Das Projekt "14C content of specific organic compounds in subsoils" wird vom Umweltbundesamt gefördert und von Universität zu Köln, Institut für Geologie und Mineralogie durchgeführt. Organic matter (OM) composition and dynamic in subsoils is thought to be significantly different from those in surface soils. This has been suggested by increasing apparent 14C ages of bulk soil OM with depth suggesting that the amount of fresh, more easily degradable components is declining. Compositional changes have been inferred from declining ä13C values and C/N ratios indicative for stronger OM transformation. Beside these bulk OM data more specific results on OM composition and preservation mechanisms are very limited but modelling studies and results from incubation experiments suggest the presence and mineralization of younger, 'reactive carbon pool in subsoils. Less refractory OM components may be protected against degradation by interaction with soil mineral particles and within aggregates as suggested by the very limited number of more specific OM analysis e.g., identification of organic compound in soil fractions. The objective of this project is to characterize the composition, transformation, stabilization and bioavailability of OM in subsurface horizons on the molecular level: 1) major sources and compositional changes with depth will be identified by analysis of different lipid compound classes in surface and subsoil horizons, 2) the origin and stabilization of 'reactive OM will be revealed by lipid distributions and 14C values of soil fractions and of selected plant-specific lipids, and 3) organic substrates metabolized by microbial communities in subsoils are identified by distributional and 14C analysis of microbial membrane lipids. Besides detailed analyses of three soil profiles at the subsoil observatory site (Grinderwald), information on regional variability will be gained from analyses of soil profiles at sites with different parent material.
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.
Das Projekt "Organic matter composition in the subsoil: Contribution of root litter and microbial-derived compounds" wird vom Umweltbundesamt gefördert und von Technische Universität München, Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt, Lehrstuhl für Bodenkunde durchgeführt. The aim of P2 within the Research Unit 'The Forgotten Part of Carbon Cycling: Organic Matter Storage and Turnover in Subsoils (SUBSOM)' is to contribute to the understanding of the different sources and stabilization processes of subsoil organic matter. This will be achieved by the analysis of the soil organic matter composition in topsoil versus subsoil by 13C NMR spectroscopy in bulk soils as well as organo-mineral associations. This will be done on a number of soil profiles differing in parent material and mineralogy and therefore also in the relevance of organo-mineral associations for subsoil C stabilization. In addition, a specific sampling approach will allow to differentiate three zones associated with the dominating effect of (1) leaching of DOC (the 'bulk soil' between trees), (2) root litter decomposition (the 'root-affected zone'), and (3) direct rhizodeposition of root exudates (the 'rhizosphere' sensu strictu). The contribution of above-ground versus below-ground litter is differentiated by the analysis of cutin and suberin biomarkers. Organic matter derived from microbial sources will be identified by the microbial signature of polysaccharides in the subsoil through the analysis of neutral sugars and amino sugars. Organo-mineral associations will be further characterized by N2-BET analyses to delineate the coverage of the mineral phase with organic matter. With these analyses and our specific analytical expertise at the submicron scale (nanoSIMS) we will participate in selected joint experiments of the research unit.
Das Projekt "Development and risk assessment of transgenic environmentally-friendly insect pest control methods for fruit flies and mosquitoes" wird vom Umweltbundesamt gefördert und von Universität Gießen, Institut für Phytopathologie und Angewandte Zoologie, Abteilung Angewandte Entomologie durchgeführt. Various species of pest insects cause substantial damage to agriculture every year, or transmit deadly diseases to animals and humans. A successful strategy to control pest insect populations is based on the Sterile Insect Technique (SIT), which uses the release of mass-reared, radiation sterilized male insects to cause infertile matings and thus reduce the pest population level. However, irradiation is not applicable to every insect species. Thus, new strategies based on genetic modifications of pest insects have been developed or are currently under investigation.The goal of the proposed research is to improve the development and ecological safety of genetically engineered (GE) insects created for enhanced biological control programs, including the SIT and new strategies based on conditional lethality. A major concern for GE insect release programs is transgene stability, and maintenance of their consistent expression. Transgene loss or intra-genomic movement could result in loss of strain attributes, and may ultimately lead to interspecies movement resulting in ecological risks. To address potential transgene instability, a new transposon vector that allows post-integration immobilization will be tested in the Mediterranean, Mexican and Oriental fruit fly tephritid pest species. In addition, the system will be established in the mosquito species Aedes and Anopheles - carriers of dengue and malaria.Random genomic insertion is also problematic for GE strain development due to genomic position effects that suppress transgene expression, and insertional mutations that negatively affect host fitness and viability. Diminished transgene expression could result in the unintended survival of conditional lethal individuals, or the inability to identify them. To target transgene vectors to defined genomic insertion sites having minimal negative effects on gene expression and host fitness, a recombinase-mediated cassette exchange (RMCE) strategy will be developed that. RMCE will also allow for stabilization of the target site, will be tested in tephritid and mosquito species, and will aid to the development of stabilized target-site strains for conditional lethal biocontrol. This will include a molecular and organismal evaluation of an RNAi-based lethality approach. Lethality based on an RNAi mechanism in the proposed insects would increase the species specificity and having multiple targets for lethality versus one target in existing systems. By seeking to improve transgene expressivity and stabilization of transposon-based vector systems, this proposal specifically addresses issues related to new GE insects by reducing their unintended spread after field release, and by limiting the possibilities for transgene introgression.
