Organotin and especially butyltin compounds are used for a variety of applications, e.g. as biocides, stabilizers, catalysts and intermediates in chemical syntheses. Tributyltin (TBT) compounds exhibit the greatest toxicity of all organotins and have even been characterized as one of the most toxic groups of xenobiotics ever produced and deliberately introduced into the environment. TBT is not only used as an active biocidal compound in antifouling paints, which are designed to prevent marine and freshwater biota from settlement on ship hulls, harbour and offshore installations, but also as a biocide in wood preservatives, textiles, dispersion paints and agricultural pesticides. Additionally, it occurs as a by-product of mono- (MBT) and dibutyltin (DBT) compounds, which are used as UV stabilizer in many plastics and for other applications. Triphenyltin (TPT) compounds are also used as the active biocide in antifouling paints outside Europe and furthermore as an agricultural fungicide since the early 1960s to combat a range of fungal diseases in various crops, particularly potato blight, leaf spot and powdery mildew on sugar beet, peanuts and celery, other fungi on hop, brown rust on beans, grey moulds on onions, rice blast and coffee leaf rust. Although the use of TBT and TPT was regulated in many countries world-wide from restrictions for certain applications to a total ban, these compounds are still present in the environment. In the early 1970s the impact of TBT on nontarget organisms became apparent. Among the broad variety of malformations caused by TBT in aquatic animals, molluscs have been found to be an extremely sensitive group of invertebrates and no other pathological condition produced by TBT at relative low concentrations rivals that of the imposex phenomenon in prosobranch gastropods speaking in terms of sensitivity. TBT induces imposex in marine prosobranchs at concentrations as low as 0,5 ng TBT-Sn/L. Since 1993, for the littorinid snail Littorina littorea a second virilisation phenomenon, termed intersex, is known. In female specimens affected by intersex the pallial oviduct is transformed of towards a male morphology with a final supplanting of female organs by the corresponding male formations. Imposex and intersex are morphological alterations caused by a chronic exposure to ultra-trace concentrations of TBT. A biological effect monitoring offers the possibility to determine the degree of contamination with organotin compounds in the aquatic environment and especially in coastal waters without using any expensive analytical methods. Furthermore, the biological effect monitoring allows an assessment of the existing TBT pollution on the basis of biological effects. Such results are normally more relevant for the ecosystem than pure analytical data. usw.
In Vivo und in vitro Verabreichung von Nahrungsmittelzusatzstoffen (Tartrazin, Gelborange, Amaranth, Benzoesaeure, Sorbinsaeure, Na-Disulfit, K-Disulfit, Glutamat) und von Nahrungsmitteln (Ei, Milch, Nuesse, Fisch, Rohkost, Fleisch, Mehlsorten) an Patienten mit Verdacht auf entsprechende Unvertraeglichkeiten. Symptome: Kopf- und Bauchschmerzen, Asthma, Rhinitis, Diarrhoe, Urticaria, anaphylaktischer Schock. Mit Hilfe der in vitro Provokationen werden Korrelationen zwischen Mediatorenprofilen und der klinischen Symptomatologie hergestellt. Ziel der Untersuchung: Etablierung eines validen, nicht invarsiven, den Patienten nicht gefaehrdenden diagnostischen Verfahrens zur Objektivierung der nahrungsmittelinduzierten pseudoallergischen Reaktionen.
Salinity reduces the productivity of cucumber (Cucumis sativus L.) through osmotic and ionic effects. For given atmospheric conditions we hypothesize the existence of an optimal canopy structure at which water use efficiency is maximal and salt accumulation per unit of dry matter production is minimal. This canopy structure optimum can be predicted by integrating physiological processes over the canopy using a functional-structural plant model (FSPM). This model needs to represent the influence of osmotic stress on plant morphology and stomatal conductance, the accumulation of toxic ions and their dynamics in the different compartments of the system, and their toxic effects in the leaf. Experiments will be conducted to parameterize an extended cucumber FSPM. In in-silico experiments with the FSPM we attempt to identify which canopy structure could lead to maximum long-term water use efficiency with minimum ionic stress. The results from in-silico experiments will be evaluated by comparing different canopy structures in greenhouses. Finally, the FSPM will be used to investigate to which extent the improvement of individual mechanisms of salt tolerance like reduced sensitivity of stomatal conductance or leaf expansion can contribute to whole-plant salt tolerance.
