What happened to the frogs near Chernobyl?

A new study in the Journal of Evolutionary Applications has found that frogs in areas close to the Chernobyl nuclear accident have much darker skin comapred to their cousins further from the exclusion zone.

Titled ‘Ionizing radiation and melanism in Chornobyl tree frogs’, Spanish researchers Pablo Burraco and Germán Orizaola wanted to discover the human impact on ecosystems. They decided that the Chernobyl plant would be a good place to start, saying it was a “key scenario” considering it was the largest release of radioactive material into the environment in human history.

The next step was choosing a suitable animal to analyse. They settled upon frogs as amphibians occupy both land and water environments, exposing them to the most radiation. The Eastern tree frog (Hyla orientalis) was selected and research began in 2017 through to 2019. The researchers collected samples at different distances from the exclusion zone.

Results showed the further from the exclusion zone the frogs lived, the brighter their skin was. Melanin, the part of the skin which determines it colour, is known to provide protection from radiation, hence people living closer to the equator having darker skin compared to people from the arctic circle. The study suggests the skin tone of the frogs is based upon historical, but not current, exposure to radiation levels. The frogs with high melanin in their skin prior to the nuclear disaster continue to survive in areas closer to the exlucsion zone compared to those with lighter skin.

“Melanin is known to protect against radiation because it can mechanically avoid the production of free radicals caused by the direct impact of the radioactive particles on cells,” Burraco told Live Science in an email.