Das Projekt ÖkoKauf der Stadt Wien hat es sich zum Ziel gesetzt, durch die Erstellung von ökologischen Kriterien, Pilotprojekte und durch Bewusstseinsarbeit das Beschaffungswesen im Magistrat Wien weiter zu ökologisieren. In diesem Rahmen widmete sich der Arbeitskreis 'Desinfektionsmittel unter der Leitung der Wiener Umweltanwaltschaft (WUA) der Aufgabe, für Hygienefachleute ein Instrument zur Beurteilung der Auswirkungen von Desinfektionsmitteln auf Gesundheit und Umwelt zu erstellen. Das Österreichische Ökologie-Institut führte eine Daten- und Literaturrecherche durch, das Umweltbundesamt nahm ergän-zende ökotoxikologische Tests an Wirkstoffen und -produkten vor und 'die umweltberatung ermittelte stationsbezogene Desinfektionsmittelverbräuche in Wiener Krankenanstalten. Die Recherche- und Testergebnisse zu Desinfektionsmittelwirkstoffen und -produkten wurden in einer vom IFZ konzipierten und von der Magistratsabteilung 14 realisierten Datenbank zusammengefasst. Um die ökotoxikologischen Produkteigenschaften vergleichbar zu machen, wurde vom IFZ ein Bewertungsraster entwickelt und in die Datenbank integriert. Dabei werden nachteilige Wirkungen auf die Gesundheit anhand von vier Wirkungskategorien erfasst: Akute Giftigkeit; Reizwirkung auf die Haut; Sensibilisierung, allergenes Potenzial sowie Erbgutschädigende, krebserzeugende und fruchtschädigende Eigenschaften. Zusammen mit der Berücksichtigung des Verhaltens in Oberflächengewässern (Abbauverhalten, Bioakkumulationspotenzial, Toxizität für Wasserorganismen) sowie dem Verhalten in Kläranlagen werden insgesamt sechs Bewertungszahlen generiert, die auf einer Skala von 1 (vernachlässigbar) bis 5 (sehr hoch) das gesamte Gefährdungsprofil des Stoffes beschreiben sollen. Das Gefährdungsprofil eines Handelsproduktes errechnet sich aus den Gefährdungsprofilen der darin enthaltenen Wirkstoffe anhand eines Algorithmus: Dabei wird die Annahme getroffen, dass die Produkteigenschaften von der Konzentration der darin enthaltenen Wirkstoffe abhängen. Bei der Bewertung ist außerdem zu gewährleisten, dass ein Wirkstoff mit einem hohen Gefährdungspotenzial angemessen berücksichtigt wird, auch und gerade wenn seine Konzentration im Produkt gering ist. In der Literatur wird dazu eine logarithmische Skalierung vorgeschlagen. Die Bewertung berücksichtigt derzeit die Wirkstoffe sowie Anwendungsverdünnungen. Die Zusammenfassung der Produkte in Verwendungs- bzw. Expositionskategorien ermöglicht letztlich eine vergleichende Bewertung. Da das Bewertungsraster gerade auf eine vergleichende Bewertung von Produkten abzielt, unterliegt er einer ständigen kritischen Diskussion, die auch häufig von den Herstellern geführt wird. Dieser Umstand sowie das Faktum von Produktlebenszyklen erfordern ein ständiges Update der in der Datenbank enthaltenen Informationen und eine Anpassung des Bewertungsmodells an den aktuellen Stand von Forschung sowie Standards der Stoff- und Produktpolitik.
If one considers the high elevation treeline as a global phenomenon, many local drivers, which dominated the debate in the past, become less significant, they become modulators of a more fundamental, common cause. Our working hypothesis is that the major driver of treeline formation is the ability to form new structures, rather than the provision of raw materials for these structures. In other words, we suggest that the treeline is a sink (growth) rather then a source (photosynthesis) driven phenomenon, with temperature representing the single most important determinant. We do not question the influence of other factors, but we consider them to represent a suite of regional peculiarities, which may affect the actual position by not more then 100 m in elevation. A detailed discussion of the treeline issue can be found in: Our activities go in several directions. They include treering studies across the treeline ecotone (see ref. below), microclimate measurements at various latitudes and an assessment of the carbohydrate supply status at the tree limit. The worldwide treeline temperature assessment nears its end by 2001, when year-round data from ca. 30 different treeline sites around the globe will be available. As a standard procedure we measure root-zone temperature at 10 cm depth in the shade of tree crowns at the treeline using Tidbit (Onset Corp.) data loggers. Currently available data from 90 % of the stations average at seasonal mean ground temperatures of ca 6.5 C, with very little site to site variation, irrespective of latitude (minimum of 5.5 C on Mexican volcanos at 4000 m and maximum at some maritime temperate zone treelines of ca 7.5 C). The seasonal mean proved to be a better predictor of treeline position than warmest month temperatures or a suite of thermal sums tested. There are regions with no suitable treeline taxa where natural treelines occure at lower elevations (higher temperatures; e.g. Hawaii). In a work on carbohydrate pools we compare treelines in Mexico, the central Alps and in N-Sweden (Abisko). We see no decline of reserves as one approaches the existential limit of trees, in fact, carbohydrate and lipid stores reach a maximum at tree limit. Thus, it seems unlikely that carbon limitation is a cause of treeline formation.
