Natural cause: foaming on the Saale river

Foaming is currently occurring on the Saale. This has led to a number of inquiries from the public to the city of Jena, including via the deficiency report. However, the cause is not pollution, but a natural phenomenon that occurs particularly in spring. There is therefore no cause for concern.

The strong sunlight of the past few days is currently reaching the water surface unhindered, as the deciduous trees do not yet have any shady leaves. At the same time, pollen and leaves from the previous fall provide a lot of nutrients. This combination leads to the so-called spring algae bloom. The algae release proteins that are "beaten up" on structures, such as weirs, and form the observed foam.

Foams produced by detergents or similar substances often differ from natural foams in their perfumed smell and rainbow-colored foam bubbles. Natural foams, on the other hand, are white to yellowish and also more unstable than artificial foams.