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Found 460 results.

Ecosystem Engineering: Sediment entrainment and flocculation mediated by microbial produced extracellular polymeric substances (EPS)

Sediment erosion and transport is critical to the ecological and commercial health of aquatic habitats from watershed to sea. There is now a consensus that microorganisms inhabiting the system mediate the erosive response of natural sediments ('ecosystem engineers') along with physicochemical properties. The biological mechanism is through secretion of a microbial organic glue (EPS: extracellular polymeric substances) that enhances binding forces between sediment grains to impact sediment stability and post-entrainment flocculation. The proposed work will elucidate the functional capability of heterotrophic bacteria, cyanobacteria and eukaryotic microalgae for mediating freshwater sediments to influence sediment erosion and transport. The potential and relevance of natural biofilms to provide this important 'ecosystem service' will be investigated for different niches in a freshwater habitat. Thereby, variations of the EPS 'quality' and 'quantity' to influence cohesion within sediments and flocs will be related to shifts in biofilm composition, sediment characteristics (e.g. organic background) and varying abiotic conditions (e.g. light, hydrodynamic regime) in the water body. Thus, the proposed interdisciplinary work will contribute to a conceptual understanding of microbial sediment engineering that represents an important ecosystem function in freshwater habitats. The research has wide implications for the water framework directive and sediment management strategies.

Schwerpunktprogramm (SPP) 1315: Biogeochemische Grenzflächen in Böden; Biogeochemical Interfaces in Soil, Highly-resolved imaging in artificial and natural soils to yield dynamics and structure of interfaces from oxygen, pH and water content

In soils and sediments there is a strong coupling between local biogeochemical processes and the distribution of water, electron acceptors, acids, nutrients and pollutants. Both sides are closely related and affect each other from small scale to larger scale. Soil structures such as aggregates, roots, layers, macropores and wettability differences occurring in natural soils enhance the patchiness of these distributions. At the same time the spatial distribution and temporal dynamics of these important parameters is difficult to access. By applying non-destructive measurements it is possible to overcome these limitations. Our non-invasive fluorescence imaging technique can directly quantity distribution and changes of oxygen and pH. Similarly, the water content distribution can be visualized in situ also by optical imaging, but more precisely by neutron radiography. By applying a combined approach we will clarify the formation and architecture of interfaces induces by oxygen consumption, pH changes and water distribution. We will map and model the effects of microbial and plant root respiration for restricted oxygen supply due to locally high water saturation, in natural as well as artificial soils. Further aspects will be biologically induced pH changes, influence on fate of chemicals, and oxygen delivery from trapped gas phase.

Forschergruppe (FOR) 1525: INUIT - Ice Nuclei research UnIT, Heterogende Eisnukleation ausgelöst durch poröse Materialien

Die Nukleation von Eispartikeln spielt eine wichtige Rolle bei der Wolken- und Niederschlagsbildung, mit Konsequenten für die atmosphärische Chemie, die Wolkenphysik und das Erdklima. Für eine Quantifizierung und Vorhersage des Einflusses von Wolken in Wettervorhersage- und Klimamodellen muss die Bildung von Eispartikeln daher in einer realistischen Art und Weise beschrieben werden. Einer der wichtigen Bildungsmechanismen ist dabei die heterogene Eisnukleation im Immersionsmodus, bei dem Eis an der Oberfläche eines in einem wässrigen Tröpfchen suspendierten Eiskeims - zum Beispiel eines Mineralstaub- Partikels - gebildet wird. Wir werden im Rahmen dieses Forschungsprojekts zahlreiche Gefrierexperimente im Immersionsmodus durchführen. So werden eine Reihe verschiedener, als Aerosolpartikel in der Atmosphäre vorkommende Materialien auf ihre Eisnukleationseigenschaften hin untersucht werden. Insbesondere sollen hier die Temperatur- und Zeitabhängigkeit der von diesen Materialien ausgelösten Eisnukleation quantifiziert werden. Dabei werden wir spezielles Augenmerk auf die systematische Untersuchung der von porösen Materialien ausgelösten Eisnukleation legen. Es sollen sowohl synthetische Materialien wie beispielsweise mesoporöse Silikate untersucht werden, als auch natürlich vorkommende Materialien wie etwa mikroporöse Zeolithe.

