Das Projekt "Modelling the impact of global warming on the trophic state of the upper ocean" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR) durchgeführt. The main aim of the proposed research is a quantitative evaluation of the potential impact of global warming on the trophic balance of the upper ocean. Primary production, as well as autotrophic and heterotrophic respiration are all expected to increase with temperature, and a number of experimental culture studies suggest that the increase with temperature is more pronounced for respiration than for production. This notion has been further confirmed on the ecosystem level in recent short-term mesocosm studies. According to these results, an expected direct effect of global warming is a weakening of the biological carbon pump. In contrast to indirect effects arising from changes in circulation and stratification, such a direct temperature effect has not yet been investigated quantitatively on a global scale. Using an Earth System Model of intermediate complexity, the proposed study will investigate the sensitivity of the model's biological pump to different parameterisations of temperature effects on autotrophic and heterotrophic processes, each calibrated by available experimental data from culture and mesocosm studies. The ability of different parameterisations to closely reproduce regional patterns of biogeochemical tracer distributions will first be evaluated for pre-industrial steady-state solutions. In a second step, the model will be forced with IPCC-type CO2 emission scenarios over the 21st century in order to estimate the impact of direct temperature effects on the marine biota relative to indirect effects via changes in circulation and stratification.
Das Projekt "Fate of 17-ethinylestradiol in the aqueous environment and the associated effects on organisms" wird vom Umweltbundesamt gefördert und von RWTH Aachen University, Institut für Umweltforschung, Biologie V, Lehrstuhl für Umweltbiologie und -chemodynamik durchgeführt. Introduction: In aquatic systems, the bioavailability of a compound is dependent on numerous factors such as partitioning between water, different organisms and solids, biotransformation and food web transfer. This project dealt with the fate of an important environmental xeno-estrogen, 17-ethinylestradiol (EE2), in the aquatic environment. Therefore, the kinetics of EE2 in indicator species representing the different trophic levels of an ecosystem were assessed. As primary producers, green algae (Desmodesmus suspicatus) were selected. The water flea Daphnia magna and larvae of the midge Chironomus riparius were introduced as primary consumers of the water phase and the sediment, respectively. Finally, water as well as dietary uptake of EE2 were investigated in a target species and secondary consumer: zebrafish (Danio rerio). Methodology: In a first series of experiments, uptake of 14C-labelled EE2 (14C-EE2) from the water phase and elimination by the different organisms were investigated over time. In a second test series, both primary consumers were fed 14C-EE2 spiked algae in order to study bioaccumulation. Uptake of 14C-EE2 by chironomid larvae after water and sediment spiking was compared, including sediments of different composition. In a third series of experiments, male fish were short term (48 h) exposed to 14C-EE2 through different routes: by water exposure (WE) and by dietary exposure (DE) via both contaminated daphnids and chironomid larvae. Distribution of 14C-EE2 in the fish was studied by measuring the amount of radioactivity (RA) in the different fish tissues. Additionally, the effect of EE2 on the vitellogenin (Vtg) induction in male fish was compared after WE and DE in a long term (14 d) experiment. The RA in liquid samples was quantified by means of liquid scintillation counting (LSC). Solid samples were subjected to combustion in a biological oxidiser, trapping (14)CO2, measured with LSC. Water and organism extracts were analysed by means of HPLC with a radiodetector, except for algae extracts that were subjected to TLC. Metabolites were identified with GC-MS, high resolution LC-MS and enzymatic hydrolysis followed by HPLC with radiodetection. Metabolites, detected in the water phase, were tested for estrogenic activity by means of YES and ER-CALUX assays. Results: Accumulation and effects: Of the four organisms mentioned above, bioconcentration of 14C-EE2 was highest in the algae. Whereas the growth rate of D. subspicatus was significantly affected at high EE2 concentrations compared to unexposed algae, EE2 had no acute effects on D. magna and C. riparius. Daphnids showed a higher bioaccumulation potential after exposure via spiked algae. For chironomids, water exposure was the predominant uptake route. The presence of sediment lowered the bioavailability of 14C-EE2 to the larvae after both water and sediment spiking. Nevertheless, uptake was higher when the nutritional quality of the sediment was better. Etc.
