Research Assistant; Doctoral Researcher; f​/m​/d research project

Research Assistant (Doctoral Researcher) (f/m/d)
for the research project “Phytoplankton microbiomes”

Classifications E 13 -
part-time 65%
Reference number: A024-26
Closing date: 03/19/2026
Public vacancy

The University of Bremen - Faculty 2 - (Biology/Chemistry) is offering a fixed-term position as soon as possible for a

Research Assistant (Doctoral Researcher) (f/m/d)
Salary Scale 13 TV-L
with 65% of the regular weekly working hours (25.48 hours/week)
for a fixed term of 36 months (according to § 2 (2) WissZeitVG )

We are looking for highly motivated candidates for the research project “Phytoplankton microbiomes: A trait for adaptation and poleward range shifts?”, funded by the German Research Foundation (DFG). This project combines the expertise of the University of Bremen, the Alfred‑Wegener‑Institute, Helmholtz Centre for Polar and Marine Research, and GEOMAR, Helmholtz Centre for Ocean Research.

In the different Southern Ocean (SO) regions, phytoplankton encounter distinct environmental regimes, requiring effective adaptation mechanisms. We hypothesize the functional differentiation and adaptation of phytoplankton microbiomes to be an important driver enabling ecotypic differentiation of diatoms in SO regions. Therefore, we aim to characterize phytoplankton trait‑based abilities from a microbiome perspective and explore the microbiome’s functional potential to foster coping strategies and adaptation of phytoplankton to challenging Antarctic conditions.

By combining laboratory experiments mimicking Antarctic environmental regimes to monitor the joint response of the phytoplankton host and its microbiome and analyzing Antarctic field samples, you will investigate how microbiome bacteria contribute to phytoplankton fitness. You will cultivate microalgae, and analyze the microbiome community dynamics via (single-host-cell) amplicon sequencing, analyze the functional repertoire of the microbiome via metagenomic sequencing and meta genome‑assembled‑genome (MAG) construction, and decipher the phytoplankton host’s response through RNA sequencing.

Your project will be under the direction of Prof. Tilmann Harder (Marine Chemistry) and is related to a microbiological Post Doc project (Dr. Jakob Giesler). You will have the opportunity to work on your PhD in a small research group and will be supported by the Research Academy  will also be able to collaborate with national and international research partners.

Your responsibilities:

• Cultivation of marine microalgae and bacteria
• Conducting controlled growth experiments under laboratory conditions
• Preparation and analysis of molecular samples for amplicon sequencing, metagenomic sequencing, and RNA sequencing
• Molecular analysis of field samples (single cells and bulk DNA/RNA)
• Scientific publishing
• The position offers the opportunity for academic qualification

• Completed scientific university degree (Master's/University Diploma) in (marine) biology, microbiology or a related field. Applicants who are in the final phase of their Master's degree will also be considered. Please note that submission of the Master's degree certificate is mandatory for employment.
• Experience in analyzing microbial metagenomic data
• Great basic research interest in microbial ecology, phytoplankton ecology, and polar microbiology
• High motivation and above‑average qualification to work actively in an interdisciplinary research and education environment
• Independent working style with hands‑on mentality, team spirit, helpfulness, and reliability

Open to unconventional approaches in research and teaching, the University of Bremen has retained its character as a place of short distances for people and ideas since its founding in 1971. With a broad spectrum of subjects, we combine exceptional performance and innovative potential. As an ambitious research university, we stand for research‑based learning approaches and a pronounced interdisciplinary orientation. We actively pursue scientific cooperation in a spirit of global partnership.

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