Populations of P. fortinii from allover Europe are examined using microsatellites to construct gene genealogies and infer evolutionary history. The tree-root endophyte Phialocephala fortinii s.l. (mitosporic Ascomycota) is the dominant colonizer of conifer root systems in forests in the northern hemisphere. P. fortinii s.l. is genetically highly diverse and forms a complex of several cryptic species. Recombination occurs or has occurred within cryptic species and to some extent also among them (introgression). Cryptic species occur sympatrically and they can form large thalli, but it remains unclear whether the observed patterns of spatial distribution reflect local climax situations or are the results of recent gene and genotype flow. One of the key objectives will be to estimate population genetic parameters (eg. migration rates, genotype flow, recombination) within and among populations of cryptic species in forests where man-mediated genotype flow can be excluded. Other key objectives are the determination of the number, frequency, distribution and evolutionary history of the cryptic species in Europe and to identify the driving forces for speciation. The approach will be multidisciplinary and will include standard mycological and microbiological methods as well as molecular genetic techniques such as microsatellite fingerprinting and DNA sequencing. The evolutionary history of haplotypes at both the population and species level will be reconstructed and the results will be compared with known patterns of pleistocenic glaciations and postglacial recolonization of host trees. The project will be a significant contribution to the understanding of the population and evolutionary genetics of a versatile and ecologically extremely successful fungal genus and it will shed light on the effects of pleistocenic and postglacial climatic changes on fungal speciation.
Root competition for water and nutrient among species is an ubiquitous feature of terrestrial plant communities influencing abundance and distribution of plants and the dynamics of their communities. The relationship between biodiversity and ecosystem functioning has emerged as a central issue in ecological and environmental sciences. It is commonly believed that increasing species richness increases the stability of communities. Higher plant species diversity might lead to increased exploitation of spatially heterogeneous resources by spatial niche complementarity. Tree species mixtures are generally believed to enhance ecosystem functioning in forests by niche partitioning and complementary resource exploitation due to differences in tree height, crown form, root depth and/ or phenology. In the past, however, most studies focused on the aboveground interaction and coexistence of the tree species, while factors controlling belowground species interactions remain less clear. There is experimental evidence to suggest that below-ground competition in herbaceous communities is size-symmetric in homogeneous soil. However, recent studies in tree communities indicate that fine-root competition may be asymmetric. The main purpose of this project is to characterize the underground niche separation and competition in relation to tree species diversity in mixtures comprising spruce, beech, oak and Douglas fir. Structural traits and spatial distribution of fine roots were investigated using a soil core method and fine-root growth is being assessed using the ingrowth core technique at a site in Kaltenborn, which is part of the long-term biodiversity-ecosystem functioning experiment with tree species of temperate forests (BIOTREE). The objectives of this study were to test the following hypotheses: (1) overall level of soil exploitation increases with the tree species diversity; (2) competitive ability belowground is size-symmetric, and (3) the below-ground competitive ability is species specific. As part of this investigation, we will explore the potential of using Near-infrared reflectance spectroscopy to identify the species identity of fine roots of the different tree species and to quantify the contribution of different fine roots in mixed root samples.
