In the current context of global warming, a better understanding of the thermal sensitivity of ectothermic organisms seems essential, particularly in aquatic environments where species are highly sensitive and vulnerable to extreme climatic events such as heat waves. Consequently, the organism’s resistance to the effects of temperature is a determining trait for survival. For each species, tolerated temperature ranges and a maximum critical temperature value (CTmax) can be defined, at which the individual’s performance is severely reduced. Studies suggest that the thermal tolerance of organisms can be improved after a period of acclimation to high temperatures.
The aim of this internship will be to determine the thermal limits of a fish (medaka) and to study its potential for acclimation and/or adaptation to high temperatures. To this end, at INRAE laboratory in Aix-en-Provence, medakas have been exposed for several generations to cold (20°C) and warm (30°C) temperatures, then recently returned to ambiant temperature in mesocosms. These medakas will then be subjected to a simulated heat wave, followed by a CTmax measurement protocol, in order to study whether medakas exposed to hot temperatures for several generations are more resistant to thermal stress (heat wave and CTmax) than those exposed to cold temperatures.
The intern’s main task will be to take part in monitoring communities in mesocosms and to carry out measurements of thermal tolerance limits (CTmax) in the laboratory, under the supervision of a PhD student (Juliette Vallin), the technician in charge of medaka rearing (Remy Lassus) and a researcher (Arnaud Sentis). The latter task will involve setting up and implementing a scientific protocol for measuring CTmax (by gradually raising the temperature and assessing the threshold temperature at which the fish will lose equilibrium). The trainee will also be able to take part in the daily procedures of medaka rearing in the laboratory. The intern will then be required to transcribe the scientific approach and results in an internship report that could serve as the basis for a scientific publication. Through this internship, the student will acquire knowledge about: extreme climatic events & the thermal tolerances of ectotherms, methods for measuring thermal tolerance in fish, fish rearing in the laboratory, mesocosm experiments and the scientific approach. In addition, she/he will gain skills in data analysis using R software, as well as in scientific communication (writing up and presenting work).
The trainee will work in the FRESHCO team (Fonctionnement et REStauration des Hydrosystèmes COntinentaux) of the UMR RECOVER (Risques, ECOsystèmes, Vulnérabilité, Environnement, Résilience) of the INRAE laboratory in Aix-en-Provence. The FRESHCO team focuses on the functioning of continental hydrosystems, identifying the species present, the dynamics of species and populations, and assessing the consequences of anthropogenic pressures, in particular rising temperatures, on these ecosystems. Regular meetings will be organized to assess progress and find solutions to any problems encountered. The intern will also have the opportunity to exchange ideas with other members of the FRESCHO team.
Candidate skills:
We are looking for a highly motivated student with good organizational skills and a strong interest in aquatic ecology, climate change and the thermal limits of organisms. Master’s students in biology, ecology or a related field are welcome. Previous experience using spreadsheets (e.g. Excel) and statistical analysis (R software) will be appreciated.
To apply (before April 15), please send your CV and covering letter (1 page maximum) to Juliette Vallin (juliette.vallin@inrae.fr), Rémy Lassus (remy.lassus@inrae.fr), and Arnaud Sentis (arnaud.sentis@inrae.fr).
Practical information:
Start date (flexible): end of April or beginning of May 2024
Duration: 2 or 3 months
Location: INRAE, 3275 route Cézanne, 13182 Aix-en-Provence, France.
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