidic functional groups.
Das Projekt "Auswirkungen der Gewinnung von Schiefergas und Schieferöl auf die Umwelt und die menschliche Gesundheit" wird vom Umweltbundesamt gefördert und von Wuppertal Institut für Klima, Umwelt, Energie gGmbH durchgeführt. In dieser Studie werden die möglichen Auswirkungen des 'Hydraulic Fracturing' ('Hydrofracking', 'hydraulische Behandlung', 'Frac-Behandlung') auf die Umwelt und die menschliche Gesundheit untersucht. Die quantitativen Daten und die Angaben zu den qualitativen Auswirkungen stammen aus den USA, da die Schiefergas-Gewinnung in Europa noch in den Kinderschuhen steckt. In den USA kann man hingegen auf eine über 40-jährige Erfahrung zurückblicken, dort wurden bereits über 50 000 Bohrungen durchgeführt. Zudem werden die Treibhausgasemissionen mittels einer kritischen Prüfung der vorliegenden Literatur sowie anhand eigener Berechnungen bewertet. Die europäischen Rechtsvorschriften werden im Hinblick auf das Verfahren der hydraulischen Behandlung überprüft, und es werden Empfehlungen zu weiteren Arbeiten formuliert. Die potenziellen Gasvorkommen und die künftige Verfügbarkeit von Schiefergas werden im Lichte der derzeitigen herkömmlichen Gasversorgung und ihrer voraussichtlichen Entwicklung erörtert.
Das Projekt "Establishment and exploration of a gas ion source for micro-scale radiocarbon dating of glaciers and groundwater" wird vom Umweltbundesamt gefördert und von Universität Heidelberg, Institut für Umweltphysik durchgeführt. Recent progress in the operation of CO2 gas ion sources for accelerator mass spectrometer (AMS) 14C analysis on microgram-size samples opens a wide range of new applications in dating studies, e.g. for environmental and archeological applications. This proposal aims at implementing a gas ion source at the AMS system MICADAS at the Klaus-Tschira Laboratory of the Curt-Engelhorn-Zentrum für Archäometrie (CEZA) in Mannheim and to use this new capability for cutting-edge applications in environmental studies, namely the dating of small amounts of organic carbon contained in glacier ice and of specific organic compounds in ground water. Cold glaciers hold unique records on past climate and atmospheric composition. Mid-latitude ice cores furthermore enable reconstructions of recent ice chemistry changes, but cannot be dated by stratigraphic methods. For such ice bodies, only radiometric dating based on 14C analysis of organic matter contained in the ice matrix presently offers a reasonable dating potential in the late Holocene and beyond. The challenge of this approach lies in the very restricted availability of this matter, but the ability to analyse microgram samples of organic carbon from ice via a gas ion source should now enable reliable 14C dating of ice. Ground water constitutes an important water resource worldwide, especially in semi-arid regions, and in addition constitutes a useful climate archive. Dating of ground water by 14C in the dissolved inorganic carbon (DIC) is standard but problematic due to the complex carbonate geochemistry. Dating of ground water based on dissolved organic carbon (DOC) has been attempted with mixed success, but now the new analytical developments enable compound-specific 14C analyses of the various DOC components, offering the chance to identify compounds suitable for dating. This project is based on the extensive experience of the collaborating scientists in 14C analytics and applications as well as in the use of glacier ice and ground water as archives, including the development and application of 14C dating methods for these systems. It will establish 14C-measurements at the MICADAS AMS of the CEZA via a gas ion source on a routine base to analyse CO2-samples in the range of 5 to 40 microgram C at a precision down to 0,5 Prozent. By improving existing sample preparation techniques for glacier ice samples, reliable 14C values of the particulate and dissolved organic fractions from small (some 100 g) ice samples shall be obtained. This capability will be applied to constrain ages of cold, sedimentary glaciers as well as of small scale, cold Alpine congelation ice bodies. The project will further develop and test the tools required for micro-scale, compound-specific radiocarbon dating of ground water via its organic fraction. For this purpose, ground water samples from the Upper Rhine Graben area will be analysed, where extensive isotopic data, including DIC 14C values, are available for comparison.
Das Projekt "Biotic and abiotic factors that dive the function of microbial communities at biogeochemical interfaces in different soils (BAMISO)" wird vom Umweltbundesamt gefördert und von Helmholtz Zentrum München Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Abteilung für Umweltgenomik durchgeführt. Biogeochemical interfaces shape microbial community function in soil. On the other hand microbial communities influence the properties of biogeochemical interfaces. Despite the importance of this interplay, basic understanding of the role of biogeochemical interfaces for microbial performance is still missing. We postulate that biogeochemical interfaces in soil are important for the formation of functional consortia of microorganisms, which are able to shape their own microenvironment and therefore influence the properties of interfaces in soil. Furthermore biogeochemical interfaces act as genetic memory of soils, as they can store DNA from dead microbes and protect it from degradation. We propose that for the formation of functional biogeochemical interfaces microbial dispersal (e.g. along fungal networks) in response to quality and quantity of bioavailable carbon and/or water availability plays a major role, as the development of functional guilds of microbes requires energy and depends on the redox state of the habitat.To address these questions, hexadecane degradation will be studied in differently developed artificial and natural soils. To answer the question on the role of carbon quantity and quality, experiments will be performed with and without litter material at different water contents of the soil. Experiments will be performed with intact soil columns as well as soil samples where the developed interface structure has been artificially destroyed. Molecular analysis of hexadecane degrading microbial communties will be done in vitro as well as in situ. The corresponding toolbox has been successfully developed in the first phase of the priority program including methods for genome, transcriptome and proteome analysis.
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