Das Projekt "Sub project: Influence of fluids from the ocean crust on growth and activity of deep-biosphere populations (IODP Leg 301)" wird vom Umweltbundesamt gefördert und von Carl von Ossietzky Universität Oldenburg, Institut für Chemie und Biologie des Meeres durchgeführt. The sediment column of IODP Site 1301 of the eastern flank of the Juan de Fuca Ridge (water depth: 2650 m, sediment coverage: 265 m) is characterised by a diffusive flow of hydrothermal fluids from the underlying ocean crust, a steep temperature gradient of 0.23 degree C/m and two sulfate-methane transition zones. One goal of our project is to understand the role of fluids as a driving force for the marine deep biosphere by introducing electron acceptors to deeply buried sediments. This hypothesis was supported by cell quantification and activity measurements along the sediment column. Elevated cell numbers at the sediment-basement interface gave the first evidence for a microbial community stimulated by crustal fluids. Potential phosphatase activity was enhanced in phosphate-depleted layers towards the sediment-basement interface. Rates of sulfate reduction and anaerobic oxidation of methane were elevated within the lower sulfate-methane transition zone. Further investigations are focussed on isolation and characterisation of indigenous microorganisms. Molecular screening, used to determine the microbial composition of enrichment cultures from all sediment layers, revealed different phylotypes. However, as we are dealing with slowly growing prokaryotes, they need up to six months to form a colony. Therefore, the isolation and characterisation of new isolates and the preparation of publications will be finished until the end of the application period.
Das Projekt "Teilprojekt: Hoch-Präzisions Pb (double spike) und Sr-Nd-Hf-Isotopenvariation der oberen Ozeankruste des Leg 206 (Site 1256, östlicher Zentralpazifik)" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), Forschungsbereich 4 Dynamik des Ozeanbodens, Forschungseinheit Magmatische und Hydrothermale Systeme durchgeführt. About 50 percent of the present-day ocean crust and thus -30 percent of the Earth's surface was formed at mid-ocean ridges at fast to superfast spreading rates ( greater than 80 mm/y full rate). IODP Site 1256 in the Cocos Plate (Eastern Central Pacific) represents the most complete in situ section of ocean crust formed at a superfast spreading center drilled thus far. Scientific participants of IODP Expeditions 309 and 312 are currently investigating the recovered material from the deeper, mainly intrusive, part of the hole (below 750 mbsf). Relatively few geochemical data, however, exist thus far for the upper part (drilled during OOP Leg 206) consisting of -250 m of marine sediments and -500 m of lava flows. The upper 750 m represent -50 percent of the total depth drilled at Site 1256. In the course of an ongoing project, our group is investigating the Sr, Nd, Hf and Pb (with the double spike method, DS) isotopic variation in the Exp. 309/312 material, including the low- to high-temperature lava-dike alteration and the dike-gabbro transition zones. Here we propose to examine the down-hole geochemical variation of Leg 206 sediments and lavas, in order to generate a complete and detailed record of the Sr-Nd-Hf-Pb (DS) isotopic and relevant trace element variations of the entire oceanic crust drilled at Site 1256. These data will provide important new insights into 1) magma genesis at superfast spreading ridges (East Pacific Rise); 2) the effects and timing of subsequent alteration including element fluxes in oceanic crust formed at superfast spreading rates (compared to slower rates); 3) the chemical evolution of seawater; 4) element cycles in subduction zones, and 5) the contribution of ocean crust to mantle plume sources. The proposed project is an important extension of our current studies and complements well the research activities within the international Site 1256 IODP scientific community.
Das Projekt "Sub project: Spatial and temporal seismic imaging of fluid migration through the crust in the W-Bohemia/Vogtland earthquake swarm area" wird vom Umweltbundesamt gefördert und von Universität Leipzig, Institut für Geophysik und Geologie, Abteilung Geophysik durchgeführt. The W-Bohemia/Vogtland region is characterized by spatially clustered swarm earthquake activity with a typical source depth of 6-12 km. Degassing of upper mantle derived fluids, correlating with seismicity, is observed as well as temporal variations in the amount and composition of the emitted gas, isotope composition, and in earthquake source processes. Evidence for fluid-controlled earthquake triggering was found from earthquake source studies and inter-event relationships. Fluid reservoirs have been proposed for the upper crust as well as for the crust-mantle transition zone, but their direct observation is still missing. Epicentres and gas springs are spatially separated and the pathways of fluids to the surface remain unresolved as are their relations to the crustal seismic structure. These features make the Eger Rift/Vogtland area a prime site for scientific drilling. In this project spatial and temporal imaging of crustal seismic structures and fluid dynamics will be achieved by various approaches. We will test the hypothetical existence of a fluid reservoir and estimate its spatial extent using seismic velocity and attenuation tomography as well as coda studies. We will measure the temporal evolution of stress and fluid dynamics giving information about changes in the upper crust during a swarm earthquake cycle. The 3D and 4D seismological models delivered by this project will constrain the decision for an optimal ICDP drilling location in the Eger Rift system.
