Algae blooms, whose toxins cause massive fish die-offs and the death of other organisms, are becoming more frequent in the waters of Polish rivers (including the Oder River). Their main cause is high salinity, which further increases during periods of low water levels.
The fight against blooms, is not only to reduce emissions of pollutants, but also to remediate, that is, to clean the waters of excess nutrients already present. For this purpose, natural solutions (nature-based solutions) are used, an example of which are plant filter islands – hydrophytes kept on the surface of the water by special rafts take up the macro- and micro-elements they need for growth, thereby reducing salinity levels.
In addition, plant filter islands contribute to the biodiversity of watercourses and improve the continuity of ecological corridors. During an inspection of the installation carried out by the Water Institute, the presence of crayfish was observed in the structure of the islands, which require particularly favorable conditions to grow.
To fully exploit the potential of the solution, it must be significantly scaled up and implemented in particular in regulated areas where natural aquatic vegetation is lacking.