Das Projekt "Sub project: Temperature chaos and microbial food web dynamics" wird vom Umweltbundesamt gefördert und von Universität Köln, Institut für Zoologie, Biozentrum Köln, Arbeitsgruppe Allgemeine Ökologie durchgeführt. Microbial food webs dominate the functioning of marine and freshwater ecosystems. Conclusions on the impact of climatic changes on aquatic ecosystems have generally been based on studies of constant increases in experimental temperatures. However, since the invention of deterministic chaos in the 60ies of the last century, it is known that organisms are confronted with non-linear dynamics of external temperatures. One important forecast for climate changes is the increase of weather (e.g. temperature) variability especially in the middle of Europe. Thus, we would like to contribute to the studies of the current consortia working in the frame of AQUASHIFT with a model study on the dynamic behaviour of experimental food webs. Organisms are not only faced with external irregularities but also with internal (intrinsic) fluctuations of population dynamic parameters. Here we would like to investigate the interaction between non-linear dynamic behaviours of extrinsic and intrinsic factors. We have developed an exceptional model systems consisting of a microbial two-preyone-predator-systems that allows for a detailed analysis of dynamic behaviour under defined chemostat conditions. We will analyze match/mismatches occurring due to the interference of non-linear dynamics of extrinsic (temperature) and intrinsic (population sizes) parameters on different trophic levels and would like to contribute to create a theoretical basis for the understanding of the impact of global changes on aquatic communities.
Das Projekt "Trophic interactions in the soil of rice-rice and rice-maize cropping systems" wird vom Umweltbundesamt gefördert und von Universität Gießen, Institut für Allgemeine und Spezielle Zoologie, Bereich Tierökologie und Spezielle Biologie durchgeführt. Subproject 3 will investigate the effect of shifting from continuously flooded rice cropping to crop rotation (including non-flooded systems) and diversified crops on the soil fauna communities and associated ecosystem functions. In both flooded and non-flooded systems, functional groups with a major impact on soil functions will be identified and their response to changing management regimes as well as their re-colonization capability after crop rotation will be quantified. Soil functions corresponding to specific functional groups, i.e. biogenic structural damage of the puddle layer, water loss and nutrient leaching, will be determined by correlating soil fauna data with soil service data of SP4, SP5 and SP7 and with data collected within this subproject (SP3). In addition to the field data acquired directly at the IRRI, microcosm experiments covering the broader range of environmental conditions expected under future climate conditions will be set up to determine the compositional and functional robustness of major components of the local soil fauna. Food webs will be modeled based on the soil animal data available to gain a thorough understanding of i) the factors shaping biological communities in rice cropping systems, and ii) C- and N-flow mediated by soil communities in rice fields. Advanced statistical modeling for quantification of species - environment relationships integrating all data subsets will specify the impact of crop diversification in rice agro-ecosystems on soil biota and on the related ecosystem services.
Das Projekt "North Atlantic Climate: Predictability of the climate in the North Atlantic/European sector related to North Atlantic/Arctic sea surface temperature and sea ice variability and change (NACLIM)" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Fakultät für Mathematik, Informatik und Naturwissenschaften, Team 452.1: EU-Projekte durchgeführt. Objective: NACLIM aims at investigating and quantifying the predictability of the climate in the North Atlantic/European sector related to North Atlantic/Arctic sea surface temperature (SST) and sea ice variability and change on seasonal to decadal time scales. SST and sea-ice forcing have a crucial impact on weather and climate in Europe. Rather than running climate forecasts ourselves, we will analyse the multi-model decadal prediction experiments currently performed as part of the fifth Coupled Model Intercomparison Project (CMIP5) and critically assess the quality of predictions of the near-future state of key oceanic and atmospheric quantities relevant to the SST and sea-ice distribution and the related climate. Long-term observations of relevant ocean parameters will be carried out, necessary to assess the forecast skill of the model-based prediction results. We will identify those observations that are key to the quality of the prediction and in turn optimize the present observing system. We will quantify the impact of North Atlantic/European climate change on high trophic levels of the oceanic ecosystem as well as on urban societies.
