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 "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 "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 "Biodiversity and Ecosystem Functioning in Subtropical Forests (BEF-China)" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für Biogeochemie durchgeführt. The joint Chinese-German-Swiss research project BEF-China (FOR 891) integrates more than 15 German, Swiss, and Chinese universities and institutes into 13 collaborative subprojects. The project was funded in the first phase from 2008-2011 and is now in the third phase, 2014-2016. In 2009 and 2010, the BEF-China project established a large forest biodiversity-ecosystem functioning (BEF) experiment at the subtropical forest site Xingangshan in Jiangxi Province, China. The BEF-China project is the first BEF forest experiment in the highly species-rich subtropics. The present research concentrates on measuring ecosystem functions in the experimental plots, namely primary productivity, carbon and nitrogen storage, nutrient cycling, and prevention of soil erosion. The latter process is an ecosystem service which has until now never been studied in an experimental biodiversity manipulation, but has prominent importance in this region. An additional research focus will be interactions with other trophic levels and strata (herb layer, soil macrofauna, herbivores, decomposers, mycorrhiza, soil microorganisms). To meet these objectives, a wide range of scientists contribute to the BEF-China project, involving groups focusing on tree growth allometries, plant functional traits, plant-insect interactions, wood decomposition, phosphorus cycling and erosion potential. As in the first phase, the project continues to be carried out in close collaboration between Chinese and European researchers with complementary knowledge and skills. In addition, the measurements in the CSPs are continuing. The joint synthesis of the data gathered in both phases of BEF-China will help to resolve one of the most central issues in ecology and global change biology: how plant diversity may maintain vital services in forest ecosystems.
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 "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.
Das Projekt "Homogenisation of ECosystem functioning between Temperate and Neotropical streams due to AgRicultural land usE (HECTARE)" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Umweltforschung GmbH - UFZ, Department Seenforschung durchgeführt. The expansion and intensification of agricultural areas and the associated deforestation, eutrophication and modification of habitat heterogeneity remain the most important stressors to stream ecosystem functioning worldwide. The alteration of key environmental characteristics may cause the loss of functional attributes specific for streams in different climate zones and may ultimately lead to a homogenisation of stream ecosystem functioning. Previous studies were mostly restricted to a single function in a particular biome and a thorough understanding on the potential for an agriculturally driven functional homogenisation of stream ecosystems among climate zones is lacking. The project HECTARE analyses ecosystem functioning of pristine and agricultural streams situated in the German Harz and in the Brazilian Cerrado and Atlantic forest. By the novel combination of quantification of food webs and measurements of ecosystem productivity and respiration, HECTARE delivers a mechanistic understanding on energy- and matter fluxes in temperate and Neotropical streams including their trophic coupling to the catchments. Building on that, key pathways of whole-ecosystem matter and energy fluxes that are impacted by agricultural land use will be identified. The inter-biome approach proposed with HECTARE will allow for a synthesis of impact patterns associated with agricultural land use and an analysis of the degree of functional homogenisation of stream ecosystems.
Das Projekt "Forschergruppe (FOR) 456 degree of celsius: The role of Biodiversity for element cycling and trophic interactions: An experimental approach in a grassland community" wird vom Umweltbundesamt gefördert und von Universität Jena, Institut für Ökologie durchgeführt. In einem Langzeitexperiment in Jena soll der Zusammenhang zwischen Pflanzendiversität und Ökosystemprozessen untersucht werden. Schwerpunkte der Untersuchungen sind die Elementkreisläufe und die trophischen Beziehungen zwischen verschiedenen Organismengruppen. Sechzig häufige Pflanzenarten mitteleuropäischer Wiesen (Arrhenatherum) wurden ausgesucht, um in 20 m x 20 m großen Versuchsparzellen Artengemeinschaften bestehend aus einer bis 16 Pflanzenarten und einer bis vier funktionellen Gruppen anzusäen. In diesen Artengemeinschaften sollen die Interaktionen zwischen den einzelnen Pflanzenarten und zwischen den verschiedenen trophischen Ebenen (Pflanzen, Invertebraten, Mikroorganismen) untersucht werden. Arbeitsgruppen aus den Bereichen Hydrologie, Biogeochemie, Bodenkunde, Botanik, Zoologie, Agroökologie werden eng zusammenarbeiten, um eine Kohlenstoffbilanz der Ökosysteme aufzustellen und die Umsatzraten und Verluste von Nährstoffen in den Systemen in Abhängigkeit von der Biodiversität zu berechnen. In dem Experiment soll die Frage beantwortet werden, welchen Einfluss Biodiversität auf Ökosystemprozesse wie etwa die Produktivität, Kohlenstoffspeicherung oder Grundwasserqualität hat. Der gewählte experimentelle Ansatz reflektiert die aktuelle Diskussion über die Frage, ob einzelne Arten, funktionelle Typen oder Diversität per se für den Einfluss von Biodiversität auf Ökosystemfunktionen verantwortlich sind. Das geplante Langzeitexperiment hebt sich von bereits durchgeführten Experimenten mit ähnlicher Fragestellung ab durch (1) den Ansatz, eine Reihe von Unterexperimenten auf den gleichen Versuchsparzellen durchzuführen, (2) die ausführliche Untersuchung der Kohlenstoffspeicherung, (3) die Quantifizierung des gesamten Stickstoff- und Phosphorkreislaufs, und (4) die Untersuchung interspezifischer Interaktionen.
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 "Consumer - interaction webs and the effect of aboveground vertebrates and invertebrates on ecosystem processes" wird vom Umweltbundesamt gefördert und von Universität Jena, Institut für Ökologie durchgeführt. The effects of invertebrate herbivory on ecosystem processes will be tested by excluding above-ground invertebrates from 5 m x 5 m subplots of all experimental plots using biocides. Net primary productivity and other ecosystem processes will be quantified in both treated and unmanipulated parts of the plot to study the relationships between plant diversity, invertebrate herbivory and ecosystem functioning. A second objective of this project is to test the interactions between plant diversity, plant productivity and the structure of the invertebrate community. Above-ground invertebrates will be sampled repeatedly from all grassland plots and allocated to a certain trophic role, i.e. herbivore, predator, parasitoid, or detritivore. Statistical modeling will reveal the influence of plant diversity manipulations on invertebrate density and invertebrate diversity at different trophic
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