Sediment erosion and transport is critical to the ecological and commercial health of aquatic habitats from watershed to sea. There is now a consensus that microorganisms inhabiting the system mediate the erosive response of natural sediments ('ecosystem engineers') along with physicochemical properties. The biological mechanism is through secretion of a microbial organic glue (EPS: extracellular polymeric substances) that enhances binding forces between sediment grains to impact sediment stability and post-entrainment flocculation. The proposed work will elucidate the functional capability of heterotrophic bacteria, cyanobacteria and eukaryotic microalgae for mediating freshwater sediments to influence sediment erosion and transport. The potential and relevance of natural biofilms to provide this important 'ecosystem service' will be investigated for different niches in a freshwater habitat. Thereby, variations of the EPS 'quality' and 'quantity' to influence cohesion within sediments and flocs will be related to shifts in biofilm composition, sediment characteristics (e.g. organic background) and varying abiotic conditions (e.g. light, hydrodynamic regime) in the water body. Thus, the proposed interdisciplinary work will contribute to a conceptual understanding of microbial sediment engineering that represents an important ecosystem function in freshwater habitats. The research has wide implications for the water framework directive and sediment management strategies.
Changes in agroecosystem management (e.g. landscape diversity, management intensity) affect the natural control of pests. The effects of agricultural change on this ecosystem service, however, are not universal and the mechanisms affecting it remain to be understood. As biological control is effectively the product of networks of interactions between pests and their natural enemies, food web analysis provides a versatile tool to address this gap of knowledge. The proposed project will utilize a molecular food web approach and examine, for the first time, how changes in plant fertilisation and landscape complexity affect quantitative aphid-parasitoid-hyperparasitoid food webs on a species-specific level to unravel how changes in food web interactions affect parasitoid aphid control. Based on the fieldderived data, cage experiments will be conducted to assess how parasitoid diversity and identity affect parasitoid interactions and pest control, complementing the field results. The work proposed here will take research on parasitoid aphid control one step further, as it will provide a clearer understanding of how plant fertilization affects whole aphid-parasitoid food webs in both simple and complex landscapes, allowing for further improvements in natural pest control.
The aim of this project is to develop a methodology to quantify the magnitudes and frequencies of individual surface change processes of a rock glacier over several years. We do this by analyzing three dimensional (3D) surface change based on high-resolution, high-frequency and multisource LiDAR data. The derived information will enable us to develop methods to automatically characterize and disaggregate multiple processes and mechanisms that contribute to surface change signals derived from less frequent monitoring (e.g. yearly). Such methods can enhance our general understanding of the spatial and temporal variability of rock glacier deformation and the interaction of rock glaciers with connected environmental systems.
Deviant behaviour on various levels of the food supply chain may cause food risks. It entails irregular technological procedures which cause (increased probabilities of) adverse outcomes for buyers and consumers. Besides technological hazards and hitherto unknown health threats, moral hazard and malpractice in food businesses represent an additional source of risk which can be termed 'behavioural food risk'. From a regulatory perspective, adverse outcomes associated with deviance represent negative externalities that are caused by the breaking of rules designed to prevent them. From a rational choice perspective, the probability of malpractice increases with the benefits for its authors. It decreases with the probability of detection and resulting losses. It also decreases with bonds to social norms that protect producers from yielding to economic temptations. The design of mechanisms that reduce behavioural risks and prevent malpractice requires an understanding of why food businesses obey or do not obey the rules. This project aims to contribute to a better understanding of malpractice on the restaurant/retail level through comparative case studies and statistical analyses of food inspection and survey data. Accounting for the complexity of economic behaviour, we will not only look at economic incentives but consider all relevant behavioural determinants, including social context factors.
Farm structures are often characterized by regional heterogeneity, agglomeration effects, sub-optimal farm sizes and income disparities. The main objective of this study is to analyze whether this is a result of path dependent structural change, what the determinants of path dependence are, and how it may be overcome. The focus is on the German dairy sector which has been highly regulated and subsidized in the past and faces severe structural deficits. The future of this sector in the process of an ongoing liberalization will be analyzed by applying theoretical concepts of path dependence and path breaking. In these regards, key issues are the actual situation, technological and market trends as well as agricultural policies. The methodology will be based on a participative use of the agent-based model AgriPoliS and participatory laboratory experiments. On the one hand, AgriPoliS will be tested as a tool for stakeholder oriented analysis of mechanisms, trends and policy effects. This part aims to analyze whether and how path dependence of structural change can be overcome on a sector level. In a second part, AgriPoliS will be extended such that human players (farmers, students) can take over the role of agents in the model. This part aims to compare human agents with computer agents in order to overcome single farm path dependence.
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.
