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.
Die Europäische Kommission wird voraussichtlich eine Folgenabschätzung sowie einen Gesetzesentwurf zur indirekten Landnutzungsänderung (ILUC) in Zusammenhang mit der Biokraftstoffproduktion veröffentlichen. Die Einführung einer EU-Richtlinie zur indirekten Landnutzungsänderung in der Richtlinie für Erneuerbare Energien (RED) und der Richtlinie zur Kraftstoffqualität (FQD), hat möglicherweise Einfluss auf derzeitige Investitionen und Arbeitsplätze in der europäischen Biokraftstoffindustrie. Im Auftrag der Umweltorganisation Transport & Environment hat Ecofys untersucht, inwieweit der Biokraftstoffsektor unter dem Gesichtspunkt der Bestandswahrung gegen die Einführung einer ILUC-Richtlinie auf EU-Ebene geschützt werden kann. Dies wird mit dem Begriff 'Grandfathering' beschrieben. Der Bericht beginnt mit einem Überblick über den EU Biokraftstoffmarkt und -sektor. Er analysiert die verschiedenen Auswirkungen möglicher ILUC Maßnahmen in Hinblick auf den Sektor und geht der Frage nach, inwieweit gegenwärtige Investitionen und Arbeitsplätze geschützt werden müssen. In einem zweiten Schritt untersucht der Bericht die Grandfathering Klausel, die aktuell in der RED und FQD Richtlinie enthalten ist, sowie weitere mögliche Grandfathering Optionen. Die Studie kommt zu dem Schluss, dass die Einführung einer ILUC Politikmaßnahme bei gleichzeitigem Erhalt der Arbeitsplätze und der Investitionen in Biokrafstoffproduktion möglich ist, wenn das Biokraftstoffverbrauchsniveau von 2010-2012 bis zum Jahr 2020 von der ILUC Richtlinie ausgenommen wird. Dies würde bedeuten, dass eine mögliche ILUC Richtlinie sich lediglich auf die zukünftige Biokraftsoffproduktion ab 2020 bezieht. Die ILUC-Maßnahme würde den gesamten Biokraftstoffverbrauch in der EU nicht deutlich verringern, da die Ziele der RED und FQD für 2020 unverändert bleiben. Dennoch könnten auf den EU Biodieselsektor Herausforderungen zukommen, wenn z. B. neue ILUC-Faktoren eingeführt oder der Mindestschwellenwert für Treibhausgasausstoß angehoben würde. Ein Grandfathering des derzeitigen Biokraftstoffverbrauchs würde dem entgegenwirken und heutige Investitionen und Arbeitsplätze sichern. Die Ergebnisse der Studie wurden am 22. März 2012 dem Europäischen Parlament vorgestellt.
In the Bavarian Forest National Park a brief, but intense storm event on 1 August 1983 created large windfall areas. The windfall ecosystems within the protection zone of the park were left develop without interference; outside this zone windfall areas were cleared of dead wood but not afforested. A set of permanent plots (transect design with 10 to 10 m plots) was established in 1988 in spruce forests of wet and cool valley bottoms in order to document vegetation development. Resampling shall take place every five years; up to now it was done in 1993 and 1998. On cleared areas an initial raspberry (Rubus idaeus) shrub community was followed by pioneer birch (Betula pubescens, B. pendula) woodland, a sequence well known from managed forest stands. In contrast to this, these two stages were restricted to root plates of fallen trees in uncleared windfalls; here shade-tolerant tree species of the terminal forest stages established rather quickly from saplings that had already been present in the preceeding forest stand. Soil surface disturbances are identified to be causal to the management pathway of forest development, wereas the untouched pathway is caused by relatively low disturbance levels. The simulation model FORSKA-M is used to analyse different options of further stand development with a simulation time period of one hundred years.
Early generation plant breeding trials are often laid out according to unreplicated designs. Replicated checks may be used for error control, for example in augmented designs based on an incomplete block design for checks which are augmented with unreplicated entries. Traditional augmented designs require considerable resources to be spent on genotypes that are not themselves of interest. Therefore, it has been suggested to replace checks with partially replicated entries, leading to so-called prep designs. In the present proposal we suggest combining both ideas to develop what we call augmented prep designs. A non-trivial design problem arises when trials are to be performed at multiple locations. The main challenge then is how to augment the blocks so as to balance the number of pairwise concurrences. This task can be tackled in different ways based on the use (-arrays which are well-known as the basis for (-designs in fully replicated experiments. Furthermore, we also explore the refinement of designs when analysis by spatial models is envisioned. Robustness of the designs to the presence of genotype-environment interaction is also investigated.
