Lake Garda Anabaena Disappears After Short Bloom, Experts Confirm

The current status of anabaena in Lake Garda

It disappeared just as quickly as it arrived: just two or three days of rising water temperatures and a change in current patterns were enough to make the notorious anabaena, the single-celled algae that made headlines about two weeks ago for colouring the ports and beaches of Rivoli with green, vanish rapidly from the surface of Garda.

Therefore, the experts (such as hydrobiologist Alvise Vittori, geologist Vincenzo Ceschini, and Dr. Chiara De Francesco from the Provincial Observatory of Porto San Nicolò) were right when they said that the slime, first observed in the upper lake — but already seen about ten years ago in the Brescia area — would disappear once Lake Garda stabilized after a season characterized by strange climatic and physical phenomena (water overturning and sesse).

Impact on bathing and tourists

As remembered, the anabaena caused quite a stir among the tourism sector: its total innocuousness was demonstrated by the water bathing suitability data (which this year was really excellent), and it was also confirmed that the algae was not «fed» by a proliferation of nutrients (laboratory tests showed that nitrate and phosphate levels in the lake remained unchanged). Yet, despite all this… it looked disgusting.

Both for the aesthetic effects (no one would have ever dreamed of swimming in it) and for the odors it released along the lakeshore.

Current situation and future monitoring

Now, as we said, the anabaena is gone. Dead on the surface, it has gradually sunk, as phytoplankton usually does when it is not renewed. Tomorrow, Dr. De Francesco will carry out further tests to precisely assess how much algae remains dissolved at various depths (less algae, the more likely it is that the lake will regain its beautiful blue colour), but it is already visibly clear that the situation is under control.