The study of Chornobyl Red Forest birch trees became possible through a collaboration between Ukrainian, Finnish and European researchers

The collaboration focuses on the ongoing effects of a nuclear accident on the environment. The study sheds light on the symbiosis of trees, and the interactions with microbes under stressful conditions.
The picture shows a microbe grown from a sample of silver birch from the Red Forest, each containing only one microbial species. Photo by Janne Koskimäki / University of Oulu

"In Ukraine, doing science has been very challenging during the war. Many scientists have needed to work under the threat of violence, and many have been forced to move to safer locations. International support has helped Ukrainian scientists to continue their work despite the difficult circumstances," says Ukrainian researcher Olga Podolich, who works at the University of Oulu, Finland.

The Chornobyl nuclear power plant reactor exploded in 1986 in what is now Ukraine (then the Soviet Union), causing one of the most serious nuclear accidents on Earth. Due to radioactive contamination and radiation, an isolated protection zone was established around the former power plant site. The most severely affected area was the forest near the power plant, where pine trees died and turned red from the intense radiation. The area is known as the Red Forest, where high levels of radiation can still be measured.

However, due to the lack of human activity, the biota in the Red Forest is very rich, and research is done there on the effects of elevated background radiation on organisms. The Fukushima accident in Japan (2011) showed that humanity needs to be prepared for nuclear accidents and to understand their consequences.

After Russia invaded Ukraine, early in the war, Russian soldiers occupied the Red Forest, digging up the soil and redistributing radioactive dust over the terrain. As a result, many long-term studies on the adaptation of organisms to radiation were disrupted. University of Oulu researchers Janne Koskimäki and Anna Maria Pirttilä, in collaboration with Ukrainian researchers Yevhen Tukalenko (National Research Center for Radiation Medicine, Kyiv) and Phillip C. Watts and Anton Lavrinienko of the University of Jyväskylä, Finland managed to collect samples of birch trees in the Red Forest before the war.

The picture shows a microbe grown from a sample of silver birch from the Red Forest, each containing only one microbial species. Photo by Janne Koskimäki / University of Oulu

Now the first results are starting to become available. Researchers at the University of Oulu hypothesised that the symbiosis with microbes could more easily become parasitic and harmful to birch trees due to radiation. However, preliminary results suggest that the birch is looking for new friends, and under the influence of stressful radiation, the birch is more loosely selecting for suitable symbionts.

Further studies are needed to find out why the birch has chosen new types of companions. "Are they perhaps better in helping the birch to grow under radiation?" Koskimäki wonders.

To answer these questions, a thorough study of the genetic heritage of the microbes is being carried out in collaboration with the European Reference Genome Atlas (ERGA), a European research network and genome map. The ERGA community aims to study and safeguard European species diversity, and the first results of the network's activities were published on 17 September 2024.

Last updated: 15.10.2024