PhD Student (36 months, 65%):
Ecohydrological connectivity between trees and the capillary zone.

Isodrones ( is a research group located at the Institute for Geoecology, Technical University Braunschweig. The group is dedicated to developing novel and innovative methods to investigate different aspects of the water cycle.

The DFG funded project "CONFOR: Ecohydrological connectivity between trees and the capillary zone - a key driver for drought resilience of European forests?" aims to quantify spatiotemporal dynamics and feedbacks between precipitation and capillary rise from groundwater replenishing the capillary zone as well the interaction of typical European forest trees with distinct water-use strategies and rooting depth with the deep soil water pools. Within the project, we want to address the following questions: How important is the deep unsaturated zone and capillary fringe for the water supply of different European tree species? How does this change with the season and topography? Which implications for groundwater recharge generation do different tree species have?

We aim to use a combination of ecohydrological, plant physiological, UAV-based, geophysical, and model-based approaches on our central observational site in Apelern, near Hanover. This is one of two PhD positions to be filled within the project. For the advertised PhD-project, the selected candidate will apply in situ water stable isotope methods in soils and trees in order to investigate dynamic water uptake depths and amounts of different tree species. The PhD candidate will be responsible for establishing a monitoring network for soil moisture, groundwater level and water isotopes in trees and soils along a hillslope at our core site in the Weserbergland, Lower Saxony. In summer of 2023 and 2024, a large deep soil labelling experiment will be carried out and the fate of the water through the water cycle will be traced. The collected data will be used to parameterize an isotope-enabled soil-plant-atmosphere model and carry out scenario analysis in order to predict changes of groundwater levels and recharge on forest health.


We are looking for a motivated and open-minded candidate who is committed in understanding the role of trees in the water cycle and how forests interact with the atmosphere and soils. The candidate must have an interest in field research and ecohydrological questions, as well as an interest in water stable isotope methods for investigating water uptake.


  • establishment of a monitoring network
  • independent analysis of continuously recorded variables (e.g., soil moisture, water potential, groundwater level)
  • apply and improve in situ monitoring techniques for water stable isotopes of trees and soils
  • conceptualization and implementation of a deep soil labelling experiment using deuterated water
  • determination of soil hydraulic properties and root biomass
  • laboratory analysis of soil and plant samples for water isotope analysis
  • close collaboration with the other PhD students and members of the project and working group
  • presentation of research results at national/international conferences
  • publication of results in peer-reviewed scientific journals


This position is available as a PhD position. The minimum requirements are:

  • University degree (Univ.-Diplom or M.Sc.) in the field of geoecology, hydrology, forestry, environmental, soil science or related subjects
  • profound knowledge in ecohydrology, hydrology and soil water movement
  • knowledge of forest ecosystems are beneficial
  • willingness to conduct physically demanding field work during field trips over several days
  • team spirit, flexibility, high motivation and the ability to work independently
  • scientific curiosity and willingness to work on a doctoral thesis
  • excellent communication and writing skills in English

This is a 65% PhD position, limited to 3 years. The salary will be paid in accordance with the Collective Agreement for the Public Service (Tarifvertrag für den öffentlichen Dienst der Länder, TV-L13). The place of employment will be Braunschweig. Equal opportunities are an integral part of our personnel policy. The TU Braunschweig aims to achieve balanced employment and therefore strongly encourages qualified candidates from all societal groups to apply. Women are particularly encouraged to apply. Applicants with disabilities will be given preference when qualifications are equal.

The application should include the following information: CV, transcript of records, certificates, letter of motivation. Please submit your application by December 31st 2022 as one pdf file to Dr. Matthias Beyer, research group leader of Isodrones;

If you have any questions, please do not hesitate to contact us: Dr. Matthias Beyer, phone +49(0) 531 391-5913, Email:

posted: 29 November 2022     Please mention EARTHWORKS when responding to this advertisement.