Das Projekt "Sub project: El'gygytgyn impact structure, Siberia: Investigation of a mid-size impact structure in volcanic target" wird vom Umweltbundesamt gefördert und von Museum für Naturkunde - Leibniz-Institut für Evolutions- und Biodiversitätsforschung durchgeführt. The young (3.6 Ma), 18 km diameter El'gygytgyn crater in Chukotka, NE Russia, is one of the best-preserved impact structures on Earth. The complex crater structure was formed in a silicious volcanic target, which makes it a rare terrestrial equivalent to the abundant impact structures in volcanics on other planetary surfaces (e.g., on Mars). After the impact a crater lake formed - within which undisturbed and continued lacrustrine sedimentation took place to establish a continuous, long-term reservoir of paleoenvironmental information. The crater was never covered by glaciers or ice shields, which allowed the development of a unique arctic climate archive. In spring 2009 a drilling campaign by the 'International Continental Drilling Project (ICDP)' recovered a complete (517 m) sequence of lake sediments and impactites (317 m of lacustrine, post-impact sediments, a several m wide transition zone to the underlying impact breccias - 25 m suevite above 170 m monomict lithic breccia). The goals for drilling were: (1) to collect an unprecedented record of climate history in the terrestrial arctic, and (2) to facilitate study of the crater fill and the crater floor geology of this unique impact structure in a rare geological setting. Here we propose a petrographic (incl. shock deformation) and chemical (incl. projectile identification) project aimed at elucidating the formation of the impactite sequence in this drill core, and - in conjunction with numerical modeling based on these results (during phase 2) - at a better understanding of the impact processes involved in generation of this complex impact structure.
Das Projekt "Transformation of organic carbon in the terrestrial-aquatic interface" wird vom Umweltbundesamt gefördert und von Technische Universität Cottbus-Senftenberg, Institut für Boden, Wasser, Luft, Lehrstuhl für Gewässerschutz, Forschungsstelle Bad Saarow durchgeführt. The overarching goal of our proposal is to understand the regulation of organic carbon (OC) transfor-mation across terrestrial-aquatic interfaces from soil, to lotic and lentic waters, with emphasis on ephemeral streams. These systems considerably expand the terrestrial-aquatic interface and are thus potential sites for intensive OC-transformation. Despite the different environmental conditions of ter-restrial, semi-aquatic and aquatic sites, likely major factors for the transformation of OC at all sites are the quality of the organic matter, the supply with oxygen and nutrients and the water regime. We will target the effects of (1) OC quality and priming, (2) stream sediment properties that control the advective supply of hyporheic sediments with oxygen and nutrients, and (3) the water regime. The responses of sediment associated metabolic activities, C turn-over, C-flow in the microbial food web, and the combined transformations of terrestrial and aquatic OC will be quantified and characterized in complementary laboratory and field experiments. Analogous mesocosm experiments in terrestrial soil, ephemeral and perennial streams and pond shore will be conducted in the experimental Chicken Creek catchment. This research site is ideal due to a wide but well-defined terrestrial-aquatic transition zone and due to low background concentrations of labile organic carbon. The studies will benefit from new methodologies and techniques, including development of hyporheic flow path tubes and comparative assessment of soil and stream sediment respiration with methods from soil and aquatic sciences. We will combine tracer techniques to assess advective supply of sediments, respiration measurements, greenhouse gas flux measurements, isotope labeling, and isotope natural abundance studies. Our studies will contribute to the understanding of OC mineralization and thus CO2 emissions across terrestrial and aquatic systems. A deeper knowledge of OC-transformation in the terrestrial-aquatic interface is of high relevance for the modelling of carbon flow through landscapes and for the understanding of the global C cycle.