Das Projekt "Biological soil crust algae in the polar regions - biodiversity, genetic diversity and ecosystem resilience under global change scenarios" wird vom Umweltbundesamt gefördert und von Universität Köln, Biozentrum, Botanisches Institut durchgeführt. Terrestrial green algae and cyanobacteria are typical and abundant components of biological soil crusts in the Polar Regions. These communities form water-stable aggregates that have important ecological roles in primary production, nitrogen fixation, nutrient cycling, water retention and stabilization of soils. Although available data on green algae and cyanobacteria are generally very limited for the Arctic and Antarctica, their functional importance as ecosystem developers in nutrient poor environments is regarded as high. Therefore, the main goal of the interdisciplinary project is, for the first time, a precise evaluation of their 1.) Biodiversity as well as of 2.) The infra-specific genetic diversity, 3.) ecophysiological performance and 4.) transcriptomics of the most abundant taxa in biological soil crusts isolated from the Antarctic Peninsula and Arctic Svalbard. Biodiversity will be investigated using a classical culture approach in combination with molecular-taxonomical methods as well as with metagenomics. The infra-specific genetic diversity of the most abundant green algae and cyanobacteria will be studied using fingerprinting techniques, and a range of selected populations characterized in relation to their physiological plasticity. Temperature and water availability, two key environmental factors for terrestrial organisms, are currently changing in Polar Regions due to global warming, and hence their effect on growth and photosynthesis response patterns will be comparatively investigated. The data will indicate whether and how global change influence population structure and ecological performance of key organisms in polar soil crusts, and help to make predictions on the future significance of the ecological functions of these pioneer communities. Such a multiphasic approach has never been applied before to soil algae and cyanobacteria in both Polar Regions, and hence represents one of the key innovations of this proposal.
Das Projekt "Origin and fate of dissolved organic matter in the subsoil" wird vom Umweltbundesamt gefördert und von Leibniz Universität Hannover, Institut für Bodenkunde durchgeführt. Dissolved organic matter (DOM) is one major source of subsoil organic matter (OM). P5 aims at quantifying the impact of DOM input, transport, and transformation to the OC storage in the subsoil environment. The central hypotheses of this proposal are that in matric soil the increasing 14C age of organic carbon (OC) with soil depth is due to a cascade effect, thus, leading to old OC in young subsoil, whereas within preferential flowpaths sorptive stabilization is weak, and young and bioa-vailable DOM is translocated to the subsoil at high quantities. These hypotheses will be tested by a combination of DOC flux measurements with the comparative analysis of the composition and the turnover of DOM and mineral-associated OM. The work programme utilizes a DOM monitoring at the Grinderwald subsoil observatory, supplemented by defined experiments under field and labora-tory conditions, and laboratory DOM leaching experiments on soils of regional variability. A central aspect of the experiments is the link of a 13C-leaf litter labelling experiment to the 14C age of DOM and OM. With that P5 contributes to the grand goal of the research unit and addresses the general hypotheses that subsoil OM largely consists of displaced and old OM from overlying horizons, the sorption capacity of DOM and the pool size of mineral-associated OM are controlled by interaction with minerals, and that preferential flowpaths represent 'hot spots' of high substrate availability.
