Das Projekt "Paläoklima Schwarzes Meer" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum durchgeführt. Als weitestgehend abgeschlossenes Randmeer zeigt das Schwarze Meer eine deutliche Empfindlichkeit auf Umweltveränderungen und kann globale und regionale Klimaveränderungen in besonderem Maße verstärken. Trotz dieses hohen Potentials für Paläoklimarekonstruktionen wurden die Sedimente des Schwarzen Meeres bislang nur im geringen Maße zu paläoklimatischen Fragestellungen herangezogen. Die Einzigartigkeit des Schwarzen Meeres besteht darin, dass es während des Spätquartärs einen wiederholten Wechsel von Süßwasser- und marinen Phasen durchlebt hat, die eng mit der Entwicklung des globalen Meeresspiegels verknüpft sind und dem Rhythmus der Eis- und Warmzeiten folgen. Vor allem die geographische Lage des Schwarzen Meeres mit seinen teilweise laminierten Sedimenten ermöglicht es das Wechselspiel von mediterranem, mitteleuropäischem und stärker kontinentalem asiatischen Klimageschehen näher zu untersuchen.
Das Projekt "Evolution, abundance, diversity and trophodynamics of mixotropic protists in Antarctic waters" wird vom Umweltbundesamt gefördert und von Universität Potsdam, Institut für Biochemie und Biologie, Arbeitsgebiet Ökologie, Ökosystemmodellierung durchgeführt. Mixotrophy is a strategy by which organisms combine autotrophy and heterotrophy, Mixotrophy is widespread in freshwater and marine habitats, but little is known about mixotrophic protists in Antarctic waters. Existing studies suggest that mixotrophy, in particular phagotrophy by phototrophys, is advantageous in extreme environments such as Antarctica. Therefore, it is reasonable to assume that mixotrophs play a vital role in Antarctic, aquatic microbial food webs. Indeed, the first documented instance of phagotrophy for a green alga. Pyramimonas gelidicola (Chlorophyta: Prasinophyceae) was from an Antarctic lake. All Prasionphystes share a similar ultrastructure to P. gelidicola, implying that mixotrophy may be common in this genus but is 'switched off' unless conditions are sufficiently extreme. The proposed research aims to further investigate the incidence of phagotrophy in P. gelidicola, look for evidence of mixotrophy in other green algae, characterise the abundance, diversity and trophodynamics of mixotrophic protists in Antarctic lacustrine and marine ecosystems, and determine which factors cause mixotrophy to be 'switched on'. These aims will be achieved through laboratory and in situ field experiments during the period December 2003 to June 2005.
Das Projekt "Sub project: Dynamics of Mid-latitude/ Mediterranean climate during the last 150 ka: Black Sea /Northern Anatolian Paleoenvironmental Reconstructions (DynNAP)" wird vom Umweltbundesamt gefördert und von Universität Göttingen, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Abteilung für Palynologie und Klimadynamik durchgeführt. As an isolated marginal sea, the Black Sea reacted particularly sensitive to paleoclimatic and paleoenvironmental changes and on both global and regional scales. In spite of its unique potential for high resolution paleoclimate reconstructions, late Quaternary sediment sequences of the Black Sea have only subordinately been studied with respect to paleoclimatic questions. This is somewhat surprising considering the key-geographic location of the Black Sea, where climate is strongly affected by two major climate systems; the North Atlantic/Siberian pressure system in winter and the Indian monsoon in summer. Highly-resolved and precisely dated paleoclimate records are crucial for reconstructing past regional climate variability, which can then be compared to paleoclimate records from the North Atlantic, Europe and the Indian monsoon domain. Several core sites in the Black Sea along the North-Anatolian rim can provide records of vegetation dynamics and changing precipitation regimes in the Anatolian hinterland as well as paleoceanographic/ paleolimnologic data of environmental changes in the marine/limnic Black Sea system itself. Uranium-series dated stalagmites from Sofular Cave located at the Black Sea coast in north-western Turkey will provide, as terrestrial counterpart, long complementary paleorecords of changes in vegetation and precipitation. When combined, such records will allow us to better quantify the far-field effects of North Atlantic climate and Indian monsoon during the Holocene, Eemian and the last two glacial/interglacial transitions (T1 and T2).