Das Projekt "Subproject: Deformation and syn-rift magmatism at the South Atlantic passive continental margin, Walvis Ridge area. A marine wide angle seismic and magnetotelluric experiment" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), Forschungsbereich 4 Dynamik des Ozeanbodens: Marine Geodynamik durchgeführt. The South Atlantic passive margin around the landfall of the Walvis Ridge hotspot track is a unique example of continental extension, breakup and oceanic basin development, assisted or dominated by hotspot-related magmatism. There is a prime opportunity to study the variation of the magmatic signal in space and time, and investigate the interrelation with rift-related deformation. A globally significant problem to be addressed here by observation of lithospheric structure, velocity and conductivity is whether magmatism drives continental deformation and breakup, or whether even rifting with copious hot-spot related magmatism is principally in response to crustal and lithospheric stretching. The approach is to quantify thickness and extent of dipping reflector sequences and interleaved sediments, identify deep fault zones, and characterize underplated magmatic rocks near the continent-ocean transition zone from a set of new set of wide angle seismic, magnetotelluric (MT), and supplementary gravity data. The funding requested is intended to support marine surveys of the Namibian margin where it is intersected by the Walvis Ridge, and to carry out post-cruise data processing. Our new integrated approach is geared towards achieving imaging of large magmatic bodies, of sediments interleaved in dipping reflector sequences, and large, potentially fluid filled fault zones. Data integration will be achieved through joint inversion of wide angle seismic, gravity and MT data. The project is part of a coordinated amphibian geophysical campaign within the SAMPLE program.
Das Projekt "Establishment of Teak plantations for high-value timber production in Ghana" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Arbeitsbereich für Weltforstwirtschaft und Institut für Weltforstwirtschaft des Friedrich-Löffler-Institut, Bundesforschungsinstitut für Tiergesundheit durchgeführt. Background and Objectives: The project area is located in the Ashanti Region of Ghana / West Africa in the transition zone of the moist semideciduous forest and tropical savannah zone. Main land use in this region is subsistence agriculture with large fallow areas. As an alternative land-use, forest plantations are under development by the Ghanaian wood processing company DuPaul Wood Treatment Ltd. Labourers from the surrounding villages are employed as permanent or casual plantation workers. Within three forest plantation projects of approximately 6,000 ha, DuPaul offers an area of 164 ha (referred to as Papasi Plantation) - which is mainly planted with Teak (Tectona grandis) - for research purposes. In return, the company expects consultations to improve the management for sustainable timber and pole production with exotic and native tree species. Results: In a first research approach, the Papasi Plantation was assessed in terms of vegetation classification, timber resources (in qualitative and quantitative terms) and soil and site conditions. A permanent sampling plot system was established to enable long-term monitoring of stand dynamics including observation of stand response to silvicultural treatments. Site conditions are ideally suited for Teak and some stands show exceptionally good growth performances. However, poor weed management and a lack of fire control and silvicultural management led to high mortality and poor growth performance of some stands, resulting in relative low overall growth averages. In a second step, a social baseline study was carried out in the surrounding villages and identified landowner conflicts between some villagers and DuPaul, which could be one reason for the fire damages. However, the study also revealed a general interest for collaboration in agroforestry on DuPaul land on both sides. Thirdly, a silvicultural management concept was elaborated and an improved integration of the rural population into DuPaul's forest plantation projects is already initiated. If landowner conflicts can be solved, the development of forest plantations can contribute significantly to the economic income of rural households while environmental benefits provide long-term opportunities for sustainable development of the region. Funding: GTZ supported PPP-Measure, Foundation
Das Projekt "Modeling of two-phase flow processes in strongly heterogeneous media using multi-rate mass transfer approaches" wird vom Umweltbundesamt gefördert und von Leibniz Universität Hannover, Institut für Strömungsmechanik und Umweltphysik im Bauwesen durchgeführt. Die Modellierung eines Fluides durch ein anderes, nicht mischbares und der Massentransfer zwischen den Phasen hat für viele geotechnische Anwendungen eine wichtige Bedeutung. Ein Beispiel ist die Injektion von superkritischem Kohlendioxid in brackisches Grundwasser in großen Tiefen (größer als 800 m). Die Darstellung des Einflusses von heterogenen Strukturen des Mediums, die nicht im numerischen Modell aufgelöst werden können, in das Modellkonzept ist dabei eine große Herausforderung. insbesondere wenn die Parameterkontraste groß sind. In diesem Antrag möchten wir Modellkonzepte für Zwei-Phasen Strömung auf großen Längenskalen erarbeiten, wobei wir uns auf die Übergangszone zwischen verdrängendem und verdrängtem Fluid (die Mischzone) fokussieren möchten. Die Mischzone ist die kritische Zone für beispielsweise Massenflüsse von gelösten Komponenten zwischen den Fluid Phasen. Basierend auf den Modellen, die die Mischzone quantifizieren, möchten wir in einem zweiten Schritt das Verhältnis des Volumens der Mischzone zur gesamten Grenzfläche zwischen den Fluiden untersuchen. Zur Herleitung solcher Modellkonzepte möchten wir Multi-Raten Massentransfer Modellansätze verwenden, die zur Beschreibung von Transport gelöster Stoffe in komplexen, stark heterogenen Medien mit stagnanten und mobilen Zonen des Strömungsfeldes entwickelt wurden. Diese Methoden waren sehr erfolgreich für lineare Transportprobleme. Wir möchten sie erweitern und auf das nichtlineare Zwei-Phasen Strömungsproblem anwenden.
