An internship position focusing on the role of prey diversity in freshwater predator-prey systems for buffering the impacts of heatwaves is available at the RECOVER laboratory of the INRAE in Aix-en-Provence (France). The student will work under the supervision of Tom REVEILLON (postdoctoral researcher, INRAE UMR RECOVER) and Arnaud SENTIS (research director, INRAE UMR RECOVER).
Context
Global warming is impacting biodiversity across all levels of biological organization, from individual physiology to population dynamics and ecosystem processes (Walther et al. 2002). At the individual level, temperature affects fundamental physiological rates (Brown et al. 2004) and energetic balance (Réveillon et al. 2022). Organisms may become energetically imbalanced, with consequences for growth survival and reproduction. These effects can scale up to influence population and community dynamics (Woodward et al. 2010).
Biodiversity can buffer organisms and ecosystems against environmental disturbances (Loreau et al. 2021). In predator-prey systems, prey diversity may provide an additional, yet overlooked, form of buffering by supplying predators with diverse nutritional resources (hereafter: prey energetic diversity). Prey can differ strongly in their elemental composition, particularly in carbon, nitrogen and phosphorus, thereby influencing the nutritional and energetic balance of their predators.
This resource-based dimension of biodiversity may be particularly important under warming. Temperature can increase predator energy requirements while altering the nutritional composition of their prey (Elser et al. 2000). Predators facing warming may therefore experience increasing constraints on the acquisition of the energy and nutrients required for persistence (Diehl et al. 2022). They may therefore benefit not only from abundant prey, but also from prey assemblages providing complementary nutritional resources and thermal responses.
These effects may become especially pronounced during heatwaves, defined as prolonged periods of higher temperatures relative to seasonal conditions, which are increasing in frequency and expose organisms to acute thermal stress (Smale et al. 2019). Heatwaves may have disproportionate consequences for predators, whose energy requirements increase more strongly with warming than those of their prey (Meehan et al. 2022). However, whether prey energetic diversity can buffer predators against the energetic challenges imposed by warming and heatwaves remains poorly understood.
Keywords
Warming, heatwaves, biodiversity, traits, energy, fitness, predator-prey, community, resilience.
Objectives
This project will investigate whether prey energetic diversity buffers predators against heatwaves in plankton communities. By combining previously acquired trait data with a predator-prey community experiment, we will test how prey energetic diversity – the diversity of energy budgets they provide to predators – interacts with predator size and with heatwave intensity to shape predator resilience and community stability.
Organisms
A planktonic predator–prey system composed of five algal prey species, Acutodesmus obliquus, Chlamydomonas reinhardtii, Chlorella vulgaris, Cryptomonas ovata and Monoraphidium minutum, and two grazers, Daphnia magna and Brachionus calyciflorus, representing contrasting body sizes, thermal responses and nutritional requirements.
Preliminary data
Existing data characterize the thermal responses of algal stoichiometry and grazer energy budgets and fitness across a 10–30°C gradient. These data reveal contrasting prey resources supporting grazer performance under warming.
Experimental design
A 30-day community experiment will test whether prey energetic diversity buffers grazers against heatwaves. Communities will combine three levels of prey energetic diversity with three heatwave intensities (24, 27, and 30°C) in a fully factorial design.
Data collection
Algal and grazer population dynamics, community composition, density, and body size will be monitored throughout repeated heatwave and recovery phases using microscopy, flow cytometry, and machine-learning classification.
Data analysis
We will quantify how prey energetic diversity and heatwave intensity affect community dynamics, grazer energy availability, resilience, and recovery from successive heatwaves.
Competences
We are seeking a motivated student with a strong interest in experimental ecology and environmental change. The student should ideally have a university or engineering background in ecology, environmental sciences, or climate change biology. Experience in laboratory experiments, ideally in microbiology, and skills in biostatistics would be an asset. Good scientific writing skills, autonomy, curiosity, and teamwork would also be appreciated.
Information
Starting date: January or February 2027
Duration: 6 months
Location: INRAE, RECOVER laboratory, 3275 route Cézanne, 13182 Aix-en-Provence, France
Language: French or English
Application
Deadline for application: November 9, 2026
Please send your CV and a motivation letter (1 page maximum, in French or English) to: tom.reveillon@inrae.fr and arnaud.sentis@inrae.fr
Informal enquiries are welcome. Please contact us by email in French or English. Applications will be reviewed on a rolling basis, with shortlisted candidates invited for an interview.
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