Incident-related special investigation programme for the environmental disaster in the Oder River of August 2022 (ODER~SO)

Researchers have compiled and analyzed the key environmental factors that led to the mass development of the brackish water alga Prymnesium parvum in the Oder in the summer of 2022. The data synthesis shows how multiple stressors combined to allow an alga that normally thrives in stagnant salt water to proliferate en masse in a completely atypical habitat. In addition, a study on the quantitative impact on fish stocks in the Oder was published: compared to before the disaster, fish and mussel stocks have been decimated by more than half.

Researchers from IGB sequenced the complete genome of the microalgae of the Oder disaster.They also identified the gene sequences that are responsible for toxin formation. This is an important step on the way to an early warning system. The study was published in the journal Current Biology.

In July and August 2022, a man-made environmental disaster occurred in the in the Oder River: a mass die-off of fish, mussels and snails that started in the Polish section of the Oder and then continued downstream until it reached the border Oder. The immediate cause of their death was a toxin-producing (planktonic) brackish water alga, scientifically known as Prymnesium parvum, which was able to grow en masse due to high salinity, high solar radiation, and low water flow. An IGB Fact Sheet summarises the current state of scientific knowledge.