Despite surviving for a long time in a radioactive environment after the Chernobyl disaster, the lifespan of eastern tree frogs seems to be unaffected.
In 1986, the Chernobyl nuclear disaster released the largest amount of radioactive material into the environment in human history. This catastrophe had devastating effects on all forms of life, but researchers still do not fully understand how the accident has impacted wildlife in Ukraine today. A new study published in the journal Biology Letters indicates that for the eastern tree frog (Hyla orientalis), long-term exposure to a radioactive environment does not seem to alter their lifespan, according to IFL Science.
Eastern tree frog (Hyla orientalis). (Photo: Germán Orizaola)
With the absence of humans, the Chernobyl exclusion zone has become one of the largest natural reserves in Europe. “I believe the current levels of radiation in the Chernobyl exclusion zone are not enough to cause significant harm to wildlife, at least in most areas,” stated Pablo Burraco, a researcher at the Estación Biológica de Doñana.
During two weeks of work in several heavily contaminated areas (spending a few hours each day), the research team accumulated radiation exposure equivalent to that of a dental visit. This is because the most dangerous radioactive isotopes released during the Chernobyl accident have very short half-lives, leading to a rapid decline in radiation levels within a few months or years.
Burraco is a member of the research team led by Germán Orizaola. They conducted field studies in Chernobyl from 2016 to 2018, focusing particularly on eastern tree frog populations. They collected samples from frog populations in Chernobyl across various levels of radioactive contamination, gathering over 200 male frogs. In a laboratory environment, they assessed the age of the frogs, the amount of radiation they absorbed, the levels of the stress hormone corticosterone, and determined their aging status using telomere length. Telomeres are structures that help protect the ends of chromosomes from external damage.
The results showed that there were no differences in lifespan, aging rates, or stress indicators in tree frogs from Chernobyl compared to those living in non-radioactive areas, indicating that the radiation levels in the area are no longer sufficient to cause chronic harm. According to the research team, these findings reinforce the role of the Chernobyl exclusion zone as a wildlife sanctuary. The current low levels of radiation are a key factor, but the frogs have also adapted to survive high radiation levels. Previous studies have revealed how they evolved a pigmentation change, shifting from green to black to protect their bodies from radiation.
Researchers hope to continue their work to better assess the current impact of the Chernobyl disaster on wildlife, but they have had to pause due to the ongoing Russia-Ukraine conflict.