In the last decades agricultural policy has gained increasingly in complexity. Nowadays it influences the food and agricultural sector from the global market down to the farm level. Widespread research questions, like the impact of the WTO negotiations on the farm structure, most often require comprehensive modeling frameworks. Thus, different types of models are utilized according to their comparative advantages and combined in a strategically useful way to more accurately represent micro and macro aspects of the food and agricultural sector. Consequently, in recent years we have seen an increase in the development and application of model linkages. Given this background, the overall objective of this subproject is a systematic sensitivity analysis of model linkages that gradually involves more and more characteristics of the linkage and the corresponding transfer of results between models. In addition, the project aims to answer the following specific question: How does structural change at the farm level influence aggregate supply and technical progress? Under which conditions is it possible to derive macro-relationships from micro-relationships? How does the aggregation level influence the model results and how can possible problems be overcome? This procedure is used to quantify the effects and to derive conditions for optimal interaction of the connected models. The analysis is based on the general equilibrium model GTAP (Global Trade Analysis Project) and the farm group model FARMIS (Farm Modelling Information System) which are employed in conjunction to analyze the effects of WTO negotiations on the farm level.
Our long term activities aim at a functional understanding of alpine plant life. Overall our research shifted gradually from studying resource acquisition (e.g. photosynthesis) toward resource investment and questions of developement. As with treeline, sink activity seems to be the major determinant of growth. A common misconception associated with alpine plant life finds its expression in the use of the terms 'stress' and 'limitation'. See the critique in: Körner C (1998) Alpine plants: stressed or adapted? In: Press MC, Scholes JD, Barker MG (eds.) Physiological Plant Ecology. Blackwell Science , 297-311. Ongoing experimental work: The influence of photoperiod on growth and development in high elevation taxa (Ph.D. by Franziska Keller in cooperation with the Dept. of Geography, University of Fribourg). We test, whether and which species are responsive to earlier snow melt. It appears there exists a suite of different sensitivities, suggesting biodiversity shifts. We also tested the influence of nutrient addition on high elevation pioneer plants and run a longer term project on the interactive effect on sheep tramplng, nitrogen deposition and warming as part of the Swiss National Project NFP 48. A Europe-wide assessment of ground temperatures in alpine grassland is part of ALPNET (see associated organisations). The assessment provides a basis for comparing biodiversity in alpine biota from 69 to 37 degree of northern latitude. (Nagy et al. (2003) Ecological Studies, Vol. 167. 577 p. Springer, Berlin). A synthesis of research in functional ecology of alpine plants over the past 100 years was published in 1999.
The understanding of long-term, natural climate variability on different spatial and temporal scales is crucial to assess the recent climate change in a global to regional context. Since glaciers are considered as very important climate indicators, the understanding of past and present glacier variations is a key task for evaluating current climate change. Alpine and Scandinavian glaciers do react differently on variations of energy balance, temperature, precipitation and atmospheric circulation. This project investigates the importance of regional/continental temperature and precipitation as driving factors for glacier dynamics (retreats, advances) during the period from the Little Ice Age (LIA) to the early 21st century. Historical information from different archives will allow the reconstructions of glacier length fluctuations and mass balances from (western) Scandinavian glaciers and of a transect from western to the eastern Alps. Further, the sensitivity of Alpine and Scandinavian glaciers to variations of temperature and precipitation, including glacier advances and retreats covering half a millennium, will be studied by means of (non-linear) statistical approaches. A complementary method by reconstruction of mass balances using a continuity approach combined with a GIS-based energy balance model and gridded climate data will also be applied. Finally, the mass balances are extrapolated for the entire Alps and Scandinavia using a distributed energy balance model. This enables a synoptical analysis of European climate related to its significance for glacier fluctuations for the last half millennium. Moreover, the project will shed some light on the future glacier behaviour within the different mountain ranges of Scandinavia and the Alps using existing distributed mass balance and ELA models using different scenarios on the increase of temperature and the change of precipitation. We will also address the question of a changing perception of the glaciers in the Alps and Scandinavia for the last few centuries. The fear of threat by glaciers in early times has changed today to a fear of loss of glaciers as beautiful landscape by the current rapid change of climate. The long-term glacier length record for the Alps and Scandinavia will be stored in the existing database of the Global Terrestrial Network on Glaciers (GTN-G) as part of the World Glacier Monitoring Service (WGMS). A close cooperation between the Universities in Bern/Zurich and Bergen, Norway, will ensure a mutual enrichment of the scientific research. The project is coupled with a joint proposal submitted by the Bjerknes Centre for Climate Research in Bergen. Both projects base on a mutual collaboration of data and knowledge exchange. Finally, to inform the public about the consequences of the current glacier change is crucial, and glaciers are excellent indicators for the public perception of climate change in mountainous areas.
