API src

Found 141 results.

Stillgewässer

Lage und Bezeichnung der Stillgewässer im Herner Stadtgebiet

Congestion-clearing payments to passengers

This paper reports on a project that considers whether the goals of (de)congestion pricing could be achieved in whole or in part by incentivizing mode-shift rather than using charging to force it: buying rather than selling decongestion. The project developed a method for estimating the net present value of the costs and benefits of a permanent ITS-enabled program of paying people to travel as passengers rather than as drivers - to reduce existing congestion in a target corridor to a target maximum level of delay - taking into account the mix of the traffic and the potential impact of latent demand and induced trips. This is relevant for making better use of existing infrastructure (a "build nothing" alternative to expansion, but not a "do nothing" one), for decarbonizing transport, and in the run up to automated vehicles where the possibility exists that new infrastructure investments in the 1-20-year timeframe will become stranded assets under some future scenarios. The project incorporated: a thorough review of the literature; focus groups; and a survey in a case study corridor in California to test the theory, develop the method, and determine the likely costs and benefits. The main insights include 1) the significance of an ââą Ìintra-peak demand shiftââą Ì that would occur if congestion was removed; 2) the need for four major components in a congestion-clearing payments program: a) incentives to switch from driving to being a passenger, b) incentives to travel at less preferred times, c) park and ride/pool facilities near the bottleneck to ease the passenger switch, and d) some limitation on single-occupant vehicle travel in the peak-of-the-peak in order to reserve space for vehicles carrying passengers; and 3) the possible need for different land-use regulations in a successful ââą Ìpayments to passengersââą Ì environment where the amount of traffic might no longer be an obvious constraint for expanding the local economy. The case study benefit cost analysis delivers a benefit cost ratio of 4.5 to 1. © 2020 The Author(s)

Teilprojekt 8 (BUW-NF): Implementierung der BUW National Facility

Das Projekt "Teilprojekt 8 (BUW-NF): Implementierung der BUW National Facility" wird vom Umweltbundesamt gefördert und von Universität Wuppertal, Fachgruppe Physik, Institut für Atmosphären- und Umweltforschung durchgeführt. Das kürzlich gegründete Institut für Atmosphären- und Umweltforschung (IAU) der Universität Wuppertal (BUW) verfügt über mehr als 35 Jahre Fachwissen in der Untersuchung atmosphärischer Photooxidationsprozesse (atmosphärische Chemie) und Fernerkundungstechniken (atmosphärische Physik). QUAREC-ASC des IAU arbeitet unter genau definierten Druck-, Temperatur- und Photolysebedingungen und ermöglicht eingehende Untersuchungen homogener Gasphasenreaktionssysteme. Die Anlage ermöglicht qualitativ hochwertige Untersuchungen der Kinetik und der Mechanismen der Reaktionen der wichtigsten troposphärischen Oxidationsmittel (OH, NO3, O3, Halogenatome) mit flüchtigen organischen Verbindungen. Teile der QUAREC-Anlage wurden bereits erneuert und die QUAREC-ASC war daher zwischenzeitlich außer Betrieb. Um zu vermeiden, dass die Kammer über längere Zeiträume nicht verfügbar ist, soll der spätere Entwurf und Bau eines verbesserten Temperaturregelungssystems (TRS) ab 2021 beginnen. Darüber hinaus ist die Instrumentierung für die Überwachung und Steuerung wichtiger physikalischer Parameter wie relative Luftfeuchtigkeit, Druck und Temperatur mit neuen Sensoren geplant. Zur besseren Ausschöpfung des Potenzials der QUAREC-Anlage wird der vorhandene Pool an analytischen Instrumenten erweitert bzw. erweitert. Dies betrifft die Anschaffung von drei hochmodernen Massenspektrometern sowie den Entwurf und die Konstruktion eines CEAS-Systems (Cavity Enhanced Absorption Spectroscopy). Darüber hinaus werden die Messgeräte für NO und H2O2 (Peroxide) durch neue, hochempfindliche Nachfolgemodelle ersetzt. Die BUW plant, die QUAREC-Anlage durch die Entwicklung einer großvolumigen (30 m3) Teflonkammer mit dem Namen WUTASC (Wuppertal Teflon Atmospheric Simulation Chamber) zu erweitern und zu verbessern.

