Ecosystem is very vulnerable: Toxic Oder water threatens the only floodplain national park

The fish kill in the Oder continues.

Ecosystem is very vulnerable: Toxic Oder water threatens the only floodplain national park

The fish kill in the Oder continues. Thanks to protective mechanisms, the apparently toxic river water has not yet entered the Lower Oder Valley National Park. That could change in autumn, however, when the polders reopen. Then sea eagles, cormorants and kingfishers are also in danger.

Germany's only floodplain national park on the Oder is actually a peaceful place, a paradise for waterfowl as a breeding, resting and wintering place. It is a large-scale German-Polish project around 30 kilometers south of the Szczecin Lagoon, 150 kilometers south of the Baltic Sea island of Usedom.

Every year in spring and autumn, this area attracts nature lovers who watch the passage of thousands of ducks, geese or cranes. On this August morning, an osprey circles over the water - a sublime sight. But as the morning fog lifts, the extent of the current environmental catastrophe becomes visible and an indescribable stench fills your nostrils. Countless dead fish swim on the river - large bream, roach, asp - mostly white fish rotting in the water of the Oder, not far from the floodplains of the national park.

Ingo Kapuhs has been a ranger in the protected area for 30 years. In his guided tours, he talks about a sensitive ecosystem that is subject to the ever-increasing impact of humans and climate change. Now the conservationist is one of the volunteers who - equipped with rubber boots, landing net and protective gear - fetch tons of dead fish from the river in the sweltering heat. "I've never seen anything like it here," says Kapuhs.

Was he angry at the Polish authorities, who informed them late about the fish kill? It is difficult for the conservationist to remain factual. "They just covered up the facts and let it matter what happened. They just wanted to sweep it under the carpet," he believes. It is not yet foreseeable what long-term consequences the environmental catastrophe will have for fish, animals and plants in the Oder region and the Baltic Sea. Also because it is still not clear which toxic substances have led to the mass death of fish.

The federal government expects meaningful test results. The State Environment Agency has now informed about the first laboratory results. According to the Brandenburg Ministry of the Environment, these did not show any particularly high values ​​for metals such as mercury. Furthermore, high salt loads and a high oxygen content are found. The environmental association BUND estimates that up to 100 tons of fish have died. 500 kilometers of river are affected.

Poland assumes that a huge amount of chemical waste was dumped into the Oder. The national park in the Uckermark saved itself in the disaster. The polders are closed as usual in summer. The Oder water, with the still unknown toxic substances, did not get into the protected area. From November it is to be let in again for the floodplains.

Jana Chmieleski from the national park administration is still worried because the danger for white-tailed eagles, cormorants, otters and kingfishers remains. It is critical that the fish already have heavy metals in them and the birds include them in the food chain. The environmental catastrophe also affected research projects such as those of Jörn Gessner and his team from the Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB). The researchers are trying, among other things, to resettle Atlantic sturgeons in Germany, also in the Lower Oder Valley. The rearing of young sturgeon has suffered far-reaching losses, he now reports. Next week his team wants to take soil samples to see whether microorganisms are also affected.

At the point where the West-Oder and its main branch separate, a barrier has now been drawn to prevent the dead animals from drifting on. The collection is difficult, it is only possible from the bank edge. A boat would help, but the actors don't know whether that will still happen. Doreen Bandelmann and her son Luca volunteered to collect the fish carcasses via a Whatsapp group that had been set up. "Helping at least gives the feeling of doing something," they say.

For scientist Chmieleski, despite all the evil, the environmental catastrophe has produced something else: an opportunity to educate the population. The environmental catastrophe clearly shows the vulnerability of ecosystems and how important it is to protect large areas, she says. "This moment will eventually be over, but what we are currently seeing is just a symptom of everything we are seeing across Europe at the same time," the 50-year-old is convinced.

Meanwhile, a motorboat is driving on the Polish side of the Oder - away from the fish carcasses and volunteers and without any offer of help. The volunteers continue to fish from the edge in the murky water. Communication with the national park partner on the Polish side is not easy, says Chmieleski.