Wednesday, 23 January 2008

Ph.D. oppourtunities at Gottingen University

There is an announcement for 12 PhD positions in University of Goettingen, Germany. May be any of you have great interest in following topics:
A1: Functional roles of ecto- and arbuscular mycorrhiza in deciduous forest trees and their role for nutrient competition and productivity Project leader: Prof. Dr. A. Polle, Forstbotanisches Institut, Büsgenweg 2, 37077 Göttingen, Germany
Aims of the project: To analyse functional roles of ectomycorrhiza in comparison with arbuscular mycorrhiza for N and P uptake and root productivity. Methods: Molecular biology, histochemistry, physiology including application of stable and radioactive isotopes.
A2: Mechanisms driving insect community composition and multitrophic interactions in mixed deciduous forests.
Project leader: Prof. Dr. Teja Tscharntke, Dr. Christoph Scherber, Agroecology, University of Göttingen, Waldweg 26, 37073 Göttingen; E-Mail: ttschar@gwdg.de, christoph.scherber@agr.uni-goettingen.de
Aims of the project: Analyze effects of tree species diversity on insect communities and multitrophic interactions between plants, pollinators, herbivores and their enemies. The work will include quantification of a diversity of interactions and field experiments with a main focus on herbs. Methods: Canopy research by use of a mobile elevator, standardised insect sampling, taxonomy, enclosure experiments, chemical analysis of leaf quality and volatiles.
A3: Mechanisms determining effects of tree species diversity on soil fauna in the rhizosphere and the soil-litter interface Project leader: N.N. (Dr. Christian Platner, Prof. Dr. Matthias Schaefer), Abteilung Ökologie, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Berliner Str. 28, 37073 Göttingen; E-Mail: mschaef@gwdg.de
Aims of the project: Study of the diversity of soil mesofauna and microfauna groups in relation to tree species diversity; analysis of litter decomposition and the carbon translocation between plants, fauna and soil; study of the interactions between microflora and fauna in the rhizosphere and the soil-litter system.
Methods: Sampling of soil fauna; field and lab experimentation; food web and element balance analysis with stable isotopes; measurement of litter decomposition and root exudates.
B1: Mechanisms leading to niche partitioning in carbon and nitrogen uptake between tree species in a mixed deciduous forest
Project leader: Prof. Dr. Leuschner, Plant Ecology, Untere Karspüle 2, 37073 Göttingen, Germany, e-mail: cleusch@gwdg.de; Prof. Dr. Frank Thomas, Universität Trier,Fachbereich VI,Abt. Geobotanik, Campus II, Raum H117, Behringstr. 21, D-54296 Trier, e-mail: thomasf@uni-trier.de
Aims of the project: Characterization of photosynthesis capacities and respiration of 5 tree species using a model of leaf gas-exchange (Farquhar et al. 1980). Investigation of the role of tree species diversity for the production of above-ground biomass and nutrient pools. Methods: Gas-exchange measurements using a mobile elevator to reach mature tree canopies. Hemispherical photography; Parameterization of a mechanistic leaf gas-exchange model. Measurement of wood and leaf production, leaf area index, nutrient uptake, and nutrient concentrations.
B2: Carbon and nitrogen turnover and competition processes in the rhizosphere of deciduous forests with contrasting tree species diversity Project leader: Prof. Dr. Christoph Leuschner, Plant Ecology, University of Göttingen, Untere Karspüle 2, 37073 Göttingen; E-mail: cleusch@gwdg.de
Aims of the project: Investigating the role of tree species diversity and spatial distribution of tree species on the size and structure of the fine root system and its carbon and nitrogen turnover, including root herbivory of the soil fauna.
Methods: Modern techniques of rhizosphere research shall be applied including rhizoscopes, ingrowth cores, 14C-AMS-dating and 15N labelling.
B3: Rainfall partitioning and soil water dynamics in forest stands of different tree species diversity Project leader: Prof. Dr. Dirk Hölscher, Burckhardt Institute, Section of Tropical Silviculture and Forest Ecology, Büsgenweg 1, 37077 Göttingen, Germany; E-mail: dhoelsc@gwdg.de
Aims of the project: To identify mechanisms determining the role of tree species diversity in the forest hydrological cycle. Methods: Measurement of rainfall, throughfall, and soil moisture in the field. Main focus is on data analysis and will include integrative approaches, statistics, and model applications.
B4: Complementarity of water use between 5 tree species in species-rich deciduous forests. Project leader: Prof. Dr. Christoph Leuschner, Plant Ecology, University of Göttingen, Untere Karspüle 2, 37073 Göttingen; E-mail: cleusch@gwdg.de; Dr. Stefan Fleck, sfleck@gwdg.de.
Aims of the project: Species-specific characterization of transpiration and stomatal conductance in relation to climate parameters. Mechanistic analysis of water consumption in tree clusters of variable composition. Methods: Measurement of water flux in tree canopies using a mobile canopy lift. Xylem sap flow measurements and porometry in the canopy. Characterization of cavitation vulnerability. Up-scaling of complementarity effects to the forest stand.
B5: Effects of nutrient cycling through litter of deciduous tree species on soil biochemical properties and the dynamics of C and N in soil.
Project leader: Prof. Dr. Heiner Flessa, Soil Science of Temperate and Boreal Ecosystems, Büsgen Institute, Büsgenweg 2, 37077 Göttingen; E-Mail: hflessa@gwdg.de
Aims of the project: To assess the role of tree litter composition for nutrient availability in soils, neutralisation of soil acidity and the transformation and translocation of carbon and nitrogen in soils.
Methods: Characterization of acidity and nutrient availability in forest soils, determination of the C and N mineralization and immobilization in soils, field experiments in the Hainich National Park, soil incubation studies with 15N labelled tree litter.
B6: Compound specific isotope ratios to trace element flow in diversity clusters.
Project leader: PD Dr. Gerd Gleixner and Prof. Dr. E. Detlef Schulze, Max Planck Institute for Biogeochemistry, Box 100164, 07701 Jena; E-mail: gerd.gleixner@bgc-jena.mpg.de