Das Projekt "Natural Forest Management in Caracarai, Roraima, Brazil" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Arbeitsbereich für Weltforstwirtschaft und Institut für Weltforstwirtschaft des Friedrich-Löffler-Institut, Bundesforschungsinstitut für Tiergesundheit durchgeführt. Objectives: Sustainable management of tropical moist forests through private forest owners will become increasingly important. Media report that in Brazil, particularly in Amazonia, approx. 80 percent of the timber harvested is from illegal sources. Private management of forests according to internationally acknowledged standards offers an opportunity to significantly lower the portion of illegally cut timber. Moreover, it contributes significantly to the conservation of the Amazon forest. Private forest owners show a clear long-term commitment towards the implementation of management standards according that is ecologically compatible, socially acceptable and economically viable. The project area, a pristine forest in legal Amazonia in the transition zone between moist tropical forests and savannas (cerrado), is extremely diverse in floristic and faunistic terms. The institute cooperates with the private forest owner. Main tasks are to document the faunistic and floristic diversity, to calculate the Annual Allowable Cut and to elaborate concepts for site-specific silviculture. Results: To date (Oct. 2006) the following activities were started: - a comprehensive inventory system for planning at the FMU-level has been successfully introduced; - the inventory system for the annual coupe area has been designed and data for the first coupe are being processed; - the annual allowable cut is currently calculated based on the results of the above described inventories; - two fauna surveys are completed; one focusing on large mammals and one on the avi-fauna. A long-term monitoring concept to assess the influence of forest management on the faunistic diversity is currently under development; - forest zoning is completed applying terrestrial surveys and interpreting high-resolution satellite images; - a study on the use of Bethollethia excelsa-fruits (Brazil nuts) is currently implemented; - a study on timber properties of lesser known species is currently implemented.
Das Projekt "Die Untersuchung der Rolle der letzten Eiszeit für den gegenwärtigen und zukünftigen Meeresspiegelbeitrag der Antarktis mittels numerischer Simulationen" wird vom Umweltbundesamt gefördert und von Potsdam-Institut für Klimafolgenforschung e.V. durchgeführt. The project 'Modeling the role of the last ice age for the present and future sea-level contribution from Antarctica' will encompass the numerical simulation of at least four glacial cycles of the Antarctic sheet-shelf system using the Parallel Ice Sheet Model (PISM). The objective of the research plan is to determine the role of the past development of the Antarctic Ice Sheet for its sea-level contribution of the past and future century. To this end we investigate the influence of past climate evolution, especially the last deglaciation, on its present dynamic state: The ongoing changes in terms of mass balance, disregarding anthropogenic climate change, during the 20th and 21st centuries are influenced by the history of the advance and retreat of the ice during the last glacial cycles. Instead of aiming at a best-guess simulation, we will work on providing an ensemble of model simulations that incorporates uncertainties from climate boundary conditions and internal process-modeling and ice parameter choices. Apart from answering the above mentioned research question concerning the influence of the history of the ice sheet on its present day dynamics, we will also take an important step towards a new generation of projections of future ice discharge from Antarctica: It is important to know how much sea-level contribution, if any, is not caused by anthropogenic climate change. The program encompasses the development and short-term testing of physical improvements to the model that are needed in order to perform four glacial cycles (4GC) simulations and to provide a comprehensive ensemble. The currently implemented climate boundary conditions, both for the upper surface of the ice sheet and the underside of the ice shelves in contact with the ocean, will be examined and expanded to be suitable for 4GC-simulations. Process-based model components, concerning the numerical representation of the transition zone between ice sheet and ice shelf will be evaluated and improved. High-resolution nested simulation approaches will be developed for PISM in order to better resolve these crucial zones in order the further close the gap between finite differences models like PISM using shallow approximations of the stress balance and higher-order models. Sensitivity tests within 4GC-simulations will shed light on how the above mentioned new methods, climate boundary conditions in general and internal model parameters, influence the 4GC-simulation and ultimately the modeled present day state. An ensemble selection process will take place, excluding those parameter and climate-boundary combinations that are not conform to available geologic data for the past and observations of the present day state of the Antarctic ice sheet. This can be thought of as a 'blind selection' of the dynamic present-day state of the ice sheet...
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