Das Projekt "Klassifizierung ausgewählter Mesofauna-Taxozönosen (Collembola, Gamasina) von Feldrainen" wird vom Umweltbundesamt gefördert und von RWTH Aachen University, Institut für Umweltforschung, Lehr- und Forschungsgebiet Ökosystemanalyse (ESA) durchgeführt. Ziel der Forschungsarbeit ist die Klassifizierung von Boden-Biozönosen in ausgewählten Feldrainen. In drei Naturräumen (Lössböden der Jülicher Börde, Muschelkalkböden in Mainfranken und pleistozäne Sande bei Leipzig) werden typische Lebensgemeinschaften von Collembola und Gamasina (Taxozönosen) beschrieben. Der wesentliche Unterschied zu anderen Klassifikations-Ansätzen liegt in der induktiven Vorgehensweise: Biozönosen werden allein aufgrund der Artenzusammensetzung an den Standorten typisiert. Vegetationskundliche Kriterien dienen als entscheidendes Hilfsmittel zur Vorauswahl von Flächen mit ähnlichen Standortbedingungen. Hierbei wird gleichzeitig die aufgenommene Vegetation als ein weiteres Taxon der zu beschreibenden Biozönose angesehen. Die typische Artenzusammensetzung ist das integrierte Ergebnis aller denkbaren ökologischen Vorgänge. Ein Ziel der Arbeit ist somit die prospektive Formulierung von Erwartungswerten für Collembolen und Raubmilben auf der Basis vegetationskundlicher Daten. Es sollte daher möglich sein, dieses Mehrarten-System mit hoher Sensibilität zur Bioindikation von Standortveränderungen einzusetzen. Die Kenntnis der Artenstruktur wiederkehrender Lebensgemeinschaften kann der funktionellen Ökosystemforschung hilfreiche Hinweise bieten.
Das Projekt "Genetic microdiversity and ecology of protists-follow up" wird vom Umweltbundesamt gefördert und von Universite de Neuchatel, Institut de Biologie durchgeführt. The recent developments of molecular biology allowed the discovery of a huge genetic diversity in eukaryotic micro-organisms. But to this date, the true extension of this diversity has not been properly evaluated. In addition, these assumptions are based on DNA sequence data solely, without any reference to the morphology, life history and ecological roles of the organisms from which these sequences derived. The aim of my Ambizione project, and in particular of this follow-up, is to start answering to these questions based on a model group, the euglyphid testate amoebae. These organisms are considered as ubiquitous in marine, freshwater and terrestrial environments, and are considered to be especially abundant and diversified in mosses and forest litters. In this project, and in my further research, it is planned to: 1) Evaluate the global genetic diversity of euglyphids in forest soils and mosses, determine which are the hotspots of their diversity and understand their causes. 2) Starting with three morphologically almost identical (but genetically different) strains of Euglypha rotunda (a species considered as ubiquitous and very tolerant), evaluate their ecological requirements by characterising their growth rates at different temperatures and pH values. Preliminary results indicate differential ecological requirements; this indicates that E. rotunda cannot be considered as a single taxonomic unit but rather a complex of cryptic species. These data have capital implications on the use of euglyphids as bioindicators. 3) Entire deep-branching novel clades of euglyphids have been detected in the environment. It is planned to try to detect those with a combination of In-situ hybridisation and scanning electron microscopy to be able to describe new species and families. 4) Try to calibrate a molecular clock for the tree of Euglyphids based on the current fossil record of these organisms. Initially, this record was very poor, but the increasing number of researchers interested in these organisms led to the discovery of many fossils, mostly preserved in lacustrine sediments, but also amber. Here, we will investigate samples dating back from the Eocene. By addressing all these questions, I hope to contribute to the knowledge of general protist diversity. This knowledge will contribute to a better understanding of the role of unicellular eukaryotes in natural ecosystems, a role that is unfortunately still widely underestimated but that is slowly gaining momentum.
