100% / Expected start date is 1 June 2021 or later
The Aquatic and Isotope Biogeochemistry Research Group at the Department of Environmental Sciences, University of Basel (https://duw.unibas.ch/de/bgc/) invites applications for a PhD position in the field of nitrogen isotope biogeochemistry and paleolimnology. The student will be part of a project investigating the validity of the diatom nitrogen isotope paleo-proxy in the marine and lacustrine environments through a combination of experimental and field studies. Research is planned in collaboration with scientists from Umea University, Sweden (Department of Ecology and Environmental Sciences) and the Max Planck Institute for Chemistry, Germany (Climate Geochemistry Department).
The analysis of the nitrogen (N) isotope composition of fossil shells (such as diatoms) is a powerful tool to study the aquatic N cycle of the past, but a thorough ground-truthing of the diatom N isotope proxy is still lacking. This PhD project aims to investigate whether the N isotope composition of diatom shell-bound ("diatom-bound") N is altered during diagenesis in the water column or in the sediment over time. Towards this goal, the PhD student will perform degradation experiments of diatom culture material under oxic and anoxic conditions for subsequent N isotope analysis. Furthermore, from a lake in Sweden, the PhD student will measure and compare the diatom-bound N isotope composition of sediment trap, sediment surface and downcore sediment material through time. Finally, the PhD student will test the applicability of the diatom N isotope proxy to Swiss lake sediments to reconstruct the eutrophication history over the past century. The project involves extensive laboratory work with a focus on N isotope analyses. At the same time, the PhD student will also have the opportunity to join fieldtrips to Swiss lakes to collect sediment cores. The overall goal of this project is to improve our understanding of the preservation of the diatom-bound N isotope signature after shell formation, which will contribute to validate the diatom N isotope proxy as a tool for paleoclimate reconstructions in both the marine and lacustrine environments.
We are looking for a highly motivated candidate with a master's degree in geosciences, environmental sciences, chemistry, biology or a related discipline. Candidates are expected to have a solid background and interest in (paleo-)limnology, oceanography, and biogeochemistry in aquatic systems in general. Expertise in stable nitrogen isotope/mass-spectrometric techniques will be an advantage. Clean and precise work in the laboratory are a must. The ability to work both independently and within a team, as well as good communication skills including fluency in English are essential.
We offer you
The PhD project (100%) will be part of a research project funded for 4 years by the Swiss National Science Foundation. We offer an international, multidisciplinary work environment and excellent research infrastructure. Compensation will be according to the guidelines of the Swiss National Science Foundation (www.snf.ch).