Das Projekt "Sub project: Spherule layers in the 2011 ICDP drilling in the Barberton Mountain Land: Early impact record on Earth" wird vom Umweltbundesamt gefördert und von Museum für Naturkunde - Leibniz-Institut für Evolutions- und Biodiversitätsforschung durchgeführt. The 2011 ICDP drilling 'Barberton Mountain Land' drilled relatively unweathered rare late Archean volcanic and sedimentary rocks including the oldest known impact ejecta layers on Earth. The chemical signature (high Iridium concentrations, Chromium isotopic ratios) of some of these up to tens of cm thick Archean spherule layers advocate that these ejecta deposits formed dominantly from extraterrestrial material. The ejecta layers contain millimeter sized spherules that are larger and form thicker layers compared to any impact ejecta layer known from Phanerozoic sediments, including the global ejecta layer of the Chicxulub impact catering event that terminated the Mesozoic era of Earths history. We propose to conduct 1) bulk chemical analyses of major and trace elements, 2) petrographic, micro-chemical and mineralogical characterization of the impact ejecta layers, and 3) LA-ICP-MS elemental mapping of platinum group element (PGE) distributions. This aims at 1) characterization of the ejecta layers, 2) identification of the phases hosting the extraterrestrial PGE signature, 3) discrimination of the primary geological evidence of the impact event from those characteristics that resulted from syn- and post-sedimentary alteration. We want to exploit the geological evidence for extracting key information regarding size, type and frequency of projectiles impacting the Archean Earth.
Das Projekt "Submarine Groundwater-Fluxes and Transport-Processes from Methane Rich Coastal Sedimentary Environments (Sub-GATE) - Task 8: Groundwater flow modelling" wird vom Umweltbundesamt gefördert und von Universität Stuttgart, Institut für Wasserbau durchgeführt. The goal of the project is to establish a 2D and a 3D groundwater flow model at the transition of subterranean-submarine hydrological regime of proposed seepage systems. To achieve this the enhancement of the numerical formulation and solution procedure of the sharp interface modeling approach for multilayered aquifer systems is necessary. These enhancements include an improved choice of the dependent variables to yield a more robust conservative numerical approximation, less restrictive vertical leakage calculation, rigorous treatment of well conditions, full Newton-Raphson treatment of nonlinearities, and the use of an efficient solver technique (UG, see BASTIAN, 1993). The approach is based on the multiphase flow, transport and energy model (MUFTE, see HELMIG et al., 1994). The necessary steps are: 1. Simulating the submarine groundwater discharge at the outflow of a vent and a seep area by a two dimensional flow and transport model (MUFTE UG). Different characteristic hydrological and submarine flow regimes of the examined area will be studied with the purpose to predict the order of magnitude of water and (non-reactive) mass fluxes at the vent and seep sites. By adjusting the model in order to approximate the representative hydraulic and chemical parameters, the main mechanisms which are controlling the submarine groundwater discharge will be analyzed. 2. Based on these studies of the subterranean-submarine flow regime a numerical model will be established and calibrated for the prediction of the water and mass fluxes in different subdomaines of the area of interest.
Das Projekt "Challenges in luminescence dating applications of quartz" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Bayreuther Zentrum für Ökologie und Umweltforschung (BayCEER), Lehrstuhl Geomorphologie durchgeführt. Luminescence dating methods using quartz may suffer from i) incomplete optical resetting (bleaching) of the latent signal at deposition, ii) limited saturation dose and,thus, limited time range using UV-A or blue emissions. The project objectives first consists in exploring and separating OSL emissions from quartz of different sensitivity to light and to isolate components suited for specific dating applications with the Linear Modulation technique. Rapid environmental change with or without human impact will be dated more precisely and more reliably using this sophisticated technique. Secondly it is tried to extend the upper dating limit by using orange-red TL emissions (RTL) from quartz extracted from heated samples (e.g., crustal xenoliths from volcanic eruptions) and from sediments which are too old for conventional OSL dating. Both approaches require fundamental research into the luminescence characteristics of (dose-saturated) quartz crystals from different geological origin (granitic, hydrothermal, sedimentary). Objectives in order: 1. Sampling and refining pure quartz from different geological and petrographic environments and from a well-studied last glacial loess section (Nussloch). 2. Investigating basic luminescence characteristics from different quartz of different origin, with focus on OSL components (LM-OSL) and red TL emissions (RTL). 3. Testing improved techniques (LM-OSL) to recognize incomplete or inhomogeneous signal resetting at deposition and to precisely determine the true burial dose. 4. Extending the upper limit of luminescence dating through use of RTL emissions from heated and from sedimentary quartz. 5. Improving and ensuring of dose rate calculations using different low-level methods including modeling of disequilibrium and spatial non-homogeneity if applicable. 6. Comparing dating results from loess with independent chronologies and other high resolution records of rapid climate change.
