Why doesn’t Lake Tovel turn red anymore?

Lago di Tovel

Lake Tovel is an alpine lake located in Val di Tovel, within the Adamello-Brenta Natural Park, in the municipality of Ville d’Anaunia in Trentino.

It is located at an altitude of 1177 metres above sea level and is famous for the characteristic reddening that occurred during the summer months, caused by the flowering of the alga Tovellia Sanguinea.

The last strong episode of reddening was in the summer of 1964, but there were some signs of the phenomenon in subsequent years, such as in 1965 and 1967, then again in 1977 and 1978. Finally, there were slight signs of reddening in 1982 and 1983.

Recent studies have shown that the disappearance of the reddening phenomenon is due to the lack of organic load, such as nitrogen and phosphorous, which was caused by the cattle herds grazing near the lake.