school energy&environment

A fire-red lake

Lake Tovel, in the Trentino region, is known all over the world for the exceptional phenomenon of the “reddening of its waters”. During the hottest hours of some summer days, large portions of the lake surface took a deep red colour, offering an incredible sight. The spectacular colour was due to the strong concentration of a unicellular alga of the group Dinoflagellata, the Glenodinium sanguineum (also known as Woloszynskya coronata). This alga, which is just 1/50 mm long, under specific stress conditions, stores special pigments, called carotenoids, which make it look completely red. 1964 was the last year in which the reddening phenomenon appeared as clearly as usual; since then, the alga, although still living in the lake, has not reached the concentration it takes to ”inflame” the waters. Since 2001, the Provincia Autonoma di Trento has funded a research project for investigating the factors that are responsible for the missed reddening of the waters of Lake Tovel. The goal of the project is not to restore the conditions that in the past led to the flowering of the alga. The only purpose is to acquire all that information and details on the peculiarities of Lake Tovel that the local administrators need to make the best choices on the future of the lake. Lake Tovel is located in a lovely region, which attracts tourists and hikers, like many Alpine lakes, and is a precious water supply for the agriculture of the valley of the Trentino region, a reservoir of drinking water and, what’s more, an added value given by the phenomenon of the reddening of its waters.