One internship position focusing on the vulnerability of freshwater species to climate change in relation to their trophic position is available at the RECOVER laboratory in Aix-en-Provence (France). The student will work under the supervision of Arnaud SENTIS, Antoine PERRICHER, Alexandra ENGLER, and Nathalie REYNAUD.
Topic:
Climate change and extreme climatic events such as heatwaves are expected to strongly impact the structure and functioning of freshwater ecosystems. While numerous studies have investigated species’ thermal tolerance, we still lack a clear understanding of how vulnerability to heatwaves depends on species’ trophic position within ecological networks. Top predators may be more vulnerable due to their large body size, low abundance, and strong dependence on lower trophic levels, or conversely more resistant due to their ecological flexibility and mobility.
Objective:
The aim of this internship is to assess whether species at the top of freshwater food webs (e.g., fish) are more or less vulnerable to heatwaves compared to species at lower trophic levels (e.g., phytoplankton, zooplankton, macroinvertebrates).
The intern will:
• Use an existing database of lakes containing information on phytoplankton, zooplankton, macroinvertebrates, and fish communities,
• Compile data on species’ upper thermal limits (CTmax),
• Reconstruct trophic networks for these communities,
• Quantify species’ vulnerability to heatwaves according to their trophic position and body size.
Methods and data:
The project will combine database analyses, literature review for species’ CTmax, food web reconstruction, and statistical analyses of species vulnerability across trophic levels. Depending on the student’s interests and background, additional analyses could include body size scaling or comparisons across lakes.
Candidate competences:
We are seeking a motivated student with a strong interest in ecology, climate change biology, and biodiversity research. Skills in ecological data analysis, statistics (R), and food web ecology are desirable. Previous experience with literature reviews and database management would be appreciated.
Practical information:
Starting date (flexible): February 2026
Duration: 6 months
Location: INRAE, RECOVER laboratory, 3275 route Cézanne, 13182 Aix-en-Provence, France
Main advisors: Arnaud Sentis, Antoine Perricher, Alexandra Engler, Nathalie Reynaud
Application:
Deadline for applications: November 11, 2025.
Please send your CV and a motivation letter (1 page maximum, in French or English) to:
– arnaud.sentis@inrae.fr
– antoine.perricher@inrae.fr
– alexandra.engler@inrae.fr
– nathalie.reynaud@inrae.fr
Informal enquiries are welcome – please contact us by email in French or English.
Key-words:
climate change, heatwaves, thermal tolerance, food webs, trophic ecology, freshwater lakes
References:
Bayat, H.S., He, F., Medina Madariaga, G., Escobar-Sierra, C., Prati, S., Peters, K. et al. (2025). Global thermal tolerance compilation for freshwater invertebrates and fish. Scientific Data, 12, 1488.
Peralta-Maraver, I. & Rezende, E.L. (2021). Heat tolerance in ectotherms scales predictably with body size. Nat. Clim. Change, 11, 58-63.
Dahlke, F.T., Wohlrab, S., Butzin, M. & Pörtner, H.-O. (2020). Thermal bottlenecks in the life cycle define climate vulnerability of fish. Science, 369, 65-70.
Desforges, J.E., Birnie‐Gauvin, K., Jutfelt, F., Gilmour, K.M., Eliason, E.J., Dressler, T.L. et al. (2023). The ecological relevance of critical thermal maxima methodology for fishes. J. Fish Biol., 102, 1000-1016.
Jørgensen, L.B., Ørsted, M., Malte, H., Wang, T. & Overgaard, J. (2022). Extreme escalation of heat failure rates in ectotherms with global warming. Nature, 611, 93-98.
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