Algae bloom in California, ©David McLain, Auroraphotos/CORBIS
It was an ecological time bomb.
In mid-2022, a toxic algal bloom began to quickly spread through the Oder River, which in part straddles the border between Germany and Poland. The algae, Prymnesium parvum, normally lives in the brackish waters near coastlines. But fed by salty run-off from industrial sites, and made more concentrated by low water levels, it enveloped huge stretches of one of Europe’s longest waterways.
The result was catastrophic.
During a six-week stretch from July to September, the algae is suspected to have killed 360 tonnes of fish. Such a massive die-off in the heart of Europe sparked handwringing and caused officials to ban bathing and fishing for many of the 16 million people who live in the Oder basin.
A recent European Union report found the crisis could have been averted with better monitoring of the Oder’s water. The event, say experts, is a prime example of why countries need to more closely track the health of their rivers, lakes and aquifers, which are facing mounting pressure from not only pollution but also climate change and biodiversity loss.
UNEP DHI Partnership – Centre on Water and Environment
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