Drivers and mechanisms of 13C discrimination in Cleistogenes squarrosa (C4) - reducing uncertainties on bundle sheath leakiness

The energetic efficiency of C4 photosynthesis is strongly affected by bundle sheath leakiness, which is commonly assessed with the 'linear version' of the Farquhar model of 13C discrimination, and leaf gas exchange and 13C composition data. But, the linear Farquhar model is a simplification of the full mechanistic theory of ? in C4 plants, potentially generating errors in the estimation of leakiness. In particular, post-photosynthetic C isotope fractionation could cause large errors, but has not been studied in any detail. The present project aims to improve the understanding of the ecological and developmental/physiological factors controlling discrimination and leakiness of the perennial grass Cleistogenes squarrosa. C. squarrosa is the most important member of the C4 community which has spread significantly in the Mongolia grasslands in the last decades. It has an unusually high and variable discrimination, which suggests very high (and potentially highly variable) leakiness. Specifically, we will conduct the first systematic study of respiratory 13C fractionation in light and dark at leaf- and stand-scale in this C4 species, and assess its effect on discrimination and estimates of leakiness. These experiments are conducted in specialized 13CO2/12CO2 gas exchange mesocosms using ecologically relevant scenarios, testing specific hypotheses on effects of environmental drivers and plant and leaf developmental stage on discrimination and leakiness.

Monsunvariabilität in SE-China - der Huguang-Maarsee (Huguangyan)

Südchina, insbes. die Provinz Guandong, ist eines der am dichtesten besiedelten Gebiete der Erde. Positive Konsequenz dieser Ballung ist eine äußerst dynamische Wirtschaftsentwicklung, aber gerade diese von subtropischem Monsunklima geprägte Region ist auch immer wieder Ausgangspunkt für sich schnell und zunehmend global ausbreitende epidemische Krankheiten wie zuletzt SARS. Mit der globalen Erwärmung einhergehende Klimaveränderungen könnten sich für diese Region insbesondere durch Veränderungen der Häufigkeit und Intensität tropischer Wirbelstürme, aber auch Änderungen der Niederschlagsmenge- und Intensität bemerkbar machen. Im Gegensatz zu den schon recht umfangreichen Datensätzen aus der Südchinesischen See (SCS) gibt es bisher jedoch nur sehr wenige terrestrische Paläoklimaarchive aus der Region, die Klimaveränderungen während des Holozäns, des Spätglazials oder Glazials hochauflösend dokumentieren. Wir haben deshalb einen an der nördlichen Küste der SCS gelegenen Maarsee ausgewählt, um über die Analyse von Proxydaten aus Seesedimenten solche Paläo-Klimavariationen zu untersuchen. Aus dem Sediment des Huguang-Maarsees wurden mittels Usinger-Präzisionsstechtechnik von einem Floss aus insgesamt 7 Sedimentsequenzen gewonnen, von denen die tiefste bis 57 m unter den Seeboden reicht. Die zeitliche Einstufung der Profile wurde mit Hilfe von 17 Radiokohlenstoff-Datierungen vorgenommen und ergab ein extrapoliertes Maximalalter von ca. 78.000 Jahren. Ein breites Spektrum aus sedimentologischen, geochemischen, paläo- und gesteinsmagnetischen sowie palynologischen Methoden kam sodann zum Einsatz, um die Paläo-Umweltbedingungen, die natürlich immer das entsprechende Klima widerspiegeln, während dieses Zeitraumes zu rekonstruieren. Überraschenderweise ergab sich ein von vielen bekannten Klimaprofilen der Nordhemisphäre (insbes. des Atlantikraumes, aber auch mariner Kerne aus dem Indik und Südostasien) abweichendes Muster. Im Gegensatz zu dem bekannten Grundmuster eines vergleichsweise stabilen Klimas während des Holozäns und stärkerer Schwankungen während des letzten Glazials weisen die Daten aus dem Huguang-Maarsee für das letzte Glazial im Zeitraum zwischen 15.000 und 40.000 Jahren auf relativ stabile Umweltbedingungen hin. Die älteren Bereiche zwischen 40.000 und ca. 78.000 Jahren haben durch Eintrag von umgelagertem Torf eine eher lokale Komponente und sind somit für den regionalen und globalen Vergleich ungeeignet. Das Holozän hingegen zeichnet sich durch hohe Schwankungsamplituden vieler Proxydaten (Karbonatgehalt, magnetische Suszeptibilität, organischer Kohlenstoff, Trockendichte, gesteinsmagnetische Parameter, Redox-Verhältnisse) aus, die auf ein recht variables Klima hinweisen. Besonders interessant ist die Übergangsphase vom Glazial zum Holozän, die bei etwa 15.000 Jahren vor heute in etwa zeitgleich mit dem beobachteten stärksten Meeresspiegelanstieg der Südchinesischen See einsetzt und eine abrupte Intensitätszunahme des Sommermonsuns anzeigt

