open positions

Bachelor and Master Theses

1. Phosphate concentrations in beech tree tissues affected by N-fertilization
2. The effect of N-fertilization on phosphate concentrations in tissues of transgenic Populus x canescens.

The chair of ecosystem physiology offers the possibility to participate in the interdisciplinary priority program SPP 1685 - Ecosystem nutrition: forest strategies for limited phosphorus resources (http://www.ecosystem-nutrition.uni-freiburg.de/) in the frame of bachelor or master theses. Phosphorus (P) is an essential nutrient for plant growth and development that is often limited in forest ecosystems. The P-nutrition of beech forests is a highly regulated process that involves complex interactions between ecosystem processes such as P-release from bedrock, allocation processes in soil, microbial turnover and P-acquisition by trees. Highly productive ecosystems have been developed, which in case of P-limitation are shaped towards efficient internal nutrient cycling systems. This is especially emphasize because the productivity of beech (Fagus sylvatica) trees along a natural geosequence with decreasing soil-P availability is comparable. Beech trees P requirements for growth and biomass production are achieved by a highly effective internal P-cycling strategy that is controlled by seasons and could be intensified in case of P-limitation. In contrast to beech, the fast growing grey poplar (Populus x canescens) naturally establishing at high soil-P sites meet their P-demand by P-acquisition from the soil and not by seasonal controlled P-storage and P-mobilization. Obviously, poplar trees adapted their P-nutrition strategy to the natural growth habitat of floodplains with generally high soil-P. It seems that the P-nutrition of trees depends on the ecological niche and/or the natural ecosystem. The priority program `SPP 1685 - Ecosystem nutrition: forest strategies for limited phosphorus resources´ made large progress in understanding P-nutrition of beech forests. However, it remained largely unknown in which way anthropogenic activities can influence the beech ecosystems. Atmospheric N-deposition gets increased over the last decades and is manifested in increasing N:P ratios of beech leaves all over Europe. Hence, the increase in N by atmospheric deposition may provoke P-limitation. The currently running project investigated the influence of N-deposition on P-nutrition that is simulated by increasing N-fertilization for poplar and beech under controlled conditions and in the field.

What we expect:      

• Motivated and responsible work in a biochemical laboratory
• Reading of publications written in English
• Presentation of results in English

What we offer:        

• Participation in an interdisciplinary research program
• Work in a developing field of ecosystem research
• Support and supervision during lab work, data analyses, and writing
• Integration of a possible candidate in a newly formed working group
• Thesis can be written in English and German
• Co-author ship on potential publications

Contact: If you are interested in a Master or Bachelor thesis please contact:

   Prof. Dr. Cornelia Herschbach: cornelia.herschbach@ctp.uni-freiburg.de or

   Florian Netzer: florian.netzer@ctp.uni-freiburg.de

Chair for Ecosystem Physiology,

Institute for Forest Sciences,

Albert-Ludwigs-University Freiburg,

Georges-Köhler-Allee 53/54.