Forschergruppe (FOR) 1806: The Forgotten Part of Carbon Cycling: Organic Matter Storage and Turnover in Subsoils (SUBSOM)

Das Projekt "Forschergruppe (FOR) 1806: The Forgotten Part of Carbon Cycling: Organic Matter Storage and Turnover in Subsoils (SUBSOM)" wird vom Umweltbundesamt gefördert und von Universität Bochum, Geographisches Institut, Arbeitsgruppe Bodenkunde und Bodenökologie durchgeführt. We are currently facing the urgent need to improve our understanding of carbon cycling in subsoils, because the organic carbon pool below 30 cm depth is considerably larger than that in the topsoil and a substantial part of the subsoil C pool appears to be much less recalcitrant than expected over the last decades. Therefore, small changes in environmental conditions could change not only carbon cycling in topsoils, but also in subsoils. While organic matter stabilization mechanisms and factors controlling its turnover are well understood in topsoils, the underlying mechanisms are not valid in subsoils due to depth dependent differences regarding (1) amounts and composition of C-pools and C-inputs, (2) aeration, moisture and temperature regimes, (3) relevance of specific soil organic carbon (SOC) stabilisation mechanisms and (4) spatial heterogeneity of physico-chemical and biological parameters. Due to very low C concentrations and high spatio-temporal variability of properties and processes, the investigation of subsoil phenomena and processes poses major methodological, instrumental and analytical challenges. This project will face these challenges with a transdisciplinary team of soil scientists applying innovative approaches and considering the magnitude, chemical and isotopic composition and 14C-content of all relevant C-flux components and C-fractions. Taking also the spatial and temporal variability into account, will allow us to understand the four-dimensional changes of C-cycling in this environment. The nine closely interlinked subprojects coordinated by the central project will combine field C-flux measurements with detailed analyses of subsoil properties and in-situ experiments at a central field site on a sandy soil near Hannover. The field measurements are supplemented by laboratory studies for the determination of factors controlling C stabilization and C turnover. Ultimately, the results generated by the subprojects and the data synthesized in the coordinating project will greatly enhance our knowledge and conceptual understanding of the processes and controlling factors of subsoil carbon turnover as a prerequisite for numerical modelling of C-dynamics in subsoils.

Redox processes along gradients

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.

Der Phosphor-Kreislauf in Waldökosystemen nachvollzogen durch die Analyse des Isotopenverhältnisses des Sauerstoffs in Phosphat

Das Projekt "Der Phosphor-Kreislauf in Waldökosystemen nachvollzogen durch die Analyse des Isotopenverhältnisses des Sauerstoffs in Phosphat" wird vom Umweltbundesamt gefördert und von Universität Tübingen, Fachbereich Geowissenschaften, Forschungsbereich Geographie durchgeführt. Unsere konzeptionelle Sicht des P-Kreislaufes in Waldökosystemen beruht auf der Untersuchung von P-Pools, den Zusammenhängen zwischen verschiedenen P-Pools und zu einem geringen Anteil von P-Flüssen. Bisherige Arbeiten konnten aber nicht die Prozesse aufdecken, die ein Phosphatmolekül auf ökosystemarer Skala durchlief. Zum Beispiel sind die oben genannten Ansätze nicht geeignet, um zwischen der Freisetzung aus einem Mineral oder aus einer organischen Verbindung zu unterscheiden. Die Untersuchung des Sauerstoffisotopenverhältnisses in Phosphat könnte diese Informationen liefern. Unser Ziel ist es, die Wichtigkeit biologischer und geochemischer Prozesse, die den P-Kreislauf in 4 Waldökosystemen kontrollieren, entlang eines Gradienten der P-Verfügbarkeit im Boden zu untersuchen. Wir werden den Verbleib von Phosphat i) im Kreislauf vom Streufall-P über P-Freisetzung während des Abbaus organischer Substanz in der organischen Auflage und im Boden bis hin zur Aufnahme durch die Pflanzen und ii) während der Freisetzung aus P-haltigen Mineralen im Boden und der anschließenden Aufnahme in die Pflanzen verfolgen. Wir werden Mulit-Isotopenansätze (O im Wasser, P and O in Phosphat, C in der organischen Substanz) nutzen, die wir innovativ verbinden, um unsere Forschungsfragen zu beantworten. Für das tiefgreifende Verständnis des P-Kreislaufes während des Abbaus von organischer Substanz werden wir uns auf folgende experimentelle Ansätze stützen: i) Messungen in den etablierten Waldsystemen (Output 1), ii) Laborinkubationen der organischen Auflage und des Mineralbodens (Outputs 2 und 3) sowie iii) Topfexperimente mit wachsenden Pflanzen (Outputs 4 und 5). Unser Projekt wird zur Verifizierung der allgemeinen Hypothese des SPP-Programmes beitragen, dass die mit der Zeit sinkende P-Verfügbarkeit die Waldökosysteme von Mobilisierungs- (effiziente Mobilisierung aus der Mineralphase) zu Recycling-Systemen (sehr effizientes Recycling von P) verschiebt.