Mikroorganismen sind im Boden, in kryptogamen Gemeinschaften und in der Atmosphäre von zentraler Bedeutung. Verschiedene Spezies von Bakterien, Pilzen, Flechten und Pollen wurden bereits als Eiskeime, welche eine Eisbildung bei relativ hohen Temperaturen initiieren können, identifiziert, und besonders biologische Bestandteile aus dem Boden sind eine vermutlich bedeutsame Quelle atmosphärischer Eiskeime. Die genauen Quellen biologischer Eiskeime in der Atmosphäre sind jedoch kaum bekannt, obwohl ein potentieller Beitrag dieser, zur Eis- und Niederschlagsbildung mittlerweile von verschiedenen Studien untermauert wird. Aktuelle Untersuchungen verschiedener Boden- und Luftproben zeigen Hinweise, dass verschiedene eisaktive Pilze unterschiedlicher Phyla nicht nur im Boden und in der Luft vorhanden sind, sondern auch häufig in der kultivierbaren Fraktion vorkommen können. Aus diesem Grund befasst sich das vorgeschlagene Projekt mit der Suche nach weiteren bisher unbekannten eisaktiven Mikroorganismen und Bestandteilen aus dem Boden, von Pflanzen und kryptogamen Gemeinschaften und mit der Erforschung ihres Einflusses auf die Eiskeimaktivität des Bodens. Die nötigen Methoden für ein Screening verschiedenster Kulturen z.B. von Cyanobakterien sind in unserem Labor gut etabliert. Zudem sollen die jeweiligen Eiskeime der neu gefundenen eisaktiven Organismen auf molekularer Ebene charakterisiert werden.
SP0 is conceived for coordination of the ICON research, for internal and external scientific exchange as well as for investigating development pathways of land use on the Philippines. The SP0 team will supervise the project activities as a whole, including reporting and final synthesis. It will design the ICON homepage, establish and maintain a web-based database and present the project and its results in scientific forums and public media. It will organize collaboration and scientific exchange with international networks dealing with atmospheric processes, global carbon, nitrogen, water and energy cycles, and long-term ecological research. Specifically, SP0 is devoted to ensuring a sound integration of the ICON project within the scientific communities of Germany and SE Asia. Supported by the ICON local research coordinator based at and employed by IRRI, it will coordinate with the IRRI farm management to assist other ICON subprojects with field setup, routine data collection and technical backstopping.
The development of sustainable and efficient energy conversion processes at interfaces is at the center of the rapidly growing field of basic energy science. How successful this challenge can be addressed will ultimately depend on the acquired degree of molecular-level understanding. In this respect, the severe knowledge gap in electro- or photocatalytic conversions compared to corresponding thermal processes in heterogeneous catalysis is staggering. This discrepancy is most blatant in the present status of predictive-quality, viz. first-principles based modelling in the two fields, which largely owes to multifactorial methodological issues connected with the treatment of the electrochemical environment and the description of the surface redox chemistry driven by the photo-excited charges or external potentials.Successfully tackling these complexities will advance modelling methodology in (photo)electrocatalysis to a similar level as already established in heterogeneous catalysis, with an impact that likely even supersedes the one seen there in the last decade. A corresponding method development is the core objective of the present proposal, with particular emphasis on numerically efficient approaches that will ultimately allow to reach comprehensive microkinetic formulations. Synergistically combining the methodological expertise of the two participating groups we specifically aim to implement and advance implicit and mixed implicit/explicit solvation models, as well as QM/MM approaches to describe energy-related processes at solid-liquid interfaces. With the clear objective to develop general-purpose methodology we will illustrate their use with applications to hydrogen generation through water splitting. Disentangling the electro- resp. photocatalytic effect with respect to the corresponding dark reaction, this concerns both the hydrogen evolution reaction at metal electrodes like Pt and direct water splitting at oxide photocatalysts like TiO2. Through this we expect to arrive at a detailed mechanistic understanding that will culminate in the formulation of comprehensive microkinetic models of the light- or potential-driven redox process. Evaluating these models with kinetic Monte Carlo simulations will unambiguously identify the rate-determining and overpotential-creating steps and therewith provide the basis for a rational optimization of the overall process. As such our study will provide a key example of how systematic method development in computational approaches to basic energy sciences leads to breakthrough progress and serves both fundamental understanding and cutting-edge application.