European Investment Bank - Water Management

BACKGROUND: The Kingdom of Jordan belongs to the ten water scarcest countries in the world, and climate change is likely to increase the frequency of future droughts. Jordan is considered among the 10 most water impoverished countries in the world, with per capita water availability estimated at 170 m per annum, compared to an average of 1,000 m per annum in other countries. Jordan Government has taken the strategic decision to develop a conveyor system including a 325 km pipe to pump 100 million cubic meters per year of potable water from Disi-Mudawwara close to the Saudi Border in the south, to the Greater Amman area in the north. The construction of the water pipeline has started end of 2009 and shall be finished in 2013. Later on, the pipeline could serve as a major part of a national water carrier in order to convey desalinated water from the Red Sea to the economically most important central region of the country. The conveyor project will not only significantly increase water supplies to the capital, but also provide for the re-allocation of current supplies to other governorates, and for the conservation of aquifers. In the context of the Disi project that is co-funded by EIB two Environmental and Social Management Plans have been prepared: one for the private project partners and one for the Jordan Government. The latter includes the Governments obligation to re-balance water allocations to irrigation and to gradually restore the protected wetlands of Azraq (Ramsar site) east of Amman that has been depleted due to over-abstraction by re-directing discharge of highland aquifers after the Disi pipeline becomes operational. The Water Strategy recognizes that groundwater extraction for irrigation is beyond acceptable limits. Since the source is finite and priority should be given to human consumption it proposes to tackle the demand for irrigation through tariff adjustments, improved irrigation technology and disincentive to water intensive crops. The Disi aquifer is currently used for irrigation by farms producing all kinds of fruits and vegetables on a large scale and exporting most of their products to the Saudi and European markets and it is almost a third of Jordan's total consumption. The licenses for that commercial irrigation were finished by 2011/12. Whilst the licenses will be not renewed the difficulty will be the enforcement and satellite based information become an important supporting tool for monitoring. OUTLOOK: The ESA funded project Water management had the objective to support the South-North conveyor project and the activities of EIB together with the MWI in Jordan to ensure the supply of water for the increasing demand. EO Information provides a baseline for land cover and elevation and support the monitoring of further stages. usw.

Schwerpunktprogramm (SPP) 1158: Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; Bereich Infrastruktur - Antarktisforschung mit vergleichenden Untersuchungen in arktischen Eisgebieten, Biological soil crust algae in the polar regions - biodiversity, genetic diversity and ecosystem resilience under global change scenarios