Biodiversity indicators and monitoring frameworks are currently developed at global and European levels. A key tool for monitoring progress in achieving the EU target to halt the loss of biodiversity by 2010 is the recently endorsed set of EU headline biodiversity indicators. A requirement by the EU is to complement the indicator set and the development of biodiversity monitoring frameworks with tools that are able to assess the impacts from Community policies on biodiversity. This BioScore proposal aims at satisfying this requirement by developing a tool for linking pressures from policy sectors to the (change of) state of biodiversity as measured by the presence and abundance of individual species. A database is proposed that will contain information on the ecological preferences of individual species, in relation to individual sectoral pressures and relating to selected Community policies as well as the EU headline biodiversity indicators. This tool will be applied for assessing impacts and the effectiveness of biodiversity conservation policies based on historic data as well as for forecasting future impacts based on existing scenario studies. The results of these assessments will consist of European maps. The BioScore tool will be integrated into existing biodiversity monitoring frameworks and incentives for uptake will be formulated. Also the database will be made freely accessible on the Internet. The specific objectives of this proposal are to: - build a cost-effective impact assessment tool in the form of a European species database with sensitivity scores;apply the tool for the purpose of assessing the impacts of key drivers and pressures on biodiversity; - apply the tool for analysing the efeffectiveness of European policy responses; - apply the tool for modelling European-wide scenarios for selected drivers; - integrate the database into a common monitoring framework to assess the impact of selected pressures on biodiversity.
Der Sauerstoffgehalt kann auch in oberirdischen Pflanzenteilen, besonders in Baumstämmen, auf sehr niedrige Werte absinken. Es scheint, daß ein beträchtlicher Anteil des Sauerstoffs im lebenden Splintholz bei vielen Bäumen mit dem Transpirationsstrom und nicht über Diffusion durch das ziemlich undurchlässige Kambium zugeführt wird. Über die Kurzzeitdynamik der Schwankungen von Sauerstoffgehalten im Holz ist beinahe nichts bekannt. Ein Hauptgrund für die relativ geringe Aufmerksamkeit, die man bisher dem Sauerstoff im Stamm entgegengebracht hat, ist der, daß er mit den traditionellen Methoden schwierig und mühsam zu messen ist. Eine Sauerstoffelektrode auf Basis des Fluoreszenzquenchings erlaubt Punktmessungen von O2-Konzentrationen über längere Zeit und in kleinen Volumina. Sie verspricht, ein höchst wertvolles Werkzeug für ein besseres Verständnis der Sauerstoffverhältnisse in der Pflanze zu werden. Der erste Teil unserer Arbeiten soll einen Überblick über diurnale und jahreszeitliche Schwankungen im Stamm verschiedener Arten erbringen. Wir gehen von der Hypothese aus, daß die Sauerstoffverläufe eine Beziehung zur Anatomie des Baumes und zu seinen Standortsansprüchen, besonders zu seiner Überschwemmungstoleranz, haben werden. Wir stellen hier ferner die Hypothese auf, daß Sauerstoff ein bedeutender Streßfaktor bei Bäumen und besonders wichtig in den Beziehungen zwischen Bäumen und Pathogenen ist. Holzbesiedelnde Pilze könnten die Sauerstoffkonzentration verringern, und zwar entweder durch Atmung oder durch zusätzliche Verstopfung von Gefäßen und Tracheiden, wodurch der Transport mit dem Transpirationsstrom verhindert wird. Wenn Sauerstoff mit dem Transpirationsstrom zugeführt wird, können verschiedene Formen von Streß zur Abnahme der Sauerstoffkonzentrationen im Holz und sogar zu Anoxie führen: Überschwemmung, die den Sauerstoff im Boden verdrängt, starke Trockenheit, die den Saftfluß reduziert, und Infektionen, die die Atmung steigern und den Saftfluß reduzieren können. Anoxie führt oft zur Bildung von Ethanol, einem wichtigen Lockstoff für Borkenkäfer. Hier soll die Hypothese getestet werden, daß verschiedene Arten von Streß den Sauerstoffgehalt herabsetzen, wodurch Ethanol entsteht und Borkenkäfer anlockt. Jedoch werden Transpiration, Stammatmung und die Löslichkeit von Sauerstoff in Wasser auch ohne Streß stark von Klimafaktoren beeinflußt, was Voraussagen in diesem komplexen und ungenügend erforschten System erschwert.
Mobilization of aluminium in acidic soils is regarded as a health threat to many European forests. In this project, we are developing biomarkers indicating Al exposure and effects by capitalizing on genome resources recently established for forest trees. Background: Aluminium (Al) is a highly abundant metal which is innocuous at neutral and weakly acidic soil conditions. As soils become more acidic as a result of natural processes or acid deposition, Al is dissolved into toxic Al cations. This form of Al can inhibit root growth at micromolar concentrations resulting in a reduced and damaged root system. Due to continuing deposition of acidifying compounds, soil acidification and its associated dissolution of Al are regarded as a health threat to many European forests. Because soil acidification not only leads to Al mobilization but also to the depletion of base cations (BC), the molar ratio of BC:Al is widely used as an indicator of soil acidification and potential Al toxicity. However, the utility of this indicator is increasingly questioned, and there is a widespread agreement that biomarkers are needed which reflect physiological changes following Al exposure. Aims: This project aims at the development of biomarkers indicating Al exposure and effects by capitalizing on genome resources recently established for forest trees. The project is carried out within the frame of the COST Action E38 Woody Root Processes'. Methods: As a model tree species, we are using poplar for which the entire genome has been deciphered. Biomarkers will be established based on Al-responsive genes. Such genes will be identified by application of microarrays to poplar treated with Al under controlled conditions. Isolated Al-responsive genes will be used to design easy-to-use biomarkers. The established biomarkers will be validated in greenhouse experiments with poplar cultivated on acidic soils with high concentrations of Al in the soil solution. The project is part of the dissertation of Nadine Grisel.
