Context – There is ample societal and scientific debate about the risks and the radioactive contamination on humans and natural ecosystems. In Chernobyl (Ukraine) and Fukushima (Japan) several years after the nuclear disasters there is still no scientific consensus about the long-term effects on wildlife of the chronic exposure to the remaining low-dose radiation levels in the areas affected by the radioactive fallouts.
Therefore, in order to better understand and quantify the ecological consequences of these nuclear accidents, we have undertaken field studies on two sentinel amphibian species, tree frogs Hyla orientalis in Chernobyl and Dryophytes japonicus in Fukushima). In particular, we used molecular ecology approaches, combining population genetic analyses to quantify the effects of radiocontamination on population evolution, and functional genomics to study the effects on individual health. Currently, a PhD student (2019-2023) is specifically studying the evolutionary responses of wildlife to Chernobyl and Fukushima. As of now, the study of genetic markers allowed us to show the existence of an abnormally high mitochondrial genetic diversity for the populations of tree frogs in the Chernobyl exclusion zone1. Using simulations of population evolution, the data showed a significant increase of the mitochondrial mutation rate associated with small population size probably explained by a negative impact of ionizing radiations on these tree frogs leading to a degraded physiological status.
1Car C., Gilles A., Armant O., […], Bonzom J-M. (2021). Unusual evolution of tree frog populations in the Chernobyl exclusion zone. Evolutionary Applications.

Objective – The overall objective of this PhD project is now to better understand and measure the effects of radio-contamination on the health of tree frogs. This research project will combine field work (Fukushima above all, and Chernobyl according to the geopolitical context during this PhD) and laboratory work. Several biological integration levels will be studied: physiological (e.g. hormone levels (stress and reproductive), oxidative stress, primary and secondary sexual characteristics), and behavioral (e.g. anti-predator behavior test), more integrative. All these parameters will be analyzed according to the radioactive dose absorbed by each individual.
Altogether, these results will enable to improve our understanding of the effects of radiocontamination on wildlife and to draw conclusions on the physiological status of the tree frogs present in two areas affected by a nuclear accident with a different chronicle.
The specifics of the project will be determined jointly by the successful candidate, supervisors and collaborators (see below).

Collaborative research – The student will benefit from the collaboration and the expertise of several researchers to complete his/her PhD. In physiology and behaviour: N. Mondy, T. Lengagne (Uni. Lyon 1), J-M Bonzom (IRSN); in genomic and transcriptomic: O. Armant (IRSN); in proteomic: S. Frelon (IRSN); in radioecology: J-M Bonzom (IRSN); in field work: I. Miura (Institute for Amphibian Biology, Hiroshima University, Japan), K. Nanba and H. Ishiniwa (Institute of Environmental Radioactivity (IER), Fukushima University, Japan), S. Gaschak (International Radioecology Laboratory, Ukraine), and J-M Bonzom.

Candidate profile – The candidates must hold a Master degree in a relevant field (e.g. ecology, ecophysiology, ecotoxicology, molecular ecology, …). The ideal candidate is highly motivated, hardworking, creative, and has experience from fieldwork and laboratory work. Moreover, he/she will not be afraid to handle and dissect frogs. The student has to be able to work independently as well as a part of a team. The working language is French and English.

Additional information – The PhD will start in October 2022 and is funded for three years in the Research laboratory on the effects of radionuclides on ecosystems (LECO). At LECO the student will be supervised by Dr. S. Frelon, Dr. O. Armant, and Dr. J-M Bonzom. LECO is a laboratory of the French Institute for Radioprotection and Nuclear Safety (IRSN) in Cadarache (located in the south of France: 30 minutes from Aix-en-Provence and Manosque; 1 hour from Marseille).
This project is also supervised by Dr. Nathalie Mondy (UMR 5023 – LEHNA, Université Lyon 1), and missions will be planned in Lyon.
Possibility of furnished apartment close to LECO/IRSN-Cadarache laboratory (at approximately 500m: ).

Contact persons – To apply or for any questions, please contact by email before April 1st, 2022: ; ; ;
Send a short motivation letter with a description of pertinent experience, a CV, the names and e-mail addresses of two or three academic/research references, and copies of certificates of academic qualifications (in French or in English).

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