Terrestrial green algae and cyanobacteria are typical and abundant components of biological soil crusts in the Polar Regions. These communities form water-stable aggregates that have important ecological roles in primary production, nitrogen fixation, nutrient cycling, water retention and stabilization of soils. Although available data on green algae and cyanobacteria are generally very limited for the Arctic and Antarctica, their functional importance as ecosystem developers in nutrient poor environments is regarded as high. Therefore, the main goal of the interdisciplinary project is, for the first time, a precise evaluation of their 1.) Biodiversity as well as of 2.) The infra-specific genetic diversity, 3.) ecophysiological performance and 4.) transcriptomics of the most abundant taxa in biological soil crusts isolated from the Antarctic Peninsula and Arctic Svalbard. Biodiversity will be investigated using a classical culture approach in combination with molecular-taxonomical methods as well as with metagenomics. The infra-specific genetic diversity of the most abundant green algae and cyanobacteria will be studied using fingerprinting techniques, and a range of selected populations characterized in relation to their physiological plasticity. Temperature and water availability, two key environmental factors for terrestrial organisms, are currently changing in Polar Regions due to global warming, and hence their effect on growth and photosynthesis response patterns will be comparatively investigated. The data will indicate whether and how global change influence population structure and ecological performance of key organisms in polar soil crusts, and help to make predictions on the future significance of the ecological functions of these pioneer communities. Such a multiphasic approach has never been applied before to soil algae and cyanobacteria in both Polar Regions, and hence represents one of the key innovations of this proposal.

3R-Studie - Reduce, Reuse, Recycle für die G8-Staaten

bifa hat ein Vorhaben für die G8- Staaten bearbeitet, in dem die Entwicklungen in Deutschland innerhalb der neun Handlungsfelder ( Actions ) des Kobe 3R Action Plan dargestellt werden. Mit der 3R-Initiative beabsichtigen die G8-Staaten seit 2004 eine bessere Verankerung der Nachhaltigkeit im Umgang mit Rohstoffen durch die stärkere Förderung der drei Prinzipien Reduce, Reuse, Recycle , abgekürzt 3R , in den nationalen Abfallwirtschaftspolitiken. Im Rahmen der Beauftragung untersuchte bifa, welche Punkte aus dem Kobe 3R Action Plan bereits hinreichend durch bestehende Entwicklungen bzw. ergriffene Maßnahmen abgedeckt sind, bei welchen Aktionen noch Lücken bestehen und wie diese Lücken gefüllt werden können. Legt man die drei Zielsetzungen des Kobe 3R Action Plan und die ihnen zugeordneten Handlungsfelder als Prüfraster über die deutsche Abfallwirtschaftspolitik, lässt sich ein sehr hoher Erfüllungsgrad feststellen. Ein erheblicher Teil der vorgeschlagenen Handlungsoptionen war in Deutschland bereits vor 2008 durch konkrete Maßnahmen umgesetzt worden. Für einen anderen Teil wiederum lässt sich der Ursprung, z. B. in Form eines ersten Gesetzentwurfs, auf die Zeit vor 2008 zurückdatieren, die Umsetzung durch die Veröffentlichung im Bundesgesetzblatt aber fand 2008-2011 statt. Einige Regelungen setzen Richtlinien oder Verordnungen der EU, die ihrerseits zum Teil auf Bestrebungen Deutschlands hin zustande kamen, in nationales Recht um. Mit dem in einer fortgeschrittenen Version vorliegenden Entwurf eines novellierten Kreislaufwirtschaftsgesetzes vollzieht Deutschland einen weiteren wichtigen Schritt hin zu einer Abfallwirtschaft, deren Markenzeichen insbesondere eine hohe Ressourceneffizienz ist. Dennoch verbleiben Optimierungspotenziale, zu deren Ausschöpfung bifa Vorschläge für das Bundesumweltministerium erarbeitet hat. Im Zuge des Projekts analysierte bifa u. a. die Importe und Exporte notifizierungspflichtiger Abfälle. Der Saldo hat sich den bifa-Analysen zufolge seit 1998 umgekehrt: Wurden 1998 noch etwa doppelt so viel notifizierungspflichtige Abfälle exportiert wie importiert, hat sich der Import seitdem vervierfacht und die Exporte sind sogar leicht gesunken. Ein wichtiger Grund ist die Verfügbarkeit von Behandlungs- und Verwertungskapazitäten von hoher Leistungsfähigkeit in Deutschland. Die Schadstoffentfrachtung von Abfällen aus Ländern mit einer wenig entwickelten Entsorgungsinfrastruktur führt jedoch innerhalb der deutschen Öffentlichkeit immer wieder zu Kontroversen. Methoden: Analyse und Moderation sozialer Prozesse.

Ecology and Population Biology of Armillaria mellea s.l.