The effect of elevated atmospheric CO2 concentration on gross nitrogen dynamics, plant N-uptake and microbial community dynamics in a permanent grassland

Das Projekt "The effect of elevated atmospheric CO2 concentration on gross nitrogen dynamics, plant N-uptake and microbial community dynamics in a permanent grassland" wird vom Umweltbundesamt gefördert und von Universität Gießen, Institut für Pflanzenökologie (Botanik II) durchgeführt. To predict ecosystem reactions to elevated atmospheric CO2 (eCO2) it is essential to understandthe interactions between plant carbon input, microbial community composition and activity and associated nutrient dynamics. Long-term observations (greater than 13 years) within the Giessen Free Air Carbon dioxide Enrichment (Giessen FACE) study on permanent grassland showed next to an enhanced biomass production an unexpected strong positive feedback effect on ecosystem respiration and nitrous oxide (N2O) production. The overall goal of this study is to understand the long-term effects of eCO2 and carbon input on microbial community composition and activity as well as the associated nitrogen dynamics, N2O production and plant N uptake in the Giessen FACE study on permanent grassland. A combination of 13CO2 pulse labelling with 15N tracing of 15NH4+ and 15NO3- will be carried out in situ. Different fractions of soil organic matter (recalcitrant, labile SOM) and the various mineral N pools in the soil (NH4+, NO3-, NO2-), gross N transformation rates, pool size dependent N2O and N2 emissions as well as N species dependent plant N uptake rates and the origin of the CO2 respiration will be quantified. Microbial analyses will include exploring changes in the composition of microbial communities involved in the turnover of NH4+, NO3-, N2O and N2, i.e. ammonia oxidizing, denitrifying, and microbial communities involved in dissimilatory nitrate reduction to ammonia (DNRA). Stable Isotope Probing (SIP) and mRNA based analyses will be employed to comparably evaluate the long-term effects of eCO2 on the structure and abundance of these communities, while transcripts of these genes will be used to target the fractions of the communities which actively contribute to N transformations.

Koordinationsfonds

Das Projekt "Koordinationsfonds" wird vom Umweltbundesamt gefördert und von Universität Potsdam, Institut für Umweltwissenschaften und Geographie, Arbeitsgruppe Wasser- und Stofftransport in Landschaften durchgeführt. The exchange of water between atmosphere, biosphere, and hydrosphere can be viewed as a result of complex interactions of dynamic feedback mechanisms, where soil moisture content acts as the key state variable. Novel approaches are required to handle land surface complexity and scale dependency of water fluxes. State-of-the-art observations of soil moisture content are ranging from continuous point-scale measurements via field-scale snapshots to remote sensing products on the basin scale and beyond. They have to deal with a space-time trade-off since the measurement frequency typically decreases with the covered spatial scale. Thus, in spite of the use of hydrological models, our knowledge of soil moisture patterns, their dynamics, and the underlying processes, is still limited. We aim at bridging existing gaps between scales through additional techniques and sources of information about the soil water storage. Cosmic-ray neutron sensing (CRNS) measures the presence of water by sensing changes in neutron density above the ground. We will develop a quantitative, adaptable, and transferable approach for observing representative soil moisture content values on the field scale while accounting for other dynamic water pools on the land surface, such as biomass, interception, and snow. Furthermore, we will transfer the mapping of soil moisture to larger scales with sensor clusters and mobile neutron detectors. CRNS will function as a unique combination of invasive and non-invasive observations in joint field campaigns. The measurement and interpretation of soil moisture by CRNS requires advanced knowledge of soil hydrology as well as particle physics including neutron transport modeling. Engineering efforts will be made for detector development that aims to substantially improve the temporal resolution and spatial coverage. Ecohydrology is the life-science ingredient to determine the dynamic influence of vegetation and interception on the neutron signal, while catchment hydrology provides the framework for understanding water flow in soils and catchments. Our approach is especially tailored to resolve the discrepancy in support volume and timing between hydrological models and field observations. Comprehensive observations by CRNS, remote sensing and complementary methods will be used concertedly with hydrological and land-surface models at the regional scale to infer also groundwater recharge and atmospheric fluxes. Thereby, models and observations together will allow for identifying patterns and processes at the scale of small catchments with unprecedented spatio-temporal resolution. This research unit will strengthen an engaged and innovative community that constitutes a driving force in the field of soil moisture measurements via CRNS. Our team will provide an excellent and timely starting-point for advancing the frontier of understanding field-scale and regional water storage and fluxes in soil-vegetation-atmosphere systems.

