Exploring animal life in the radioactive shadows of Chornobyl and Fukushima

A team of researchers in France is based on fundamental experimental research undertaken in the Ukrainian exclusion zone of Chornobyl with a new project in the Japanese prefecture of Fukushima to deepen our understanding of what it means for animals to live and to reproduce in radioactive environments.

Ms. Léa Dasque, a last year doctorate. The student of the Leco Laboratory (Laboratory of Ecology and Ecotoxicology of Radionuclides) under the French Nuclear Safety and Railation protection Authority (ASNR), supervised by the project project, Dr Olivier Armant, also from Leco and Asnr, aims to disentangle the Biological Interactions Network that shape radiological stress.

“We aim to answer a simple question: what is the current evolutionary and ecological status of wildlife populations residing in radio-contaminated areas, and how will they change over time?” said Ms. Dasque.

More recently, Ms. Dasque and her colleagues have studied the reproductive features of Japanese trees (Dryophytes Leopardus) living in the prefecture of Fukushima in Japan, site of the Fukushima Daiichi 2011 nuclear power plant.

The success of reproduction is the main driving force in life, but it is one of the biological processes most vulnerable to the harmful effects of ionizing radiation, making it an extremely important piece of the puzzle. “The ionizing radiation can disrupt the endocrine function, the gametogenesis and the coupling behaviors, which can all harm the fertility and the viability of the offspring,” explains Ms. Dasque.

“For example, our research in Chornobyl has documented a reduced body condition index and the size of small populations in very contaminated areas,” said Dr. Armant. “In Fukushima, we aim to discover if similar effects can also be observed after another major accident, and if the effects and reproduction are at the root of such effects observed in the population.”

To carry out their investigations, Ms. Dasque and Dr. Armant use a wide range of techniques and technologies that take place both in the field, namely Chornobyl and Fukushima, and under laboratory studies controlled in France.

“At the molecular level, we use genomics, transcriptomic and proteomics to identify cellular responses to exposure to ionizing radiation and the study of the effects at the level of the population,” explains Dr. Armant. At the body level, the team examines the body state, energy reserves and sexual characteristics.

In their most recent work on the qualities of reproduction of Fukushima’s trees, they also evaluated the sperm of male frog, energy metabolism and the characteristics of the calls. “These are extremely expensive to produce and closely linked to female attraction,” said Ms. Dasque.

A key discovery of the team’s work in Chornobyl is that the populations of amphibians in the most contaminated areas of the exclusion zone are fighting with poor genetic diversity compared to other populations, even decades after the accident. With the drop in bodily conditions, this questions the long -term viability of these populations.

Although the analysis of the Fukushima Frog project is still in progress, the preliminary results suggest that the frogs living in radiocontaminated areas are subject to a disturbance of the genetic routes associated with the motility of sperm – potentially modifying their reproductive success. “Other data on the motility of the sperm is currently being treatment to determine whether this parameter, as well as the male call behavior, can be affected by radiocontamination,” explains Ms. Dasque.

In the laboratory, the team also works on a project using zebra fish (Danio Rério), which revealed that chronic exposure to radiation alters neuromuscular development with consequences for motility and reduces sociability.

It is not only the vertebrates that are interested, because they also currently work in collaboration with the CNRS (French National Center for Scientific Research) to develop a methodology to measure the cognitive performance of wild pollinators living in Fukushima. “Cognition in pollinators, encompassing learning, memory and spatial navigation, is essential for the search for food and the functioning of effective colonies,” explains Dr. Armant. “Our initial data indicate a drop in cognitive performance correlated with exposure to radiation that could influence the behavior and survival of pollinators.”

“Combined exhibitions – such as radiation plus thermal stress – have the potential to produce non -predictable synergistic effects from unique stress models,” said Dr. Armant. “This calls for an evolution in the way we assess environmental risk: the one that embraces ecological realism, evolving dynamics and long -term surveillance.”

This project shows how the impacts on the success of reproduction are essential to long -term survival of radiocontaminated populations. “Without considering factors such as genetic diversity, migration patterns and life history features, we risk underestimating the real impact of chronic contamination on biodiversity and resilience of ecosystems”, explains Ms. Dasque.

This research is presented at the annual conference of the Society for Experimental Biology in Antwerp, Belgium, on July 11, 2025.