Das Projekt "Linking soil architecture formation with changing permafrost regime to carbon turnover in high latitude soils at multiple spatial scales" wird vom Umweltbundesamt gefördert und von Leibniz Universität Hannover, Institut für Bodenkunde durchgeführt. Most soils develop distinct soil architecture during pedogenesis and soil organic carbon (SOC) is sequestered within a hierarchical system of mineral-organic associations and aggregates. Permafrost soils store large amounts of carbon due to their permanently frozen subsoil and a lack of oxygen in the active layer, but they lack complex soil structure. With permafrost thaw more oxidative conditions and increasing soil temperature presumably enhance the build-up of more complex units of soil architecture and may counterbalance, at least partly, SOC mineralization. We aim to explore the development of mineral-organic associations and aggregates under different permafrost impact with respect to SOC stabilization. This information will be linked to environmental control factors relevant for SOC turnover at the pedon and stand scale to bridge processes occurring at the aggregate scale to larger spatial dimensions. We will combine in situ spectroscopic techniques with fractionation approaches and identify mechanisms relevant for SOC turnover at different scales by multivariate statistics and variogram analyses. From this we expect a deeper knowledge about soil architecture formation in the transition of permafrost soils to terrestrial soils and a scale-spanning mechanistic understanding of SOC cycling in permafrost regions.
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 "Where to stop? - Efficient projections of correlated impacts at different levels of global warming (EXPACT)" wird vom Umweltbundesamt gefördert und von Potsdam-Institut für Klimafolgenforschung e.V. durchgeführt. The political dialogue on climate stabilization targets demands robust calculations of climate change impacts at different levels of global mean temperature (GMT). The new research group will meet this demand by developing an efficient, probabilistic Emulator of climate eXtremes and their imPACTs (EXPACT), providing unprecedented, spatially correlated projections of the repercussions of different GMT changes. Focusing on the agricultural sector, the potential for simultaneous crop yield losses, and the risk of non-linear responses propagating throughout the world economic system will be quantified. The design of the emulator will in particular allow accounting for different adaptation strategies.
Das Projekt "Herstellung und in-situ-Funktionalisierung von Polymerpartikeln in der flüssigen Phase" wird vom Umweltbundesamt gefördert und von Universität Erlangen-Nürnberg, Lehrstuhl für Kunststofftechnik, Sonderforschungsbereich 814 - Additive Fertigung durchgeführt. Dieses Projekt verfolgt das Ziel neue, optimierte Partikelsysteme für die additive Fertigung in der Flüssigphase zu erzeugen. Für die Herstellung der Ausgangsstoffe werden zwei alternative Prozessrouten untersucht. Über die Nassmahlung sowie die Schmelzemulgierung mit jeweils integrierter Oberflächenfunktionalisierung werden Partikelsysteme zwischen etwa 2 und 50 Mykrometer mit optimalen Fließ- und Packungseigenschaften hergestellt und damit die Voraussetzungen geschaffen, die verarbeitbaren Partikelgrößen in der additiven Fertigung deutlich abzusenken. Im ersten Projektteil werden Polymermaterialien unterhalb ihrer Glastemperatur in einer Rührwerkskugelmühle zerkleinert. Die Verwendung von Alkoholen erlaubt ein Kaltmahlen im Temperaturbereich bis herunter zu minus 80 Grad C. Beim Schmelzemulgierverfahren wird der Polymerausgangsstoff in einem flüssigen Medium, in dem er schlecht löslich ist, geschmolzen. Die Schmelze wird infolge hoher Scher- und Dehnbeanspruchung unter Zusatz entsprechender Hilfsstoffe zur Tropfenstabilisierung emulgiert. Nach Abkühlung der Emulsion, Erstarren des Polymers und Abtrennung der flüssigen Phase stehen pulverförmige Ausgangswerkstoffe zur Verfügung. Besonderer Vorteil der Schmelzemulgierung ist es, dass sphärische Partikeln hergestellt werden können. Die erzeugten Partikelgrößenverteilungen hängen in beiden Herstellungsverfahren von der Beanspruchungsintensität und von der Verweilzeitverteilung des Produktes ab. In beiden Fällen geht es darum optimal auf die additive Fertigung hin zugeschnittene Partikelgrößenverteilungen zu erzeugen. Erfolgt die Stabilisierung und Oberflächenfunktionalisierung über Nanopartikel, die an der Oberfläche der festen oder flüssigen Polymerpartikel angelagert werden, können zusätzlich die Haftkräfte durch Steuerung der Oberflächenrauheit maßgeblich reduziert werden und damit optimale Fließeigenschaften eingestellt werden. Beide Prozesse werden im Hinblick auf die nötige massespezifische Zerkleinerungsenergie, um die bestimmte Produktpartikelgrößenverteilung zu erhalten, optimiert.
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