Microbial dormancy in Glacier Microbial Communities: Environmental Controls and Kinetics
Master 2 internship – Academic year 2026 – 2027
Supervisors: James A. BRADLEY (james.bradley@mio.osupytheas.fr) and Lasse Z. JENSEN (Lasse.z.jensen@gmail.com)
Team: Environmental Microbiology and Bioprocesses (MEB), Mediterranean Institute of Oceanography. Aix-Marseille University.
Websites:
Expected start date: January 2027 (flexible)
Contract period: 6-9 months (with stipend/gratification), possibly longer.
Workplace: Mediterranean Institute of Oceanography, Luminy Campus, Marseille, France
Type of contract: Internship convention
Proportion of work: Full time
ABSTRACT:
Dormancy is one of the key adaptive strategies employed by microorganisms to withstand unfavourable environmental changes [1]. Microbial activity can be represented by a continuum of physiological states, ranging from growth and cell division to strongly reduced metabolic activity and dormancy [2]. These state transitions may play an important role in structuring microbial communities, maintaining ecosystem resilience, and regulating biogeochemical processes [3]. Cryospheric ecosystems provide ideal natural settings to investigate microbial activity and dormancy because they experience strong environmental gradients in temperature, nutrient availability, liquid water, and light exposure [4,5]. As the Arctic warms rapidly [6] and polar glacier environments become more variable, changes in temperature, meltwater availability, nutrient inputs, and light exposure may alter the balance between active and dormant microbial cells.
AIM: The objective of the Master’s project is to determine how rapidly dormant or inactive glacier microbial communities resuscitate following thawing, and how this response is influenced by key environmental conditions.
The student will perform controlled laboratory experiments using cryoconite samples, focusing on the transitioning from frozen to thawed conditions. Experiments will be designed to test how temperature and resource availability influence the kinetics and extent of microbial resuscitation over time. Microbial responses will primarily be assessed using single-cell activity markers such as RedoxSensor Green (RSG) together with measurements of total cell abundance. By following the microbial communities over multiple time points after thawing, the student will quantify parameters such as the active fraction, activation lag, rate of resuscitation and the proportion of cells remaining inactive or dormant. These experiments will help to determine whether environmental conditions primarily control how rapidly glacier microorganisms reactivate and how many cells recover activity.
The results will contribute to understanding how dormancy and resuscitation allow glacier microbial communities to respond to rapidly changing environmental conditions and persist through periods of freezing and resource limitation.
Work context:
- You will work on a cutting-edge topic in cryospheric microbial ecology and global environmental change.
- You will join a large international multidisciplinary team of microbiologists, biogeochemists, and Earth system scientists.
- You will receive a stipend in accordance with current regulations.
Eligibility Criteria:
The candidate must have validated a first year of Master studies in a relevant natural science discipline (e.g. microbiology, biology, ecology).
Required skills:
The student must have a working knowledge of microbial ecology, biogeochemistry, and/or cellular processes. The student must have basic knowledge of microbiology lab practices, including sterile techniques and basic microscopy. Experience with microbial viability or activity staining, fluorescence microscopy, or flow cytometry is an advantage. The candidate should be proactive and capable of working independently, as well as working harmoniously as part of a team. The working language is English and thus fluency in the English language is required.
How to apply:
Please send your CV and cover letter IN ENGLISH to James Bradley (james.bradley@mio.osupytheas.fr) and Lasse Z. JENSEN (Lasse.z.jensen@gmail.com). The cover letter, maximum 2 pages, should state your motivation for applying to this position, research interests, relevant skills, training, and experience. Please send your application materials as soon as possible, and preferably before 15 October 2026. Applications will be evaluated in the order that they are received.
References:
[1] Lennon, J. T. & Jones, S. E. Microbial seed banks: the ecological and evolutionary implications of dormancy. Nat. Rev. Microbiol. 9, 119–130 (2011).
[2] Guigard, L. et al. From dividing to dormant: embracing the full activity spectrum for environmental microorganisms. Microbiol. Mol. Biol. Rev. e00354-25 (2026).
[3] Bradley, J. A. Microbial dormancy as an ecological and biogeochemical regulator on Earth. Nat. Commun. 16, 3909 (2025).
[4] Bradley, J. A. et al. Active and dormant microorganisms on glacier surfaces. Geobiology 21, 244–261 (2023).
[5] Anesio, A. M., Lutz, S., Chrismas, N. A. M. & Benning, L. G. The microbiome of glaciers and ice sheets. npj Biofilms Microbiomes 3, 10 (2017).
[6] Rantanen, M. et al. The Arctic has warmed nearly four times faster than the globe since 1979. Commun. Earth Environ. 3, 168 (2022).
Requirements
Research Field: Biological sciences » Other
Education Level: Bachelor Degree or equivalent
Skills/Qualifications
The student must have a working knowledge of microbial ecology, biogeochemistry, and/or cellular processes. The student must have basic knowledge of microbiology lab practices, including sterile techniques and basic microscopy. Experience with microbial viability or activity staining, fluorescence microscopy, or flow cytometry is an advantage. The candidate should be proactive and capable of working independently, as well as working harmoniously as part of a team. The working language is English and thus fluency in the English language is required.
Specific Requirements
Please send your CV and cover letter IN ENGLISH to James Bradley (james.bradley@mio.osupytheas.fr) and Lasse Z. JENSEN (Lasse.z.jensen@gmail.com). The cover letter, maximum 2 pages, should state your motivation for applying to this position, research interests, relevant skills, training, and experience. Please send your application materials as soon as possible, and preferably before 15 October 2026. Applications will be evaluated in the order that they are received.
Languages: ENGLISH
Level: Excellent
Additional Information
Eligibility criteria
The candidate must have validated a first year of Master studies in a relevant natural science discipline (e.g. microbiology, biology, ecology).
Website for additional job details: https://www.jbradleylab.com/
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