Leibniz Institute for Tropospheric Research (TROPOS), Leipzig

The Leibniz Institute for Tropospheric Research (TROPOS) is an internationally renowned research institute in the field of aerosol and cloud research, and a member of the Leibniz Association. The department of Atmospheric Chemistry (ACD) and Atmospheric Microphysics (AMP) research the chemical and physical properties of aerosol particles and their interactions with clouds. Process-based laboratory studies and long-term observations contribute significantly to the understanding of climate change and its effects.

A central aspect of cloud and climate research is the investigation of the ability of mixed-phase clouds to form precipitation. This depends largely on the presence of ice crystals. In a preliminary study, we were able to show that long-chain carbohydrates (polysaccharides) produced by microorganisms catalyze the freezing of cloud droplets. These substances are a significant source of so-called ice-nucleating particles, particularly over remote marine regions.

The aim of the advertised PhD position is to investigate the influence of these polysaccharides on ice formation in clouds in detail and make it quantifiable. To this end, existing chromatographic analysis methods are to be further developed in order to improve the chemical characterization of these ice-active compounds. The optimized analysis techniques will then be applied to a selection of atmospheric aerosol, cloud and precipitation samples of both marine and terrestrial origin. Samples will be collected in at least one field campaign during the course of the PhD, with a particular focus on terrestrial environments, which are characterized by different biological source mechanisms than marine systems.

The project will improve our understanding of the interactions between the biosphere and the atmosphere. In the long term, it contributes to the improvement of climate prediction models.

The Atmospheric Chemistry and Atmospheric Microphysics departments are looking for a committed doctoral student to carry out this project. You can expect an exciting research activity at a non-university, internationally networked institute with a dynamic and interdisciplinary working environment.

Your tasks:

• Further development of existing methods for carbohydrate analysis using ion chromatography (e.g. HPIC, HPAEC-PAD, LC-MS) and preparative column chromatography
• Planning and carrying out sampling as part of field campaigns
• Independent performance, evaluation and interpretation of chemical laboratory analyses and microphysical freezing experiments
• Presentation of results at international conferences
• Preparation of a cumulative dissertation with two to three publications of the scientific results in renowned, peer-reviewed journals is aimed for
• Collaboration with national and international project partners

Your profile:

• Successfully completed Master's degree in chemistry, food chemistry, biochemistry, physics, meteorology or a comparable natural science discipline
• High level of motivation, initiative and interest in interdisciplinary research
• Solid lab experience and enthusiasm for experimental work
• Basic knowledge of instrumental and preparative chromatography
• Fluent in written and spoken English
• Confident handling of common analytical software (e.g. Excel, Origin, R, Python)
• Driving licence (class B) is desirable

The position will be filled by 1 October 2025 at the earliest.

We offer an exciting position with varied activities in an interdisciplinary working environment and a variety of measures to reconcile work and family life as well as flexible working hours and daycare places. The employment is limited to 36 months (75% TV-L 13) including the attractive social benefits of the public sector. In order to increase the proportion of female employees in scientific and science-related positions, we hereby expressly invite female applicants to apply. Severely disabled persons (according to the Ninth Book of the German Social Code) will be given preference if they have the same aptitude, skills and professional qualifications.

If you are interested, please send your complete and informative application documents (including references and a letter of motivation) by 14 August 2025 exclusively by e-mail in one coherent PDF document to:

application(at)tropos.de; subject: "ice-nucleating polysaccharides" (ACD, AMP)

If you have any questions about this vacancy, please contact:

Dr. Sebastian Zeppenfeld, zeppenfeld(at)tropos.de, +49(0)341-2717-7360

Dr. Susan Hartmann, susan.hartmann(at)tropos.de, +49(0)341-2717-7489

By sending the application documents by e-mail, the applicant agrees to the storage/processing of personal data in accordance with Art. 13 DSGVO for the purpose of selection for this job advertisement. Attention is hereby drawn to the risks involved in sending documents electronically.

Further information on TROPOS and the doctoral program can be found on the homepage: www.tropos.de and in the following publications.

Zeppenfeld, S. et al. Marine carbohydrates in Arctic aerosol particles and fog – diversity of oceanic sources and atmospheric transformations. Atmospheric Chemistry and Physics23, 15561–15587 (2023), doi.org/10.5194/egusphere-2023-1607.

Hartmann, S. et al. Polysaccharides─Important Constituents of Ice-Nucleating Particles of Marine Origin. Environ. Sci. Technol.59, 5098–5108 (2025), https://doi.org/10.1021/acs.est.4c08014.