The basidiomycete Armillaria mellea s.l. is one of the most important root rot pathogens of forest trees and comprises several species. The aim of the project is to identify the taxa occurring inSwitzerland and to understand their ecological behaviour. Root, butt and stem rots caused by different fungi are important tree diseases responsible for significant economic losses. Armillaria spp. occur world-wide and are important components of many natural and managed forest ecosystems. Armillaria spp. are known saprothrophs as well as primary and secondary pathogens causing root and butt rot on a large number of woody plants, including forest and orchard trees as well as grape vine and ornamentals. The identification of several Armillaria species in Europe warrants research in the biology and ecology of the different species. We propose to study A. cepistipes for the following reasons. First, A. cepistipes is dominating the rhizomorph populations in most forest types in Switzerland. This widespread occurrence contrasts with the current knowledge about A. cepistipes, which is very limited. Second, because the pathogenicity of A. cepistipes is considered low this fungus has the potential for using as an antagonist to control stump colonising pathogenic fungi, such as A. ostoyae and Heterobasidion annosum. This project aims to provide a better understanding of the ecology of A. cepistipes in mountainous Norway spruce (Picea abies) forests. Special emphasis will be given to interactions of A. cepistipes with A. ostoyae, which is a very common facultative pathogen and which often co-occurs with A. cepistipes. The populations of A. cepistipes and A. ostoyae will be investigated in mountainous spruce forests were both species coexist. The fungi will be sampled from the soil, from stumps and dead wood, and from the root system of infected trees to determine the main niches occupied by the two species. Somatic incompatibility will be used to characterise the populations of each species. The knowledge of the spatial distribution of individual genets will allow us to gain insights into the mode of competition and the mode of spreading. Inoculation experiments will be used to determine the variation in virulence expression of A. cepistipes towards Norway spruce and to investigate its interactions with A. ostoyae.

Native plants and mycorrhizal fungi in wind erosion control in the Kailash-Manasarovar region (Tibet, China)

We study the effects of plants and root-associated fungi on wind erosion within the alpine environment of Tibet. China is one of the countries most affected by desertification processes and Tibet, in particular, a key region in desertification combat. The presented project focuses on the Barkha Plain surrounded by Mount Kailash and the Lake of Manasarovar (Ngari Prefecture). This Western Tibet region experienced little scientific attention but, nowadays, faces rapidly increasing touristic activities and expanding local settlements associated with socio-economic changes that are serious threats to the delicate ecological balance and potential triggers of desertification. It exists almost unanimous agreement that revegetation is the most efficient and promising strategy to combat wind erosion and desertification in the long term. However, re-colonising success is often poor, mainly under extreme environmental conditions. Compared to conventional practices, the approach of the presented project attains better accordance with natural succession processes and promises acceleration of both plant and soil development and, conclusively, more efficient desertification control. The project assesses the potential of native plants and symbiotic fungi to control wind erosion and desertification processes. It aims to identify key plants and fungi that increase soil aggregate stability and efficiently drive succession into a natural and self-maintaining cycle of the ecosystem. Furthermore, it provides crucial information for implementing environmentally compatible and cost-effective measures to protect high-elevation ecosystems against desertification. Within three successional stages (early, intermediate, late), field investigations are performed on the basis of Modified-Whittaker plots. Classic methods of vegetation analysis and myco-sociology are combined with analysis of distribution patterns at different scales (patchiness, connectivity). Comprehensive soil analysis is performed comprising grain size distribution, aggregate stability, pH as well as water and nutrient contents. Additionally, important parameters of wind erosion are measured concurrently and continuously to assess their magnitude and variability with respect to vegetation and soil at different levels of development. The parameters addressed, include sediment transport, air temperature, radiation, precipitation, relative humidity as well as speed and direction of wind. Surface moisture is recorded periodically and roughness described. Species and environmental parameters are checked for spatial correlation. Cutting edge technologies are applied in laboratory work, comprising molecular methods for fungal species identification and micro-tomography to analyse soil structure. Furthermore, successfully cultivated fungi and plants are subject of synthesis experiments and industrial propagation in view of practical implementation in restoration measures.

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