Das Projekt "UWOPE" wird vom Umweltbundesamt gefördert und von Universität Basel, Institut für Prähistorische und Naturwissenschaftliche Archäologie durchgeführt. A new development in the lake-dwelling research is the study of complex occupational pattern systems of single settlements in specific areas and within specific time spans. A special emphasis is placed upon the settlements' size, location, typological characteristics and bibliographic aspects. Settlements are now studied from a life history perspective, from construction to abandonment, with a thorough consideration of the single house function, including sacred and profane components of its inhabitants' lives. The chapter focuses in particular on the Neolithic lacustrine lakeside dwelling of the Circum-Alpine region; how their size, development, duration and rotation are determined by a myriad of factors, such as climate, environment, landscape morphology, socio-economic decisions and cultural traits of the single communities.
Das Projekt "Natural and anthropogenic mineral aerosols from ice and sediment Alpine records: Climatic, stratigraphic, and environmental implications." wird vom Umweltbundesamt gefördert und von Universite de Geneve, Institut F.-A. Forel durchgeführt. The investigation of sediment cores from two of the largest freshwater lakes from Western Europe (lakes Geneva and Lucerne) demonstrated that natural sources of trace elements dominated before the European industrial revolution. The heavy metal pollution (e.g. lead, mercury) highly increased following the industrialization of Switzerland after 1850. The implementation of wastewater treatment plants (WWTPs) in the 1960s significantly decreased the metal pollution at the deepwater sites. By contrast, the Vidy Bay of Lake Geneva where are released the WWTP of the city of Lausanne since 1964 was highly contaminated by heavy metals due to the WWTP emissions. Lead isotopic composition furthermore highlighted the industrial pollution sources over the last 200 years. During the twentieth century, industrial releases multiplied by 10 times heavy metal fluxes to hydrological systems located on both sides of the Alps. The remote and small high altitude lake Meidsee (2661 m a.s.l. in the Southwestern Alps) revealed the strong increase in anthropogenic trace metal deposition during the Greek and Roman Empires (ca 300 BC to AD 400), the Late Middle Ages (ca AD 1400), and the Early Modern Europe (after ca AD 1600). The greatest increases in anthropogenic metal pollution were evidenced after the industrial revolution of ca AD 1850, especially in Lake Lucerne where industrial activities and the steamboat navigation released high amounts of fossil fuel combustion residues and heavy metals. The elemental and isotopic composition of sedimentary organic matter from the high-altitude Lake Meidsee provided additional information about the high-altitude Alpine landscape evolution since the Late Pleistocene/Holocene deglaciation in the Swiss Southwestern Alps; and indicated the predominant deposition of algal-derived organic matter with limited input of terrestrial organic matter before the Holocene Climatic Optimum (between 7.0 and 5.5 years ago). This research also investigated faecal indicator bacteria (Escherichia coli and Enterococcus), multiple antibiotic resistant and antibiotic resistance genes, in sediment profiles from different parts of Lake Geneva (Switzerland) over the last decades. Results showed that the WWTP input constituted the main source of pollution for several contaminants, including heavy metals, antibiotics, and antibiotic-resistant bacteria. The Bay of Vidy of Lake Geneva can therefore be considered as a reservoir of bacteria multiple resistance genes. Hence, the human-induced eutrophication in the 1970s highly enhanced the sediment microbial activity, and therein the spreading of antibiotic resistant bacteria and genes in this aquatic environment used to supply drinking water in a highly populated area.