(1) Terrestrische Biota der Antarktis sind durch geografische Isolation und inselhafte Verteilung geprägt. Die isolierte Lage der Antarktis und die Beschränkung auf weit voneinander entfernte kleine Habitatflecken haben zu einem hohen Endemiten-Anteil und einer starken Regionalisierung der Fauna und Flora geführt. Genetische Differenzierung, lokale Anpassung und die Evolution kryptischer Arten sind die Folge. Die Biodiversitäts-Konvention (CBD) betrachtet genetische Diversität als einen Eckpfeiler biologischer Vielfalt und stellt sie damit in eine Reihe mit der Diversität von Arten und Ökosystemen. Durch Einschleppung ortsfremder Arten und Homogenisierung bislang getrennter Genpools bedroht der Mensch jedoch zunehmend diese Isolation und genetische Differenzierung vieler antarktischer Biota. (2) Obwohl Flechten als wichtigste Primärproduzenten antarktische terrestrische Lebensräume dominieren, fehlen zurzeit Daten zu ihrer genetischen Struktur und Diversität. Der Umfang inter- und intrakontinentalen Genflusses ist bisher völlig unbekannt. Es ist deswegen derzeit unmöglich, den aktuellen und zukünftigen menschlichen Einfluss auf antarktische Flechtenpopulationen auch nur annähernd abzuschätzen.(3) Wir schlagen vor, mittels molekulargenetischer Daten die populationsgenetische Struktur von sechs weit verbreiteten Flechtenarten mit unterschiedlichen Ausbreitungsstrategien zu untersuchen. Dabei soll die Nullhypothese überprüft werden, dass Flechtenpopulationen genetisch nicht differenziert sind. Zusätzlich wollen wir abschätzen, ob menschliche Aktivitäten zur Einschleppung ortsfremder Arten oder Genotypen und zur Homogenisierung von Genpools beitragen. Hierfür sollen Lokalitäten mit hohem und niedrigem menschlichen Einfluss verglichen werden. Das Projekt schafft damit unverzichtbare Grunddaten für die Entwicklung von Schutzstrategien in der Antarktis.
The majority of the worlds forests has undergone some form of management, such as clear-cut or thinning. This management has direct relevance for global climate: Studies estimate that forest management emissions add a third to those from deforestation, while enhanced productivity in managed forests increases the capacity of the terrestrial biosphere to act as a sink for carbon dioxide emissions. However, uncertainties in the assessment of these fluxes are large. Moreover, forests influence climate also by altering the energy and water balance of the land surface. In many regions of historical deforestation, such biogeophysical effects have substantially counteracted warming due to carbon dioxide emissions. However, the effect of management on biogeophysical effects is largely unknown beyond local case studies. While the effects of climate on forest productivity is well established in forestry models, the effects of forest management on climate is less understood. Closing this feedback cycle is crucial to understand the driving forces behind past climate changes to be able to predict future climate responses and thus the required effort to adapt to it or avert it. To investigate the role of forest management in the climate system I propose to integrate a forest management module into a comprehensive Earth system model. The resulting model will be able to simultaneously address both directions of the interactions between climate and the managed land surface. My proposed work includes model development and implementation for key forest management processes, determining the growth and stock of living biomass, soil carbon cycle, and biophysical land surface properties. With this unique tool I will be able to improve estimates of terrestrial carbon source and sink terms and to assess the susceptibility of past and future climate to combined carbon cycle and biophysical effects of forest management. Furthermore, representing feedbacks between forest management and climate in a global climate model could advance efforts to combat climate change. Changes in forest management are inevitable to adapt to future climate change. In this process, is it possible to identify win-win strategies for which local management changes do not only help adaptation, but at the same time mitigate global warming by presenting favorable effects on climate? The proposed work opens a range of long-term research paths, with the aim of strengthening the climate perspective in the economic considerations of forest management and helping to improve local decisionmaking with respect to adaptation and mitigation.
This subproject aims at the development of spectral electrical impedance tomography (EIT) as a non-destructive tool for the imaging, characterization and monitoring of root structure and function in the subsoil at the field scale. The approach takes advantage of the capacitive properties of the soil-root interface associated with induced electrical polarization processes at the root membrane. These give rise to a characteristic electrical signature (impedance spectrum), which is measurable in an imaging framework using EIT. In the first project phase, the methodology is developed by means of controlled rhizotron experiments in the laboratory. The goal is to establish quantitative relationships between characteristics of the measured impedance spectra and parameters describing root system morphology, root growth and activity in dependence on root type, soil type and structure (with/without biopores), as well as ambient conditions. Parallel to this work, sophisticated EIT inversion algorithms, which take the natural characteristics of root system architecture into account when solving the inherent inverse problem, will be developed and tested in numerical experiments. Thus the project will provide an understanding of electrical impedance spectra in terms of root structure and function, as well as specifically adapted EIT inversion algorithms for the imaging and monitoring of root dynamics. The method will be applied at the field scale (central field trial in Klein-Altendorf), where non-destructive tools for the imaging and monitoring of subsoil root dynamics are strongly desired, but at present still lacking.
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