Das Projekt "Abundance, activity and interreation of phototrophic and chemotrophic microbial iron oxidation in freshwater sediments" wird vom Umweltbundesamt gefördert und von Universität Tübingen, Zentrum für Angewandte Geowissenschaften (ZAG), Arbeitsgruppe Geomikrobiologie durchgeführt. In freshwater sediments, iron oxidation is dominated by phototrophic and chemotrophic (aerobic and nitrate-reducing) Fe(ll)-oxidizing microorganisms. Although these biogeochemical processes have been investigated in detail in laboratory studies, not much is known about their spatial distribution, interactions (e.g. competition) amongst each other, as well as their response towards environmental perturbations (i.e. temperature, geochemical variations (nutrient, organic matter input)). This research proposal aims to investigate the activity, abundance and resource competition between different chemotrophic (aerobic and (autotrophic/mixotrophic) anaerobic nitrate-reducing) and phototrophic ironoxidizing microorganisms. In order to better understand the spatial distribution of nitrate-reducing iron oxidizing bacteria, microbial nitrate-producing and competing, nitrate-depletion processes will also be studied throughout the sedimentary redox gradient. In addition, the activity and abundance of the ironoxidizing processes will be quantified with (geo)microbiological, molecular and novel spectral imaging techniques. Using high resolution geochemical measurements (microsensors) we will characterize the environmental conditions these bacteria experience in order to determine the role of spatial and functional niche competition in microbial iron oxidation and the interconnection to the N-cycle. Iron mineral formation will be investigated as a function of the microbial spatial and temporal activity, depending on environmental perturbations. The proposed research study will strongly improve the understanding of iron cycling, the interconnection to the N-cycle, as well as interactions and competition between phototrophic and chemotrophic metabolisms in aquatic environments.
Das Projekt "Modeling Geomagnetic Excursions" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum durchgeführt. Periods of extreme geomagnetic change such as geomagnetic excursions have frequently occurred throughout geological time. Characterizing their behaviour is essential for a full understanding of the geodynamo and the interaction of Earths magnetic field and the space environment. We propose to model the global behaviour of Earths magnetic field between 10 and 50 ka using palaeomagnetic data. During this time the geomagnetic field showed significant variability in direction and intensity, including two well documented excursions: Laschamp and Mono Lake. No model currently exists that spans the total length of this time period, yet this period could provide great insights into the geodynamo. The ultimate goal of the project is to synthesize the results from our empirical modelling with those from numerical dynamo simulations, so that a deeper physical understanding of geodynamo processes can be gained. We will compile all sedimentary and volcanic palaeomagnetic data coupled with geochronological data spanning this period. This data will be added to a community available database along with all rock magnetic and sedimentological metadata. This will allow a detailed assessment of the data used in the modelling. Low quality palaeomagnetic data and erroneous age models may distort geomagnetic field structures generated by our new model and it is a key objective of this study to assess the fidelity of the palaeomagnetic and chronological data included in the modeling. Using this data we will construct a temporally continuous global spherical harmonic geomagnetic field model through a regularized least squares inversion of the data using spherical harmonics in space and cubic B splines in time. This model will enable assessment of the geomagnetic at the core-mantle boundary, the Earths surface and at elevated altitudes. Our key scientific objective is to determine where excursions fit into the spectrum of geomagnetic field variations and how the geodynamo processes that generate excursions differ from those that produce secular variation and reversals.
Das Projekt "Arid Southern Levant: a joint environmental and human history for the Holocene, derived from new archives of climate change (Dead Sea edge, Jordan)" wird vom Umweltbundesamt gefördert und von Universität Bern, Departement Biologie, Institut für Pflanzenwissenschaften durchgeführt. This project proposes to explore the potential of sedimentary sequences from arid Southern Levant to record past environmental and climate changes that can be compared with the evolution of human societies during the Holocene. The Levant, crucible of history, actually possesses very few archives of past climate change in its most arid parts, which restricts the possibility to compare, on a regional scale, environmental variation and the evolution of human communities through time. The region is characterised by contrasted bioclimatic conditions, from Mediterranean-type to arid. Most of the known records of environmental change are located in the moister, Mediterranean zones of the region, where increased water availability permits the presence - or the better preservation - of high-resolution and continuous archives of past climates. However, the potential of the arid environments of the Southern Levant (roughly corresponding to modern Israel, Palestine, and Jordan) to harbour records of Holocene (last ca. 11,500 years) climate change, is far from being exploited to its full extend. Following the unique discovery of Holocene organic, peat-like deposits in the rain-shadow of the Dead Sea area in Jordan, this project proposes to investigate the potential of this currently arid region to record past environmental and climate change. The organic sequences present in the mountain slopes East of the Dead Sea have been shown to contain very good pollen information. Results from a preliminary pollen study provided in particular evidence for the periodic extension of Mediterranean-type forest vegetation, from the upper Mediterranean plateaus down to the study area. These organic sequences can be further exploited to generate more precisely dated (mainly through radiocarbon techniques) and higher-resolution records of climate and environmental change for the Holocene. Pollen data will be complemented by a series of other proxies: charcoal studies indicating recurrent fires, spores and fungi revealing past grazing activities, diatom assemblages showing changes in the water quality, increased detrital content marking periods of enhanced erosion. All these results can then be integrated into dynamic models of local environmental changes and vegetation response. Furthermore, the same area contains multiple sequences of spring carbonates (tufa / travertine) waiting to be studied. The stable isotopic (oxygen and carbon) composition of spring carbonates can provide a good record of past climate change, as it registers variations in environmental factors such as temperature, parent-water composition (itself related to the source and amount of rainfall), and evaporation. The presence of carbonate sequences near organic sequences on the edge of the Dead Sea, offers an unprecedented occasion to directly compare the isotopic variations of carbonate series with environmental variations recorded in the peaty archives.