Biogenic formation of non-extractable residues from pesticides in soil

Das Projekt "Biogenic formation of non-extractable residues from pesticides in soil" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Umweltforschung GmbH - UFZ, Department Umweltbiotechnologie durchgeführt. During microbial turnover of organic chemicals in soil, non-extractable residues (NER) are formed frequently. Studies on NER formation usually performed with radioisotope labelled tracer compounds are limited to localisation and quantitative analyses but their chemical composition is left unknown. Recently, we could show for 2,4-dichlorophenoxyacetic acid and ibuprofen that during microbial turnover in soil nearly all NER were derived from microbial biomass, since degrading bacteria use the pollutant carbon for their biomass synthesis. Their cell debris is subsequently stabilised within soil organic matter (SOM) forming biogenic NER (bioNER). It is still unknown whether bioNER are also formed during biodegradation of other, structurally different compound classes of organic contaminants. Therefore, agricultural soil will be incubated with labelled compounds of five classes of commonly used and emerging pesticides: organophosphate, phenylurea, triazinone, benzothiadiazine and aryloxyphenoxypropionic acid. The fate of the label will be monitored in both living and non-living SOM pools and the formation of bioNER will be quantified for each compound over extended periods of time. In addition, soil samples from long-term lysimeter studies with 14C-labelled pesticide residues (e.g. triazine, benzothiazole and phenoxypropionic acid group) will be also analysed for bioNER formation. The results will be summarised to identify the metabolic conditions of microorganisms needed for bioNER formation and to develop an extended concept of risk assessment including bioNER formation in soils.

Indonesian Throughflow variability on sub-orbital timescales during Marine Isotopes Stages (MIS) 2 and 3

Das Projekt "Indonesian Throughflow variability on sub-orbital timescales during Marine Isotopes Stages (MIS) 2 and 3" wird vom Umweltbundesamt gefördert und von Universität Kiel, Institut für Geowissenschaften, Abteilung Angewandte Geophysik durchgeführt. This project will provide quantitative estimates of the flow of low-salinity warm water through the Indonesian Gateway on suborbital timescales during MIS 2 and 3 (focusing on Dansgaard Oeschger (D-O) oscillations) and will assess the Indonesian Throughflow (ITF) s impact on the hydrography of the eastern Indian Ocean and global thermohaline circulation during this critical interval of high climate variability. ITF fluctuations, associated with sea level change, temperature and salinity variations in the West Pacific Warm Pool (WPWP) strongly influence precipitation over Australia, the strength of the southeast-Asian summer monsoon, and the intensity of warm meridional currents in the Indian Ocean. We will test the hypothesis that increased ITF is associated with warm interstadials of MIS 3, whereas a strong reduction in ITF occurred during stadials. We will use as main proxies planktonic and benthic foraminiferal isotopes in conjunction with Mg/Ca temperature estimates and radiogenic isotopes (mainly Nd) as tracers of Pacific water masses along depth transects in the Timor Passage and the eastern Indian Ocean. This project will provide the paleoceanographic framework that will be crucial to validate and refine circulation models of D-O events and high-frequency climate variability on a global scale.

1 2 3 4 5 … 13 14 15