Das Projekt "FOR 438: Die Bedeutung von Biodiversität für Stoffkreisläufe und trophische Interaktionen: Ein Versuchsansatz in Grasslandgesellschaften - Teilprojekt: Diversität und Funktion von arbuskulären Mykorrhiza- und Bodenpilzen mit oxidativem Potential in Grasländern mit unterschiedlichen Stufen pflanzlicher Diversität" wird vom Umweltbundesamt gefördert und von Universität Leipzig, Institut für Biologie I, Lehrstuhl für Terrestrische Ökologie durchgeführt. Das Jena Experiment hat es sich zum Ziel gesetzt Zusammenhänge zwischen Pflanzendiversität und Ökosystemprozessen zu untersuchen. Unsere Arbeiten beschäftigen sich mit einer der Schlüsselgruppen in unterirdischen Ökosystemprozessen - den Pilzen. Das Wirtsspektrum arbuskulärer Mykorrhizapilze (AMF) wird innerhalb der Monokultur-Plots untersucht. In Polykulturen unterschiedlicher Diversität soll der Zusammenhang zwischen Artenreichtum von Pflanzen und AMF vertiefend studiert werden. Durch ein Experiment mit stabilen Isotopen soll der Beitrag der AMF für die Nährstoffverteilung zwischen einzelnen Pflanzenarten, aber auch zwischen funktionellen Gruppen näher beleuchtet werden. Weiterhin wird untersucht, ob Zusammenhänge zwischen Stickstoffmineralisierung, Anreicherung organischer Substanzen sowie der Diversität und dem Expressionsprofil pilzlicher Laccasegene bestehen.
Das Projekt "Biodiversity in agroecosystems: a multi-trophic approach to metacommunities" wird vom Umweltbundesamt gefördert und von Universität Freiburg, Institut für Biologie II durchgeführt. The goal of the proposal is to explore the structure and functioning of metacommunities in ecological compensation areas at a multi-trophic level. First, we will assess the effect of plant diversity and herbivore and/or predator exclusion on metacommunity functioning in sown wildflower strips. We will document the communities inhabiting these experimental plots, paying attention at interactions between species, and with consideration of larger consumers linking these habitats with the surrounding matrix. Second, we will explore the relationship between various measures of the environment (isolation, habitat size) and descriptors of the metacommunities (diversity, composition, abundances, and productivity of various taxonomic groups, food-web structure, temporal variability, local invasions and extinctions). Third, using a high-quality dataset on quantitative food webs and the present data, we will conduct meta-analyses to test various models of community organisation (neutral models of biodiversity, species-area relationship in trophic levels, regional similarity hypothesis, food-web structure). Fourth, we will develop various models describing food-web structure and metacommunities dynamics. We will synthesize our results to develop a theory of 'meta food-webs'. Fifth, we will apply the gained knowledge to improve current agri-environment schemes. The study of species interactions in spatially structured metacommunities is comprehensive and global. As such, this project has a strong potential to provide fundamental insight into conservation biology. This project is multidisciplinary, putting together practitioners, ecologists and mathematicians, and is expected to yield important results both of fundamental and conservation relevance. We will use various methodologies to reach our goals. For the first part, we will set up an experiment with replicated sown wildflower strips where plant species richness and the abundance of major predators (foxes and birds of prey) and/or of major herbivores (voles and slugs) will be controlled (balanced incomplete block design). The other parts will rely on classical meta-analyses, multivariate statistics, and mathematical modelling. For the latter part, we will develop stochastic models to explore the dynamics of communities.