Lakes can be considered as sentinels and thus indicators and integrators of environmental pressures such as climate change. To maintain lakes in a healthy ecological state is nowadays a major task for water management authorities, and will be increasingly so under climate change which is believed to negatively affect lake ecosystem functioning. Phytoplankton plays a key role in lake dynamics as it is at the base of the food web, and changes in its community have potential to affect the entire lake ecosystem. In addition, Cyanobacteria, the only freshwater phytoplankton group that is able to produce cyanotoxins, are capable of inflicting considerable harm to lake ecosystems and to human health through contamination of drinking water supply and toxin accumulation in fishes. Phytoplankton is thus a common indicator to assess the ecological status of lakes. Without understanding the complex mechanisms and processes that underlay a lake ecosystem in a changing climate, planning for future lake management and adaptation will be compromised. Numerical deterministic modelling is today the most appropriate approach to address these global and complex mechanistic features of lake ecosystems. Modeling studies play a key role in exploring the processes responsible for changes since they can be used to test the sensitivity of lakes to both observed and projected changes in climate. The aim of this project is to apply an ecological model to Lake Geneva, which has not been undertaken yet. Lake Geneva, a deep sub-Alpine lake, is the largest lake in central Europe and an essential source of drinking water, having not only a high ecological value, but also economic and social values. Due to its considerable environmental importance, it is crucial to assess, through numerical modeling techniques applied, how the Lakes water quality may be impaired; especially in view of the fact the observed rate of warming since 1900 is more than double that of the observed global average. Moreover, the hydrodynamic characteristics of Lake Geneva, the watershed of its most important inflow river Rhône, as well as the regional climate, have already been modeled. In coupling these models together, we will close the essential gaps, through which we will be able to understand the links between climate, watersheds, and lakes and provide a whole, integrated ecosystem perspective. This integrative model will provide an accurate predictive management tool to help take decisions and response strategies in a timely manner. It is generally recognized that future climate change will have an important impact on Lake Geneva, with a likely deterioration of its water quality. This will be manifested by high phosphorus concentrations, by phytoplankton biomass increase, by a change in phytoplankton composition, by an asynchronous phenology and by an emergence of potentially toxic Cyanobacteria.(...)
Wide applications in Europe show that weed management strategies can be considerably improved when computerized expert systems, decision models and population-dynamic models are applied. If these management systems are transferred and adapted to the specific production systems of the North China Plain, herbicide use can be significantly reduced and the evolution of persistent weed populations in the major arable crops can be avoided. The main objective of this subproject will be to create efficacy-based models analyzing herbicide performance in major crops and to create population-based models for herbicide use analyzing the yield losses caused by weed competition. For these models it is necessary to determine the sensitivity of major weed species to herbicides and to explore the potential of reduced dose rates for herbicide use. Furthermore it is necessary to investigate weed management practices combining preventive (timing of seeding, crop rotation and tillage) and direct methods (chemical and physical methods) of weed control. For population dynamic models it is necessary to determine long-term economic weed threshold estimating the changes in the soil seed bank. Finally both models will be combined in a decision support system for weed control in North China Plain Production Systems. The applicability of this decision support system will be tested in field experiments.