Das Projekt "Biogeochemical fluxes in South-Alpine Lakes: Linking nitrogen and methane dynamics in lacustrine redox-transition zones using a combined stable isotope and molecular approach" wird vom Umweltbundesamt gefördert und von Universität Basel, Umweltgeowissenschaften durchgeführt. Bioavailable nitrogen (N) from anthropogenic sources is an important driver of lacustrine eutrophication. However, N loading in lakes is partially mitigated by microbially mediated processes that take place in redox transition zones (RTZ) within the water column and in sediments. RTZ are also sites of methane (CH4) and nitrous oxide (N2O) production and consumption. As a result of anthropogenic activities, emissions of these greenhouse gases to the atmosphere have significantly increased over the past decades. Lake Lugano is an excellent model system for an anthropogenically impacted lake that represents a hot-spot of quantitative redox-driven transformations involving the green house gases CH4 and N2O, as well as other N species acting as important macro nutrients. Previous studies have revealed that this lake represents an important sink for fixed N and that the anoxic deep-waters and sediments contain high concentrations of CH4. Through the application of stable isotopic, molecular ecological and geochemical techniques, laboratory cultivation and (radio-) tracer studies, the project will try (i) to understand the metabolic pathway involved in N and CH4 elimination in Lake Lugano, (ii) to assess the metabolic rates, at which the respective elimination processes take place, as well as their variability in time and space, (iii) to constrain the isotope effects associated with specific N and CH4 transformations, and (iv) to provide information about the microorganisms involved in these transformations. Thereby, a particularly focus is put on reactions that have essentially been neglected in lacustrine studies thus far, namely the anarobic oxidation of ammonium (anammox) and the anaerobic oxidation of methane (AOM). The project will provide the first comprehensive characterization of early diagenetic reactions in Lake Lugano. Moreover, it may allow insights into novel modes of autotrophic life in lakes. Finally, quantitative estimates of N and CH4 elimination in both the water column and sedimentary RTZ of Lake Lugano will be a prerequisite for ecosystem-scale N and C budgets. Thus, the project will provide important information that is directly pertinent to the health of Lake Lugano in particular, and eutrophied south alpine lakes in general.
Das Projekt "A GC-MS/GC-IRMS for the molecular-level analyses of organic matter and the isotopic characterization of inorganic and organic compounds in aquatic and terrestrial ecosystems" wird vom Umweltbundesamt gefördert und von Universität Basel, Umweltgeowissenschaften durchgeführt. A GC-MS/GC-IRMS for the molecular-level analyses of organic matter and the isotopic characterization of inorganic and organic compounds in aquatic and terrestrial ecosystems Stable isotopes represent a valuable means to constrain specific biogeochemical processes in natural environments. The main objective of the project is to develop an Environmental Laboratory for Aquatic and Terrestrial Biogeochemistry, which will support research that will make use of molecular-level characterization and (compound-specific) isotope ratio determination methods to assess a wide spectrum of biogeochemical transformations in the natural environment and in the laboratory, and to study sources and the fate of organic compounds in marine, freshwater, and soil systems. One of the major goals of the projects that make use of the new instrumental capacities is to understand the interactions of the bio- with the geo- and atmosphere with respect to the transport of organic materials and the transformation of inorganic and organic compounds by plants and microorganisms, which is of ultimate importance for the reduction of green house gases and the cycling of elements in aquatic and terrestrial ecosystems. A prime objective will be to use stable isotope measurements to constrain specific biogeochemical and metabolic processes, as well as sources, transport and degradation of organic matter in aquatic and terrestrial environments, and, in turn, to use these constraints to obtain improved estimates on global and regional C and N fluxes, in modern environments as well as in the past. Planned research themes include: I) using lipid biomarker approaches to study microbial communities in various marine and freshwater environments, II) characterizing organic matter components in lacustrine sediments as well as in soils, and identifying the mechanisms responsible for the longer-term sequestration and degradation of organic C and the emission of greenhouse gases, III) understanding the metabolic pathways of C and N during the symbiosis between microorganisms and plants, and IV) generating data sets for the isotopic composition of nitrate and other N species in various aquatic systems in order to characterize the controls on isotope fractionation of specific N cycle reactions. The spectrum of investigated ecosystems will range from Swiss soil and groundwater systems and small lakes to hydrothermal vent systems in the deep ocean, and the spatial scale of the planned research extends from enzyme biogeochemistry to ocean-scale circulation.
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