One year postdoc position in Atmospheric Chemistry, Marine Microbiology (funded by Amidex)

The SARNEIO project is funded by the Institute Ocean (AMIDEX, AMU) and LEFE VACOA (CNRS) grants and will be held in Marseille, France.

Volatile organic compounds (VOCs) emitted by communities of microorganisms are called the "volatilome" and play an ecological role as chemical mediators. They are also key atmospheric components, affecting health through the formation of secondary pollutants (including ozone and fine particles), as well as climate by modifying cloud properties, one of the greatest uncertainties in climate projections.

Although their atmospheric impact is widely recognized, the plankton volatilome is not well characterized in marine environments. Moreover, VOC emissions related to the metabolism of many plankton species remain unidentified, leading to uncertainties in estimating marine VOC emissions and, consequently, air-sea exchanges. In the context of global warming, it is crucial to characterize VOC fluxes from the oceans, as well as the parameters that govern these emissions.

The SARNEIO project aims to fill this knowledge gap by characterizing the phytoplankton volatilome in relation to community composition and spatiotemporal distribution, quantifying VOC concentrations and emissions within sea water. To achieve this goal, the project will (1) develop a unique experimental setup combining measurements of VOC concentrations and phytoplankton abundances, (2) assess the volatilome across identified phytoplankton cultures, (3) investigate the relationship between VOC concentrations and plankton diversity in natural seawater using the new setup.

The recruited individual will be responsible for building a dynamic sampling system to analyze VOCs in water, then evaluating this device using a PTR-ToF-MS. This new experimental setup will then be coupled with a Cytosense flow cytometer. The candidate will be responsible for deploying this innovative device, initially in the laboratory using dynamic chambers in which plankton cultures will be placed. If experimental development is sufficiently advanced, the device will then be deployed at the Endoume marine station by the recruited individual for initial measurements in the natural environment.

In addition to the experimental component described above, the candidate will be responsible for all data analysis and data processing.

The project and the developed instrumental setup aim to significantly advance our understanding of VOC concentrations and fluxes and their environmental determinants, allowing for the assessment of the role of plankton in VOC emissions within the marine ecosystem. This knowledge is essential for a better understanding of the involvement of plankton in VOC emissions and, by extension, in the dynamics of the marine ecosystem. In addition, the VOC flux datasets provide quantitative insight into the exchange of reactive trace gases between seawater and the atmosphere, elucidating the relationships between VOC fluxes and environmental variables. These datasets are of great value to modelers, as they allow parameterization of VOC concentrations in water as a function of phytoplankton abundance and improve climate predictions.

TYPE OF CONTRACT: TEMPORARY

JOB STATUS: FULL TIME

HOURS PER WEEK: 35

APPLICATION DEADLINE: 15/09/2025 23H59

ENVISAGED STARTING DATE: 02/01/2026

ENVISAGED DURATION: 12

WORK LOCATION(S): UMR MIO Marseille

WHAT WE OFFER: The candidate will be recruited at the MIO and will benefit from a reception office for the duration of their contract, and will carry out a significant part of the experimental development at the LCE. The candidate will be under the supervision of M. Thyssen (MIO) and J. Kammer (LCE), and will benefit from the support of the technical teams of both laboratories. The candidate will have access to the LCE's cutting-edge MASSALYA platform for VOC measurements, and to the SSL@MM research laboratory at the Endoume Marine Station. Salary between €2616.35 and €3062.56 gross per month depending on experience.

Additional information: The Euraxess Center of Aix-Marseille University informs foreign visiting professors, researchers, postdoc and PhD candidates about the administrative steps to be undertaken prior to arrival at AMU and the various practical formalities to be completed once in France: visas and entry requirements, insurance, help finding accommodation, support in opening a bank account, etc. More information on AMU EURAXESS Portal.

QUALIFICATIONS, REQUIRED RESEARCH FIELDS, REQUIRED EDUCATION LEVEL, PROFESSIONAL SKILLS, OTHER RESEARCH REQUIREMENTS: The candidate must hold at least a PhD in environmental sciences (ideally in atmospheric chemistry) and have a 3 years’ experience in research. He/She will have interest in, or have conducted research in, oceanography. Strong knowledge of experimental VOC measurements using PTR-MS and flow cytometry is required for this position with experience in both technics. Given the short-term nature of the project, the training period is not compatible with scientific development. The candidate must also enjoy both field and laboratory work (for chemical analyses), and must demonstrate experience in developing complex experimental setups. They must have a strong understanding of time series statistics and automated data processing (preferably proficiency in the R programming language) due to the large amount of data that will be generated.

Soft skills: As the project is interdisciplinary, the candidate must be motivated and ensure that complementary areas of expertise are integrated in a balanced manner, regularly present their progress to the team and write scientific articles in English, demonstrate organization, listening skills, dynamism and communication skills and have a minimum B2 level of English. Experimental fieldwork requires being able to adapt and modify campaign dates according to unforeseen circumstances (weather conditions, instrument failure, etc.). The candidate must be flexible and available.

REQUESTED DOCUMENTS OF APPLICATION, ELIGIBILITY CRITERIA, SELECTION PROCESS: Curriculum vitae

HOW TO APPLY: melilotus.thyssen@mio.osupytheas.fr, Julien.kammer@univ-amu.fr, sarah.thomas@univ-amu.fr