Das Projekt "The Swiss contribution to the ICDP Lake Van Drilling Project: Linking modern seismic and biogeochemical signatures to 500,000 years of environmental history" wird vom Umweltbundesamt gefördert und von Eidgenössische Anstalt für Wasserversorgung, Abwasserreinigung und Gewässerschutz, Abteilung Wasserressourcen und Trinkwasser durchgeführt. This SNF proposal seeks funding for the continuation of the Swiss contribution to the Lake Van Drilling Project executed by the International Continental Scientific Drilling Program (ICDP). Among other previous Swiss ICDP engagements, the Lake Van Drilling project was pivotal in triggering the newly established SNF-supported Swiss membership in ICDP. Further, the SNF Swiss contribution is a central building block of the entire ICDP PaleoVan initiative. Lake Van is the fourth-largest terminal lake in the world, extending 130 km WSW-ENE 1674 m above sea level on a high plateau in eastern Anatolia, Turkey. The lake is surrounded by active volcanoes within a tectonically active area and it is known to accumulate fluids emanating from the Earths mantle. The partly annually-laminated sedimentary record down to 220 m depth recovered from Lake Van during the ICDP PaleoVan drilling operations in 2010 has been shown to be an excellent palaeoclimate and palaeoenvironment archive. The continuous, high-resolution continental sequence, which covers several glacial-interglacial cycles (greater than 500 kyr), represents a unique possibility to investigate in detail the climatic, environmental, and volcanic changes that occurred in the Near East, the cradle of human civilization, during much of the Quaternary Period. Furthermore, the sediments contain an invaluable record of past earthquake activities, allowing the construction of a catalogue of prehistoric earthquakes and making it possible to study fluid transport in the continental crust that was triggered by seismic events. In this context, the societal vulnerability of the area to seismic hazards was dramatically documented by the occurrence of the devastating earthquake of magnitude 7.2 close to the city of Van on 23 October 2011 (hereafter referred to as the VE11 earthquake). This unfortunate and tragic event offers a unique opportunity to calibrate the past seismic events recorded in the sediments of Lake Van and the related emission of fluids from the solid earth to a modern seismic analogue. Sediment and fluid transport triggered by this major seismic event need to be quantified in order to calibrate the sedimentological record, which is targeted by the follow-up field campaign proposed within this project extension. The continuation of the Swiss initiative, embedded in the overarching ICDP drilling project on Lake Van, encompasses all the 5 initial research modules (A-E) of the ongoing SNF project (200021-124981). Within this proposal extension, the extended modules (A*-E*) will focus on key issues and new developments that expand the initial topics, with a special emphasis on the recent major earthquake VE11 and its biogeochemical and sedimentological implications. At the same time, this extension will also allow the results that have already been acquired to be further analysed and written up for publication by the project team. A large number of publications is foreseen. (...)
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 "Fire, climate change and human impact in tropical ecosystems: paleoecological insights from the East African region" wird vom Umweltbundesamt gefördert und von Universität Bern, Departement Biologie, Institut für Pflanzenwissenschaften durchgeführt. Fire is an important ecological factor of disturbance in African tropical ecosystems, driving vegetation dynamics and regulating nutrient cycling and biomass. The significance of wildfires for future environmental processes is underlined by recent projections of global warming, which predict more frequent and more intense extremes of natural events. Particularly in East Africa, where population growth and natural resource exploitation are among the highest in the world, strategies for sustainable economic development will have to deal with environmental changes at regional to continental scales. Understanding such complex responses to global change requires long-term records, since only they provide a way to observe the response of ecosystems to large-magnitude environmental change on decadal and longer time scales. We use high-resolution charcoal data from lake-sediment cores to reconstruct past fire/climate/human interactions in East Africa, aiming in particular 1) to understand how the fire regime influenced vegetation dynamics during the last millennia in savannah-type and sub-humid tropical ecosystems, 2) to test whether changes in fire regime are coupled with episodes of past climatic extremes inferred from the available sedimentological data, and 3) to detect early human deforestation and the timing of increased fire frequencies beyond its natural variability. Additionally, we will apply novel techniques such as molecular markers (benzene polycarboxylic acids, BPCAs) to complement the standard sedimentary approaches to reconstruct Holocene fire history. The proposed research addresses new, highly relevant questions for today's key issue of sustainability (economic development, natural resource management, adaptation of vulnerable communities to global change). Additionally, it will contribute with new high-quality data to ongoing multi-proxy research concerning the magnitude, frequency, and rates of past climate change in equatorial East Africa. Finally, the project will contribute to our understanding of tropical ecosystem functioning and its interaction with regional, cultural, and economic systems.
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