Das Projekt "Harmful Algal Bloom species in Thin Layers (HABIT)" wird vom Umweltbundesamt gefördert und von University College Galway durchgeführt. The project HABIT researches the development and dispersion of HAB populations in sub-surface micro-layers. It focuses on a genus of phytoplankton that has a serious impact on the economic development of the European coastal zone and which frequently occurs in sub-surface, thin micro-layers. The overall objectives of HABIT are to resolve fundamental patterns in the occurrences of Dinophysis and quantify the processes that are important in governing their distribution. To this end, the project HABIT will i) investigate the maintenance and persistence of high density thin layers through studying interactions between fine scale physical diffusion and net growth and trophic relationships within them; ii) investigate the precise role of small scale structures on the coastal shelf as incubators for accumulations of Dinophysis; and iii) utilise physical models to examine the formation and persistence of gyres on the shelf, to predict their transport, and as a consequence HAB events at the coast. A high-resolution vertical profiler will be utilised in tandem with a moored profiling system currently in use in the US for studying HAB species occurrences. Thin layers of Dinophysis will be identified. Small-scale physical processes (vertical and horizontal diffusion) will be measured, and related to net growth. Results will allow an overview of the balance between dispersion and accumulation in the layers and the time-scale of their persistence. Retention zones and other smallscale structures on the coastal shelf will be investigated as incubators for thin layers of HABs using quality physical models to model and predict the formation, persistence and movement of these structures. In this way, potential incubator sites will be shown to depend on the hydrodynamic regime of the coastal ocean. The origins of HAB events will be identified and essential information given to managers, as the only mitigation action possible for naturally occurring events lies in their prediction. As part of the EU-US Cooperation Agreement (US-NSF) Johns Hopkins University, Baltimore, is participating in the HABIT project.
Das Projekt "Transgenic wheat and non-target impacts on insect herbivores and food webs" wird vom Umweltbundesamt gefördert und von Forschungsanstalt Agroscope Reckenholz-Tänikon ART durchgeführt. Genetically engineered (transgenic) crop varieties are grown on a steadily increasing area, covering an estimated 114 million ha in 2007. More than 42 million ha were planted with insect-resistant cotton and maize varieties that express cry genes derived from the soil bacterium Bacillus thuringiensis (Bt). A major concern with the widespread use of insecticidal transgenic crops is their potential impact on non-target organisms. This includes effects on herbivores that are not affected by the expressed toxins and could develop into secondary pests as well as predators and parasitoids that play an important role in natural pest regulation. To date, studies have primarily addressed direct effects of insecticidal proteins on non-target organisms. Here we address an important novel indirect interaction between insect-resistant transgenic plants and non-target organisms. We study the interactions between the plant's inherent defence mechanisms with the introduced trait and how this affects herbivores and their natural enemies. The studies will include detailed investigations on insect-plant interactions under protected conditions. Complementary field studies in the USA will investigate whether effects observed in the laboratory/glasshouse are of ecological relevance, i.e. also expressed under field conditions. The proposed studies address basic questions on plant-insect interactions. The results obtained within this project will thus be of fundamental scientific interest and of importance for ecological risk assessments related to the use of insect-resistant transgenic crops.
Das Projekt "Biodiversity and trophic interactions in agricultural mosaic landscapes, comparing bees, wasps and their natural enemies" wird vom Umweltbundesamt gefördert und von Universität Göttingen, Department für Nutzpflanzenwissenschaften, Abteilung Agrarökologie durchgeführt. Global biodiversity is declining at an alarming rate and traditional conservation areas are no longer sufficient to slow this decline, so the potential contribution of managed land for conservation is increasingly acknowledged. This includes a broadening of the perspective from the field and farm to the landscape level, considering the often neglected spatial and temporal turnover in anthropogenic mosaic landscapes. Here we will use a highly replicated study design with the experimental exposure of standardized nesting resources to examine the relative importance of habitat type to landscape diversity using trap-nesting bees, wasps and their natural enemies. We will analyze the scale-dependence of partitioned biodiversity and quantify host-parasitoid and prey-predator interactions, as well as make food web statistics with a fully quantified interaction web (following Tylianakis et al. 2007, Nature 445: 2002-5). We will show how the major habitat types in our mosaic landscapes (and different years) contribute to overall species richness, comparing wheat, oilseed rape, grassland, field margin strips, fallows and forest margins, which represent a gradient of anthropogenic disturbance. We will examine how landscape composition influences the relative contribution of the six habitat types to species richness by focusing on a gradient of simple to complex structured landscapes. Further, we expect enemy richness to be related to host/prey mortality, so we will contribute to this highly debated topic. The mosaic structure of agricultural landscapes allow to study little known effects of landscape configuration, including spillover effects across habitats, inhibition of dispersal (by hostile cereal fields) and facilitation (by grassy corridors). Experiments with marked bee and wasp individuals allow to describe foraging behaviour and resource use across habitats.
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