Glendonites are pseudomorphs after the mineral ikaite (CaCO3 x 6H2O) and composed of calcite (CaCO3). In the past, they have been used as a paleo-thermometer because the primary mineral ikaite, according to observations and experiments, seems to be formed at temperatures near freezing, high alkalinity and high phosphate concentrations in marine sediments. An enigmatic occurrence of the largest glendonites known world-wide, in the Early Eocene Fur Formation of northwestern Denmark offers the unique possibility to shed more light on the actual mechanism and controlling parameters of ikaite formation. Right in the aftermath of the Paleocene-Eocene thermal maximum, a time known for its global pertubation in the global carbon cycle, the formation of authigenic calcium carbonate concretions start in the Fur Formation. In a specific stratigraphic interval inbetween these concretions, the glendonites can be found. We will investigate if termperature changes or changes in geochemical parameters of the Danish Basin caused the sudden formation of ikaite during a time interval that was based on known paleoclimatic reconstructions (semi tropic) not favorable for ikaite formation.
Almond in California represents an agroecosystem pollinated solely by a single species, the European honey bee, a species that is becoming increasingly difficult and expensive to manage due to substantial, unpredictable mortality. Therefore, sustainable and high output production require a more integrated approach that diversifies sources of pollination. For this purpose, detailed data of our understanding how diversity can stabilize pollination are required. The project will identify alternative wild pollinator species and collect high quality data contributing to our understanding of how diversity (pollen and insects) can bolster honey bee pollination during stable and unstable climatic conditions. The research will be carried out on almond orchards in Northern California known to be either pollinator species rich (up to 30 species) or depauperate (honey bees only). The replicated extremes in pollinator diversity represent a unique opportunity to study the effects of diversity on pollination in real agroecosystems combined with laboratory and glasshouse experiments. The overall goal is to provide basic research that is essential for our general understanding of how insect diversity can affect high-quality pollination under land use and climate change.
Fällt ein Regentropfen auf eine Wasseroberfläche oder platzt dort eine Gasblase, so wird in einem komplizierten strömungsmechanischen Prozess eine Vielzahl kleinster Tröpfchen produziert und in die Luft geschleudert. Diese Tröpfchen können ursprünglich im Wasser vorhandene Mikroplastikpartikel in die Luft übertragen. Da sowohl Regen als auch platzende Gasblasen in natürlichen und technischen Systemen wie Ozeanen, Pfützen oder Kläranlagen extrem häufige Ereignisse sind, liegt hier ein potenziell hochrelevanter Migrationspfad von Mikroplastik aus der Hydro- in die Atmosphäre vor. Dieser Prozess soll im vorliegenden Projekt durch eine Kombination aus Modell-Experimenten und Computersimulationen im Detail untersucht und verstanden werden.
Recent discussions on the path eco-hydromorphic research has followed in the past decades highlight the need for greater ecological input into this field. Traditional approaches have been criticized for being largely correlation-based (Vaughan et al., 2009) ecological black boxes (Leclerc, 2005) and strongly relying on weak, disproven and/or outdated assumptions about the dynamics of stream biota (Lancaster & Downes, 2010). In recognition of this, process-oriented research aiming at elucidating and quantifying causal mechanisms has been proposed as a promising approach, though challenging, to study the relations between flow, morphodynamics and biological populations in running waters. In terms of levels of biological organization, it has been recognized that processes determining the response of aquatic biota to hydromorphological alteration occur mainly at the population level. In this sense, relating demographic rates to flow and morphology seems to offer great potential for progress (Lancaster & Downes, 2010). Thus, tapping into existing ecological knowledge (e.g., key patch approach for habitat networks, Verboom et al. 2001; metapopulation theory, Levins 1970; Hanski & Gaggiotti 2004, landscape-scale estimations of habitat suitability and carrying capacity, Reijnen et al. 1995; Duel et al. 1995 2003; population-level viability estimations; Akçakaya 2001; resource utilization scales, ONeill et al. 1988; habitat-use patterns, Milne et al. 1989) in order to link ecology to hydromorphology at a more fundamental level constitutes an important path towards better science and management.
| Origin | Count |
|---|---|
| Bund | 258 |
| Type | Count |
|---|---|
| Förderprogramm | 258 |
| License | Count |
|---|---|
| offen | 258 |
| Language | Count |
|---|---|
| Deutsch | 50 |
| Englisch | 248 |
| Resource type | Count |
|---|---|
| Keine | 203 |
| Webseite | 55 |
| Topic | Count |
|---|---|
| Boden | 215 |
| Lebewesen und Lebensräume | 236 |
| Luft | 197 |
| Mensch und Umwelt | 258 |
| Wasser | 195 |
| Weitere | 258 |