Global climate change in cryogenic regions has dominated the research agenda recently, as investigators seek ways of identifying the hazards to infrastructure in cold regions to establish distinct uncertainties through a risk based consideration of sensitivity and consequences and thereby mitigate the risk of permafrost degradation. The latest IPCC report states that temperature increased at the top of the permafrost layer in the Arctic by up to 3 C since the 1980s. The permafrost base has been thawing at rates of up to 0.04 m/yr, permafrost degradation is causing changes in land surface characteristics and drainage systems and snow cover has decreased in most regions. This has been greatest at lower elevations, e.g. in Switzerland. Melting massive ice or degrading permafrost is becoming increasingly susceptible to causing initiation of slope instabilities and debris flows, having caused the 1997 Val Pola debris flows in the Italian Alps. Recent instabilities in the Vallée du Du Durnand in Valais and the Bérard Rock Glacier in France, both in 2006, emphasise the growing concern. Clear risks were also identified in Turtmanntal, Val d'Anniviers and Mattertal, where some rock glacier features indicated formation of crevasses and depressions at critical positions in the landform and increased risk of failure through the body of the mountain permafrost. Knowledge of the evolving thermal state and internal structure, as well as the response of permafrost soils to a gradual warming cycle, is necessary. This project focuses on the variations of geotechnical response of Alpine permafrost with time and temperature. The time effects are important, since a rock glacier will flow or creep downhill. Landforms have changed in the smaller rock glaciers in the West Alps, where these are particularly sensitive to warming scenarios. Clearly this may lead to instability. The specific goals are: o to investigate artificially frozen soils in the laboratory to understand the relative influences of stresses, soil-ice content, particle size and shape, strain rate and temperature on the strength and stiffness, particularly within the thawing zone, o to obtain equivalent strength and stiffness data from stored (and future) cored samples of Alpine Permafrost and to compare with those from artificial frozen soil, o to establish relationships between key parameters for both artificial and real mountain permafrost, o to test an existing constitutive law to represent the thermo-hydro-mechanical behaviour of Alpine permafrost, o to obtain relevant parameters for future input to the constitutive model and subsequent numerical analysis of the test data.
In den zurückliegenden 1.5 Jahren des Projektes konzentrierten sich die Arbeiten auf das erste bereits fertiggestellte vertikale Seismometer-Array des ICDP-GONAF-Observatoriums auf der Tuzla Halbinsel im Südosten Istanbuls. Aufgrund des verbesserten Signal-Rausch-Verhältnisses an den Bohrlochseismometern im Vergleich zu den Oberflächenstationen war es möglich, deutlich mehr M kleiner als 0 Mikrobeben zu detektieren. Diese Messdaten stellten die Grundlage für die bereits durchgeführten seismologischen Studien dar. In der hier beantragten Verlängerung werden wir unsere Erdbebendatenbank für das östliche Marmarameer fortlaufend erweitern, indem wir die im Sommer 2014 fertig gestellten Seismometer-Arrays auf der Armutlu-Halbinsel in die Detektionsalgorithmen integrieren, sowie dann auch weitere vier GONAF-Bohrlocharrays, deren Fertigstellung bis Frühjahr 2015 geplant ist. Es wurden verschiedene Methoden zur Bestimmung oberflächennaher Eigenschaften des Tuzla-Standortes, wie z.B. seismische Geschwindigkeiten und Dämpfung, angewendet und angepasst. Dieselben Methoden werden auf die neuen GONAF-Stationen übertragen, um zu verifizieren, ob die Beobachtungen in Tuzla standortspezifisch, oder auch für andere geologische Formationen repräsentativ sind. Die dann erstmals durchgeführte vergleichende Analyse unterschiedlicher Standorte in der Region wird neue Einblicke geben, um die Auswerteverfahren für die Korrektur von Standort-Effekten weiterzuentwickeln. Dies ist z.B. für eine genaue Abschätzung von Erdbeben-Quellparametern essentiell. Darüber hinaus planen wir, Processing-Methoden des Vertical-Seismic Profiling einzusetzen, um die Zweige der Nordanatolischen Verwerfungszone unterhalb des östlichen Marmarameeres abzubilden (passive fault-zone imaging). Dabei wird die lokale Seismizität genutzt, die in kleiner als 20 km Epizentralentfernung von den GONAF-Stationen in Tiefen von 5 bis 20 km auftritt und an den verschiedenen Tiefenstockwerken der GONAF-Arrays registriert wird. Schließlich werden Wellenformen-Registrierungen von erstmals in 300m Tiefe eingesetzten 3-Komponenten 1Hz MARK Seismometern ausgewertet, unter Anderem um verstärkt S-Wellen-Eigenschaften der Region zu untersuchen.
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