An increasing number of scientists and disciplines around the world are benefitting from the application of stable water isotope techniques (2H and 18O), especially in ecohydrology. Stable isotope analysis of environmental waters can help to investigate water flow paths through the Earth’s critical zone. However, clear bottlenecks for the ubiquitous application of isotopic analysis are the relatively high-energy and specialized systems required to collect and extract water vapor from plants. Could a simple and cost-effective chamber system be sufficient for collection water vapor for isotopic analysis from trees’ bark and leaves? And is the isotopic signature measured with this new chamber comparable to state of the art methods?

In this study, we would like to develop and evaluate a chamber system for measuring the isotopic composition of evaporated and transpired plant waters. The basic concept is to collect transpired vapor from leaves and evaporated water vapor from trees’ bark in a gas-tight chamber that can subsequently be analyzed with an isotope analyzer. The system will be tested under lab and field conditions and adapted to different tree species. Figure 1 shows a prototype of a chamber system for measuring the transpiration isotopic composition.

Fig. 1: Prototype of a chamber for measuring the transpiration isotopic composition

Against this background, the potential candidate would:

• Develop and test a chamber system (access to a 3D-printer)
• Prepare and conduct lab and field tests
• Sample evaporated and transpired water vapor for isotope analysis
• Determine isotopic differences between species’ evaporated and transpired water vapor
• Analyze and interpret the isotope data

The student/s should be interested in conducting field and lab work and enjoy hands-on work in the workshop (McGyver-type candidates are ideal for this MSc). Among others the candidate will have access to a 3D printer to produce custom-made parts for the chamber prototype. The student should also be familiar with statistical software, such as R or Python.

Natalie Orlowski: natalie.orlowski@hydrology.uni-freiburg.de; Tel. 0761 - 203-9283 Stefan Seeger: stefan.seeger@hydrology.uni-freiburg.de; Tel. 0761 – 203-9290

Englisch/Deutsch