Das Projekt "Binnenseesedimente als indirekte Archive fuer die Rekonstruktion der Umweltdynamik in Raum und Zeit: Eichung und quantitative Rekonstruktion in den Alpen (AQUAREAL)" wird vom Umweltbundesamt gefördert und von Universität Bern, Systematisch-Geobotanisches Institut durchgeführt. In a first phase (1993-1995) the basic scientific tools are built up and developed that will enable statistically reliable quantification of palaeo proxy-data in terms of past environment. This involves the development of modern transfer-functions and the calibration of proxy-data time-series. The project uses two independent approaches: a) establishment of mathematical/statistical relationships between different biological organisms and environmental variables, i.e. calibration or transfer functions by means of modern surface sediment samples. Surface samples from 68 lakes in altitudes between 300 and 2400 m a.s.l. have been sampled and the analyses of the different microfossils groups is in progress. b) cross-correlation of sub-recent varve parameters in Baldeggersee with instrumental meteorological records for the period of 1901-1993. Little is known about the relationship between ecological and climatic parameters influencing varve formation in lakes. It is therefore essential to define potentially sensitive climatic parameters in the varves as well as to separate statistically the nutrient impact of the lake from the climate signal. Measurements of sediment accumulation during the summer portion of the annual layer may provide a direct or indirect measure of climatic events that affect the biological growing season. The proposed project aims at reconstructing the past dynamics of terrestrial and aquatic ecosystems. In a first phase (1993-1995) the basic scientific tools will be built up and developed that will enable statistically reliable quantification of palaeo proxy-data in terms of past environment. This quantitative environmental reconstruction involves the development of modern transfer-functions and the calibration of proxy-data time-series. The proposed project has two independent parts: a) calibration or transfer functions for climate (pollen, Chironomids) and/or nutrients (Cladocera, diatoms) by means of 50-100 modern surface sediment samples. b) cross-correlation of sub-recent varve parameters in Swiss Plateau lakes with instrumental meteorological records and tree-ring time-series. In a second phase (1996-2000) the results of these two approaches will be applied to long proxy-data records along a transect across the Alps in order to reconstruct past environments and to assess natural variability, as well as to identify phases and amplitudes of the driving parameters (e.g. climate, human impact). Leading Questions: What are the natural variability and long-term dynamics of ecosystems and climate? What are the amplitudes of past rates of change? How long are the response times of ecosystems to perturbations? How are environmental signals reflected in lacustrine sediments?
Das Projekt "LAMODATE: Lakustrische Ablagerungen als Monitoren von Dynamik im Grenzbereich Atmosphaere-Erdoberflaeche - 1. Projektphase: Kalibration chemisch-physikalischer Tracer, Testgebietstudien" wird vom Umweltbundesamt gefördert und von Eidgenössische Technische Hochschule Zürich, Geologisches Institut durchgeführt. Leading Questions: Variations in the stable-isotope composition of Alpine and peri-Alpine surface waters are expected to ultimately reflect the different origins of the air masses (Atlantic vs. Mediterranean) - with superimposed factors such as seasonality- and altitude effects. Questions: - Is it possible, through calibration of the recent isotope patterns (and their extensions into the past via lacustrine proxy data) to reconstruct past changes in atmospheric circulation? - Is it possible through the calibration of annual varve deposits (thickness and grain-size parameters) to quantify local drainage characteristics (precipitation and ice-melt) and to follow them back beyond measured meteorological and hydrological records? Abstract: The project consists of two parts: I. Mittelland-lake sediments: their geochemical signal of climate change Oxygen isotope signatures in lake sediments provide information on past rainfall and atmospheric circulation pattern. Oxygen isotope curves from Baldeggersee and from Greifensee record distinct changes in precipitation since the end of the Little Ice Age. II. Alpine-lake sediments: their clastic response to climate change Sediments from the Engadine lakes store the Holocene erosion history of an alpine valley and the clastic sediment record documents the impact of glacial erosional activity on the alpine landscape evolution. Low sedimentation rates offer the opportunity to trace the erosional history throughout the Holocene. Complementary information: Water cycle processes leave characteristic signals in lacustrine sediments. However, more detailed information on the present natural variability is needed to obtain quantitative interpretations of climatic variations in the past. The scope of this project is to calibrate proxy-data in the present and to apply them to the interpretation of past climate changes. In the first phase of this project we will sample surface waters (rivers and lakes) and measure oxygen- and hydrogen isotopic compositions in order to obtain an insight into integration processes and patterns for the different climatic regions of Switzerland. We will also collect short sediment cores from selected lakes in order link modern proxy data to their environmental controls and to follow the most recent evolutionary trends. This calibration should then enable the objective interpretation of stable-isotope records preserved in sedimented lacustrine carbonates in terms of past climatic conditions. Clastic varves from lakes in the Engadine test-region will be used to determine variations of catchment runoff rates caused by changes in precipitation and/or temperature.
Das Projekt "Zufluss-Untersuchungen des Sempacher- und Baldeggersees" wird vom Umweltbundesamt gefördert und von Kanton Luzern, Amt für Gewässerschutz durchgeführt. Phosphorzufuhr in Seen, Abwassereinleiterkataster, Abwassersanierungen in laendlichem Raum, Abflussmengen-Messungen, Verminderung der Phosphorfrachten, Seen-Eutrophierung und Landwirtschaft.
Das Projekt "Seensanierungen: Sempachersee und Baldeggersee" wird vom Umweltbundesamt gefördert und von Kanton Luzern, Amt für Umweltschutz durchgeführt. Die Reaktion der luzernischen Mittellandseen auf see-interne (Sauerstoffeintrag ins Tiefenwasser und Zwangsdurchmischung) und externe Massnahmen wird mit Hilfe physikalischer, chemischer und biologischer Messungen verfolgt. Die Seenueberwachung erfolgt durch die EAWAG. Die Ueberwachung des Einzugsgebietes (Zufluesse, Abwasserreinigungsanlagen, Landwirtschaft) wird vom kantonalen Umweltschutzamt koordiniert. Als Leitsubstanz wird das Phosphor untersucht.