Biological granules appearing on Tuscan coasts

Mysterious white granules appearing on the coasts of Tuscany, including Elba Island and the gulfs of Baratti and Follonica, have undergone scientific investigation to determine their composition.

Initial analyses by ARPAT confirmed the material was of biological origin rather than plastic residue. Laboratory tests identified the substance primarily as sodium alginate, with microscopic examinations revealing structures linked to the tissues of higher plants. At that stage, researchers noted that no similar large-scale phenomenon had been previously documented in the Mediterranean.

Subsequent investigations by Arpat and botanists from the University of Siena identified the granules as decomposed water lentils, specifically the species ‘Lemna gibba’. These aquatic plants, typically green and found in freshwater environments like the Arno River, lost their chlorophyll during decomposition, resulting in their white appearance. Experts believe the plants traveled from the mouth of the Arno via marine currents, a phenomenon likely triggered by exceptional summer weather conditions and higher-than-normal water temperatures.

Further details indicate that these small, freshwater aquatic plants appeared in massive quantities in various rivers and lakes across Italy and Europe, including the Po and Reno rivers. They were specifically observed in the Arno River near Florence and Pisa during late summer 2026. The movement of the plants toward the south was driven by a combination of marine currents and winds.