Aims of the project: To understand the effect of diversity on the element flow in ecosystems. In the project chemical and isotopic signals of individual molecules isolated from various ecosystem compartments will be analysed in order to follow the flow of applied label at ecosystem interfaces like root/microorganisms, leaf/atmosphere or mineral surfaces/soil organic matter. Methods: Compound specific isotope measurements (GC or LC), GC/MS or LC/MS.
Prerequsites: Chemical background of the candidate is beneficial but not mandatory. Close cooperation to other graduates as a joint research team is necessary.
C1: 3D-light-modelling for tree clusters based on automated structure detection by 3D-laserscanner measurements. Project leader: Dr. Stefan Fleck and Prof. Dr. Christoph Leuschner, Plant Ecology, University of Göttingen, Untere Karspüle 2, 37073 Göttingen; E-mail: cleusch@gwdg.de, sfleck@gwdg.de
Aims of the project:
Measurement and Representation of differences in 3D-canopy structure based on automated structure measurements. Using 3D-point clouds for parameterization of a 3D-light model. Simulation of hemispherical photographs at defined positions in the canopy. Comparing light and wind-effects as drivers of shoot growth and competition.
Methods: 3D-laser-scanning, validation measurements using a mobile canopy lift, 3D-data extraction and light modelling
C2:Economic valuation of functional biodiversity and ecosystem services including insurance services
Project leaders: Prof. Dr. Rainer Marggraf & Dr. Jan Barkmann, Department of Agricultural Economics and Rural Development, Environmental & Resource Economics, Platz der Göttinger Sieben 5, D-37073 Göttingen (Germany); E-mail: rmarggr@gwdg.de
The following potential research topics of the project will be approached with a choice experiment that represents an extension of the choice experiment methodology of the previous phase (attributes: e.g., CO2 sequestration services, environmental disaster protection): Mental budgeting of stated preference responses on biodiversity protection; comparison of WTP for personal (financial) insurance versus biodiversity as ecological insurance against environmental risks; influence of existence and bequest value motivations or of perceived response efficacy on WTP; influence of previous knowledge on stated preferences for biodiversity and ecosystem services.
C3:Modelling carbon and nutrient turnover of different tree species within mixed stands. Project leader: Prof. Dr. F. Beese, Büsgen Institute, Soil Science of Temperate and Boreal Ecosystems, Büsgenweg 2, D-37077 Göttingen; E-mail: fbeese@gwdg.de and PD E. Priesack, Helmholtz Center München, Institute of Soil Ecology, Ingolstädter Landstr.1, D-85764 Neuherberg, E-mail: priesack@helmholtz-muenchen.de
Aims of the project: Modelling of C- and N-turnover of single tree species within mixed stands. Methods: Measurement of model variables including the use of stable isotopes of C, N, O and H and the determination of tree architectures. Adaptation of single tree models to the specific conditions of the sites. Validation of model results.

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