Exchange processes with the atmosphere lead to the formation and decay of crusts and surface deposits. Surface hoar crystals are hexagonal plate-type crystals which form by deposition of water vapour onto the snow surface. These surface layers are important to accurately simulate snow cover evolution, particularly in the context of weak layer formation and stability evaluation. They are of interest to avalanche researchers, due to their lack of inter crystalline bonding once buried and weak attachment to the original snow surface. A better knowledge of the formation processes and the corresponding meteorological conditions will also increase our understanding of snow - atmosphere interactions, which are important in many other applications such as hydrology or climatology. Whereas some attempts have been made to unveil the subtle micro-meteorological processes involved in surface hoar formation, no study so far concentrated on this processes by measuring sensible and latent heat fluxes with high time resolution and in the alpine environment. Even less well understood than surface hoar formation is the formation of thin breakable crusts at the snow surface. These crusts are often assigned to wind action but very little is known about the formation processes. In this study we propose to address the formation of these surface features focusing on the correlation between observation and measurements of the turbulent fluxes involved, particularly the latent heat flux and the water vapour flux. Therefore sonic anemometers and Li-cors were installed close to the measurement site. The results of the observed surface hoar formation and the other snow parameters will also be compared to the modeled surface hoar formation by SNOWPACK.
The project focuses on R&D concerning ash related problems in biomass combustion and co-firing of biomass in coal fired plants. The main objectives of the project will be to investigate the release of ash forming compounds from biomass fuels in fixed-bed and pulverised fuel combustion systems, to determine presently not available thermodynamic data concerning the melting behaviour of Na, Zn and Pb-rich ashes, to further develop simulation tools for aerosol and deposit formation and to develop and test a new technology (an aerosol condenser) for efficient and cost effective aerosol precipitation in small-scale biomass combustion units. The project will also investigate the influence of particulate emissions from biomass combustion and co-firing plants on the regional air quality and parameters influencing health effects caused by these emissions. Comprehensive laboratory, pilot-scale and large-scale test runs at biomass combustion and co-firing plants as well as modelling of relevant mechanisms for aerosol and deposit formation will form the basis of the work performed and will complement each other. By reaching the aims of the project deposit formation in biomass combustion and co-combustion shall be significantly reduced by optimisation of furnace and boiler designs as well as control systems and by a better choice of fuel blends used. Concerning small-scale biomass combustion, aerosol emissions will significantly be reduced by the application of the new precipitation technology. New data concerning the influence of particulate emissions from biomass combustion and co-firing on health risks will be evaluated and form the basis for a recommendation of emission limits. The project results will contribute to a higher energy efficiency and availability of biomass combustion and co-firing plants and to a significant reduction of aerosol emissions from small-scale biomass combustion plants, promoting the increased use of biomass for energy production in Europe.
Ecophysiological traits (carbon, water and nutrient relations) allowing for the coexistence of different functional types (life-forms) of indigenous trees in Munessa Forest, Ethiopia is proposed. Above and below ground resource acquisition and utilization by Croton macrostachys (facultative deciduous), Podocarpus falcatus (evergreen gymnosperm) and Prunus africana (broad-leafed evergreen) will be investigated as influenced by site conditions and season. In addition to tree growth and canopy characteristics, photosynthesis, respiration and transpiration at different zones of tree crowns will be recorded. Whole-tree transpiration will be followed using the Granier stem-flux system. Partitioning of soil water among the trees will be assessed using 18O/16/O-signatures of xylem sap and of soil water collected from different depths. Seasonal water use of juvenile and adult trees will be compared and the seasonal patterns of fine root biomass production shall be analyzed. Data on nutrient relations, mycorrhizal networks and silvicultural characteristics of the trees, produced by the other collaborating groups will be integrated to explain the coexistence of the three functional types of trees. It is expected that species-specific requirements and strategies of survival and growth of the investigated tree species can be used for an ecologically sound reforestation program of a mixed forest.
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